JP2017028917A - Power conditioner monitoring system and solar power generation plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve "reduction of monitoring burden", "overall monitoring of a plant" and "suppression of false report" simultaneously by determining presence or absence of an abnormality in a solar power generation plant, on the basis of the fact that the plant illuminance measured by an illuminance sensor goes above an illuminance threshold, only when the current value or the like from a power conditioner goes below an output threshold.SOLUTION: A monitoring system 1 determines presence or absence of an abnormality in a solar power generation plant P having a power conditioner C for converting the current from a solar cell D from DC to AC. The monitoring system 1 includes an illuminance sensor 2 for measuring a plant illuminance L in the solar power generation plant P, and a determination unit 3 for counting the number of times of error E where the plant illuminance L goes above an illuminance threshold T2 while a power conditioner output value M, including the value of at least one of the current, voltage and power from the power conditioner C, goes below an output threshold T1, and determining that there is an abnormality in the solar power generation plant P when the number of times of error E goes above an error threshold T3.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a monitoring system that determines the presence or absence of an abnormality in a solar power generation plant having a power conditioner that converts current from a solar cell from direct current to alternating current, and a solar power generation plant that includes this monitoring system.

Conventionally, inspection of a solar cell system including a solar cell panel array composed of a plurality of solar cell panels and a power conditioner that is connected to the solar cell panel array and obtains maximum electric power from the solar cell panel array by maximum power tracking control. A method is known (Patent Document 1).
This inspection method uses a dimming means for changing the degree of dimming of sunlight at a predetermined cycle, and a dimming step for changing the illuminance of sunlight irradiated to a partial area of the solar cell panel array at a predetermined cycle. In the state where the illuminance of sunlight is changed at a predetermined cycle by the dimming process, the current output from the solar cell panel array to the power conditioner is measured using a current detector, and the measured current is changed at a predetermined cycle. Output from the solar panel array to the power conditioner using a voltage detector with the current component detection process detecting the changing current component as a generated current and the illuminance of sunlight changing at a predetermined cycle by the dimming process A voltage detection step of detecting the measured voltage simultaneously with the current measurement, and detecting the measured voltage as a generation voltage; a generation current detected in the current component detection step; A power generation amount calculation step for calculating a power generation amount in a partial region of the solar cell panel array based on a variation in illuminance that changes in a predetermined cycle using the power generation voltage detected in the detection step, and a power generation amount calculation step And a determination step of determining pass / fail of a partial region of the solar cell panel array using the generated power generation amount.

JP2013-131679A

However, the inspection method described in Patent Document 1 cannot be used to inspect a solar cell system without using a dimming means, and the inspection takes time and effort, and naturally, only the amount of sunlight is reduced. The power generated is also reduced.
Further, since the inspection method of Patent Document 1 can be inspected only for a part of the solar panel array, it is determined that there is an abnormality even if there is an abnormality in the solar panel array other than using the dimming means. Not.

Furthermore, in Patent Document 1, if the illuminance is large to some extent in the solar cell panel, the power generation amount is substantially proportional to the illuminance (paragraph 0010), and the maximum output of the power conditioner is substantially proportional to the illuminance (paragraph 0036). It is stated.
However, when actually examined, as shown in FIG. 4 and FIG. 5 (a), in a normal solar cell system (solar power generation plant), the illuminance is increased (brighter). In some cases, the output current of the inverter is decreasing.
That is, in the inspection method of Patent Document 1, even if there is no abnormality in the photovoltaic power plant, if the output of the power conditioner is not proportional to the illuminance, it is determined that there is an abnormality, which causes a false alarm. If the illuminance referred to in Patent Document 1 is irradiance, Patent Document 1 does not have any suggestion to use illuminance in units of lux [lx].

  In view of such a point, the present invention is based on whether the plant illuminance output from the illuminance sensor is equal to or greater than the illuminance threshold only when the current value from the power conditioner is equal to or less than the output threshold. It is an object of the present invention to provide a monitoring system and a photovoltaic power generation plant that can simultaneously realize “reduction of monitoring burden”, “overall monitoring of a plant”, and “suppression of false alarms” by determining whether or not there is an abnormality.

  A monitoring system 1 according to the present invention is a monitoring system for determining the presence or absence of abnormality of a solar power plant having a power conditioner that converts a current from a solar cell from direct current to alternating current, and the plant in the solar power plant While the illuminance sensor that measures illuminance and the power conditioner output value including at least one of the current, voltage, and power from the power conditioner is less than or equal to the output threshold, the error that the plant illuminance is greater than or equal to the illuminance threshold A first feature is that it includes a determination unit that counts the number of times and determines that there is an abnormality in the solar power plant if the number of errors exceeds an error threshold number.

  The second feature of the monitoring system 1 according to the present invention is that, in addition to the first feature, the illuminance threshold value can be changed while the judgment unit judges whether there is an abnormality in the photovoltaic power plant. It is a point that is a threshold.

  A third feature of the monitoring system 1 according to the present invention is that, in addition to the first feature or the second feature, the determination unit determines that the plant illuminance is the illuminance while the power converter output value is equal to or less than the output threshold. Even if it becomes more than a threshold value, if the said plant illumination intensity becomes more than the high illumination intensity threshold value larger than the said illumination intensity threshold value, it exists in the point which is not counted as the said error frequency.

Due to these characteristics, while the power conditioner output value M including the current from the power conditioner C is equal to or less than the output threshold T1, the number of errors E that are greater than or equal to the illuminance threshold T2 of the plant illuminance L by the illuminance sensor 2 is If it becomes several T3 or more, it will not be necessary to use a dimming means like patent document 1 by judging with the judgment part 3 that there exists abnormality in the photovoltaic power plant P, and monitoring of the photovoltaic power plant P Can be reduced ("reducing the monitoring burden") and there is no reduction in the amount of power generated by dimming means.
In addition to this, since the presence or absence of abnormality is determined based on the current value from the power conditioner C, the entire photovoltaic power plant P including any solar cells D can be monitored ("" Overall monitoring of the plant ").
Then, as shown in FIG. 5 (c), the illuminance sensor 2 is connected to the illuminance sensor 2 only while the correlation between the power conditioner output value M of the power conditioner C and the plant illuminance L is high (the power conditioner output value M is equal to or less than the output threshold T1). Since the presence / absence of abnormality is determined based on this, misreporting of abnormality determination can be suppressed (“inhibition of misreporting”), and an illuminance sensor (illuminance meter) with a lower cost burden than a pyranometer can be utilized.

  Further, by setting the illuminance threshold T2 as a threshold that can be changed while the determination unit 3 determines whether or not there is an abnormality in the solar power plant P, the environment under which the solar power plant P is placed (illuminance sensor). The illuminance threshold value T2 can be optimized in accordance with the two mounting directions (the vertical direction such as the horizontal direction, the vertical direction, and the oblique direction, the direction of the sun, etc.)

Furthermore, if the plant illuminance L is equal to or greater than the illuminance threshold T2, but is also greater than or equal to the high illuminance threshold T2 ′ that is greater than the illuminance threshold T2, by not counting as the number of errors E, for example, more misinformation during snowfall Can be suppressed.
Specifically, when snow is accumulated due to snowfall, even in a normal (non-abnormal) photovoltaic power plant P, the plant illuminance L, even though the current value from the power conditioner C is less than or equal to the output threshold T1. May exceed the illuminance threshold T2.
This is because sunlight is reflected by the accumulated snow and becomes brighter (the plant illuminance L becomes higher). Here, a high illuminance threshold T2 ′ larger than the illuminance threshold T2 is provided, and the high illuminance threshold T2 ′ or higher is provided. If the number of errors E is not counted when the plant illuminance L is reached, it can be distinguished whether the illuminance increase due to snow accumulation or an abnormality of the photovoltaic power plant P, and false alarms are suppressed.
In addition to this, it is possible to improve the false alarm suppression even when the solar power plant P is placed in a place where the sunlight can be reflected on the water surface, such as the seaside, lakeside, riverside, etc., except during snowfall.
The photovoltaic power plant P according to the present invention includes the above-described monitoring system and a communication unit that communicates the determination result of the presence or absence of abnormality of the monitoring system with respect to the photovoltaic power plant to the outside of the monitoring system. This may be a feature.

  According to the monitoring system and the photovoltaic power plant according to the present invention, only when the current value from the power conditioner is equal to or lower than the output threshold value, whether the plant illuminance output from the illuminance sensor is equal to or higher than the illuminance threshold value. By judging whether there is an abnormality, it is possible to simultaneously realize “reducing the monitoring burden”, “overall monitoring of the plant”, and “suppressing false alarms”.

It is a schematic diagram showing a monitoring system and a photovoltaic power plant according to the present invention. It is a schematic diagram which shows the notification from a monitoring system, Comprising: (a) shows the structural example by SMS delivery, (b) shows the structural example by the mail delivery via a server. It is a drawing substitute photograph which shows the attachment condition of the illuminance sensor of a monitoring system, (a) shows the condition where the illuminance sensor was attached to the photovoltaic power generation plant on the roof of a certain building with the light receiving part oriented substantially in the horizontal direction, (b ) Shows a situation in which the illuminance sensor is attached to the photovoltaic power plant on the roof of the same building as (a) with the light receiving portion oriented in a substantially vertical direction, and (c) shows the light receiving portion substantially horizontal to another photovoltaic power plant. The situation where the illuminance sensor is attached in the direction is shown. It is a graph which shows the change of the power inverter output value and plant illuminance of a photovoltaic power plant in a certain sunny day. It is a graph about the power conditioner output value and plant illuminance of a photovoltaic power plant in other sunny days, (a) shows change of power conditioner output value and plant illuminance, (b) is the power conditioner in the whole area of power conditioner output value The correlation between the output value and the plant illuminance is shown, and (c) shows the correlation between the power control output value and the plant illuminance in a range where the power control output value is equal to or less than the output threshold. It is a graph about the power condition output value and plant illuminance of a photovoltaic power plant in a cloudy day or a rainy day, (a) shows change of power condition output value and plant illuminance, (b) is the whole area of power condition output value (C) shows the correlation between the power control output value and the plant illuminance in the range where the power control output value is equal to or less than the output threshold value. It is a graph which shows the case where the misreport of abnormality presence does not generate | occur | produce, when not determining the presence or absence of abnormality based on plant illumination intensity. It is a graph which shows the case where the false alarm | report of the presence or absence of abnormality has generate | occur | produced by the influence of a typhoon, when not judging the presence or absence of abnormality based on plant illumination intensity. It is a graph which shows the case where the false report of the presence or absence of abnormality has generate | occur | produced by the influence of rain, when the judgment of the presence or absence of abnormality based on plant illumination intensity is not carried out. It is a flowchart which shows a monitoring program. It is a graph which shows the case where it was checked whether the abnormality existence was judged normally by manipulating a power conditioner output value and plant illuminance, when judging the existence of abnormality based on plant illuminance. When the presence or absence of abnormality is determined based on plant illuminance, the power conditioner output value is equal to or less than the output threshold value, but the plant illuminance is also equal to or less than the illuminance threshold value. In the case of determining whether there is an abnormality based on the plant illuminance, the power conditioner output value is equal to or less than the output threshold value, and the plant illuminance is equal to or greater than the illuminance threshold value. is there. In the case of determining whether there is an abnormality based on the plant illuminance, the power conditioner output value is equal to or less than the output threshold, and the plant illuminance is equal to or greater than the illuminance threshold. is there. It is a graph which shows the example which calculated | required the correlation coefficient and the regression line based on the sample of August 31, 2014 in the range whose power control output value is below an output threshold value. In a certain solar power plant, when the illuminance sensor is mounted so that the light receiving portion (normal line of the light receiving surface) is substantially horizontal, August 29 to 31, 2014, September 1, 2, and 6, 2014 Graph showing power generation status (power converter output value, plant illuminance, temperature change), correlation (correlation between power converter output value and plant illuminance in a range where the power converter output value is below the output threshold), correlation The numbers, regression lines, and illuminance thresholds that are expected when the output threshold is 2.5 A are summarized. In a certain photovoltaic power plant, when the illuminance sensor is mounted so that the light receiving portion (normal line of the light receiving surface) is substantially vertical, the power generation status (power condition output value, plant illuminance, A graph showing a change in temperature), a graph showing a correlation (a correlation between a power converter output value and a plant illuminance in a range where the power converter output value is equal to or less than the output threshold value), a correlation coefficient, a regression line, and an output threshold value of 2 This is a summary of illuminance thresholds expected when .5A is set. In another solar power plant, when the illuminance sensor is mounted so that the light receiving part (normal line of the light receiving surface) is substantially horizontal, the power generation status (power converter output value, plant illuminance on September 14-18, 2014) , A graph showing a change in temperature), a graph showing a correlation (a correlation between a power converter output value and a plant illuminance in a range where the power converter output value is equal to or less than the output threshold), a correlation coefficient, a regression line, and an output threshold It summarizes the illuminance thresholds expected when 2.5 A. It is a graph which shows the change of the power inverter output value and plant illumination intensity of a solar power generation plant on a snowy day.

Embodiments of the present invention will be described below with reference to the drawings.
<Overall configuration of photovoltaic power plant P>
1 to 3 show a monitoring system 1 according to the present invention, a solar battery D, a power conditioner (power conditioner, PCS) C, and a photovoltaic power plant according to the present invention provided with these monitoring systems 1 ( Solar power plant) P is shown.
The photovoltaic power plant P may include a solar cell string R (string R) configured by connecting a plurality of solar cells D in series, or an AC current collection box (power transmission panel) B. The string R There may be more than one.

<Solar cell D, solar cell string R>
As shown in FIGS. 1 and 3, the individual solar cells D in the solar cell string R generate direct-current power between the positive electrode (+ electrode) and the negative electrode (−electrode) when irradiated with light, The average generated power is about 100 to 300 W (for example, 250 W).
The shape of the solar cell D is not particularly limited, but may be, for example, a panel shape.
Among these solar cells D, the negative electrode of another solar cell D is connected to the positive electrode of one solar cell D, the negative electrode of another solar cell D is connected to the positive electrode of another solar cell D, Hereinafter, by repeating this, a plurality of (for example, 5 to 20) solar cells D are connected in series to form one solar cell string R.

Thus, the voltage between the + pole (power output end) and the − pole (ground end) of the entire solar cell string R in which a plurality of solar cells D are connected in series is generated in each solar cell D. It is the sum of the DC voltages, and varies depending on the weather, time of day, deterioration of each solar cell D, failure, displacement of the installation position, etc., but is about 200 to 1000V.
The power output from the power output terminal of the solar cell string R is the sum of the power of each solar cell D, and is about 500 to 6000 W (for example, when 14 solar cells D having an output power of 250 W are connected) 3500 W = 3.5 kW).

<Power conditioner C, AC power transmission box B>
As shown in FIG. 1, the power conditioner C converts the current from the solar cell D from direct current to alternating current, and may be any configuration as long as it converts direct current from alternating current. .
The above-described solar cells D (or solar cell strings R) are electrically connected to the power conditioner C, and the power conditioner C is connected to a power distribution network (not shown) via the AC current collection box B and the cable K. ) May be conducted.

Furthermore, in one photovoltaic power plant P, a plurality of power conditioners C are provided, or output values of the plurality of power conditioners C (at least of current, voltage, and power from the power conditioner C). A configuration in which a power converter output value including one value) M is collected in one AC current collection box B and then conducted to a distribution network may be employed.
The monitoring system 1 to be described later may read the power conditioner output value M of the power conditioner C in the AC current collection box B.

In addition to this, the solar power plant P has a transformer (transformer, not shown) that changes the alternating current from the power conditioner C into a higher-voltage alternating current, and a plurality of (for example, 5 to 15) solar cells described above. A connection box (not shown) in which battery strings R are connected in parallel; a DC current collector (not shown) that collects a DC current from the solar battery D; a solarimeter (not shown) that measures solar radiation intensity; You may have the temperature sensor (illustration omitted) which measures temperature, and the auxiliary machine which supplies an electric current to the power conditioner C mentioned above, a solar radiation meter, a temperature sensor, etc.
<Overall configuration of monitoring system 1>

As shown in FIGS. 1 to 3, the monitoring system 1 according to the present invention is a device that determines whether there is an abnormality in the photovoltaic power plant P (particularly, the power conditioner C) having the power conditioner C.
The monitoring system 1 includes an illuminance sensor 2 that measures illuminance and a determination unit 3 that determines whether there is an abnormality in the solar power plant P. If this judgment part 3 judges whether there is abnormality in photovoltaic power plant P, there is no restriction in the installation place and composition.
In addition, the monitoring system 1 includes a measurement unit 11 that measures a power conditioner output value M from the power conditioner C, a signal conversion unit 12 that converts signals from the measurement unit 11 and the illuminance sensor 2, and a determination result of the determination unit 3. And a storage unit (not shown) for storing the power conditioner output value M from the power conditioner C and the plant illuminance L from the illuminance sensor 2.

<Illuminance sensor 2>
As shown in FIGS. 1 and 3, the illuminance sensor 2 is a sensor that measures the plant illuminance L in the photovoltaic power plant P.
The “plant illuminance L in the solar power plant P” means the illuminance in the environment where the solar power plant P is placed, and this illuminance is referred to as “plant illuminance L”.
Further, the “illuminance” in the present invention is “light flux incident per unit area of the surface receiving radiation” defined in JIS-Z-8113: 1998, and the unit is lux [lx], or Lumen per square meter [lm · m ^-2 ].

The illuminance sensor 2 may have any configuration as long as it can measure the plant illuminance L. For example, a photodiode that passes a current proportional to the illuminance of the irradiated light, or a current from the photodiode is connected to an OP amplifier. A configuration that converts the voltage into a voltage using a resistor may be used.
Hereinafter, the illuminance sensor 2 will mainly be described as a configuration that generates a voltage proportional to the illuminance of light irradiated on the illuminance sensor 2.

The illuminance sensor 2 includes a light receiving portion 2a on which light is incident (receives light), and light incident from the light receiving portion 2a is applied to the photodiode.
In the illuminance sensor 2, the measured plant illuminance L differs depending on the incident angle of light with respect to the light receiving unit 2a (the greater the incident angle, the smaller the actually measured plant illuminance L).
The incident angle of light with respect to the light receiving portion 2a is an angle θ between the normal line (optical axis) on the light receiving surface of the photodiode and the incident direction of incident light, and the illuminance when the incident angle is 0 °. The value of (plant illuminance L) is multiplied by cos θ (assuming that the intensity of illuminance when certain light is incident at an incident angle of 0 ° is Q, the illuminance when the incident angle is θ is The size is Q × cos θ).

As described above, since the light may enter the illuminance sensor 2 at a predetermined incident angle θ (incident obliquely), the illuminance sensor 2 may perform cosine correction (correction to correctly measure obliquely incident light. (Correction of oblique incident light characteristics (light receiving angle characteristics)) may be performed.
In addition, the illuminance sensor 2 may conform to a general type precision class illuminometer, a general type AA illuminometer, or a general class A illuminometer specified in JIS-C-1609-1: 2006, and correction of visibility. (Correction to match the characteristics of the illuminance sensor 2 with the visible range relative spectral response characteristics of the human eye) may be performed.

The illuminance sensor 2 may be provided anywhere as long as it can measure the plant illuminance L in the environment where the photovoltaic power plant P is placed. For example, the illuminance sensor 2 is a solar cell (solar cell) in the photovoltaic power plant P. Panel) D (for example, the back side of the panel) may be provided.
In this case, the illuminance sensor 2 may be attached to the solar cell D (for example, on the back side) (see FIG. 3) with the light receiving portion 2a oriented in a substantially horizontal direction or a substantially vertical (vertical) direction.

Here, the direction of the light receiving portion 2a in a substantially horizontal direction or a substantially vertical direction means that the normal line (optical axis) on the light receiving surface of the photodiode described above is directed in a substantially horizontal direction or a substantially vertical direction.
In addition, “a certain photovoltaic power generation plant P” described in the simple description of the drawings in FIGS. 3A and 3B is an A power plant provided on the roof of a building (in FIG. The “other photovoltaic power plant P” described in the brief description of FIG. 3C is the B power plant provided in the vacant land (in FIG. 18, “B power plant”). It is provided at the installation site.
Note that the illuminance sensor 2 has characteristics conforming to JIS-C-1609-2: 2008, such as the above-described visible range relative spectral response characteristics, oblique incident light characteristics, and temperature characteristics, and outputs based on these characteristics. In addition to voltage correction, A / D conversion may be performed collectively by the signal conversion unit 12 described later.

<Decision unit 3>
As shown in FIGS. 1 and 2, the determination unit 3 determines whether or not the photovoltaic power plant P (particularly, the power conditioner C) is abnormal. Specifically, the power condition output value M is an output threshold value T1. During the period below, the number of errors E in which the plant illuminance L is equal to or greater than the illuminance threshold T2 is counted, and if the number of errors E is equal to or greater than the error threshold number T3, it is determined that the photovoltaic power plant P is abnormal.
In other words, the determination unit 3 indicates that the photovoltaic power plant P is “normally operating” (that is, there is no abnormality in the photovoltaic power plant P) while the power converter output value M is larger than the output threshold value T1. You may judge.

As a result, the presence / absence of an abnormality is determined based on the illuminance sensor 2 only while the correlation between the power conditioner output value M of the power conditioner C and the plant illuminance L is high. Along with “suppression”), an illuminance sensor (illuminometer) that is less costly than a pyranometer can be used.
The determination unit 3 may have any configuration as long as it can determine whether the photovoltaic power plant P is abnormal. For example, the determination unit 3 is a CPU (central processing unit) that executes a monitoring program (monitoring algorithm) S described later. In addition, when the monitoring system 1 does not have the storage unit described above, the determination unit 3 stores a power control output value M from the measurement unit 11 described later and a plant illuminance L from the illuminance sensor 2. Storage devices (memory, storage media such as a hard disk, a DVD, and a CD) may be provided.
If the determination unit 3 determines whether there is an abnormality in the solar power plant P, the installation location is not limited as described above. The determination unit 3 may be provided.
In addition, the determination unit 3 has a configuration in which the cloud server N and the monitoring room A communicated by the communication unit 13 via the telephone network H and the network W described later also serve as the determination unit 3, or the telephone network H The CPU (central processing unit) separately connected to any one of the network W, the cloud server N, and the monitoring room A may serve as the determination unit 3.

The determination unit 3 may have a memory for storing the output threshold value T1, the illuminance threshold value T2, the error threshold number T3, and the error count E obtained by counting the number of times the plant illuminance L is equal to or greater than the illuminance threshold value T2. It is also possible to provide a function of clearing (counting to 0 (zero) or resetting) the number of errors E counted.
Note that the error threshold number T3 described later may be one. In this case, if the plant illuminance L is equal to or greater than the illuminance threshold T2 while the power control output value M is equal to or less than the output threshold T1, The determination unit 3 determines that the solar power plant P has an abnormality.
That is, the determination unit 3 indicates that it is possible to determine whether or not the photovoltaic power plant P is abnormal without using the error count E and the error threshold number T3.
In addition, the determination unit 3 determines whether there is an abnormality in the solar power plant P only during a predetermined time period (for example, from 9:00 am to 3:00 pm (15:00)). Also good.

The determination unit 3 receives, as a digital value, an output voltage corresponding to the plant illuminance L and an output voltage corresponding to a power converter output value (power control output current value, etc.) M from the signal conversion unit 12 described later. It may be converted from the digital value of the output voltage how many lux [lx] the actual plant illuminance L and how many amperes [A] the actual power converter output current value M is.
In addition, the determination unit 3 may directly input an illuminance sensor 2 or an analog signal (output voltage or the like) from the measurement unit 11 described later, but the illuminance sensor 2 digitized through a signal conversion unit 12 described later. Alternatively, an output voltage from the measurement unit 11 may be input.
The determination unit 3 outputs the determination result of the presence or absence of abnormality based on the plant illuminance L while the power converter output value M is equal to or less than the output threshold T1 to the communication unit 13 described later.

By having such a determination unit 3 and the illuminance sensor 2 described above, it is not necessary to use a dimming means as in Patent Document 1, and the labor and burden for monitoring the photovoltaic power plant P can be reduced. (“Reducing the monitoring burden”) and there is no reduction in the amount of power generated by the dimming means.
In addition to this, since the presence or absence of abnormality is determined based on the current value from the power conditioner C, the entire photovoltaic power plant P including any solar cells D can be monitored ("" Overall monitoring of the plant ").

<Measurement unit 11>
As shown in FIG. 1, the measurement unit 11 measures a power condition output value M including at least one value of current, voltage, and power from the power conditioner C.
The “power converter output value M including at least one value among the current, voltage, and power from the power conditioner C” means at least one of the current, voltage, and power in the alternating current output from the power conditioner C. This value is referred to as a “power converter output value M”.

The measurement unit 11 may have any configuration as long as it can measure the power converter output value M. For example, an annular (through-type, clamp-type, etc.) ammeter (AC ammeter, current transformer), winding type A current transformer may be used.
In the case of an open / close through-type current transformer or a clamp-type current transformer, the output side (cable on the output side) of the power conditioner C is cut and the measuring unit 11 is inserted (connected). It is not necessary and can be retrofitted to an existing photovoltaic power plant P (power conditioner C).

Further, the measuring unit 11 is configured to connect an AC shunt (AC shunt (resistance and inductance connected in series and capacitance connected in parallel)) to the output side (output side cable) of the power conditioner C. The current value may be obtained from the voltage value at both ends of the AC shunt.
In addition, the measuring unit 11 may be an AC voltmeter or an AC wattmeter connected to the output side of the power conditioner C, or a current transformer (AC ammeter), an AC voltmeter, or AC power. You may combine at least 1 of a total.

Hereinafter, the measurement unit 11 is mainly described as an annular (ring-shaped) current transformer.
An annular current transformer (hereinafter referred to as a current transformer) 11 can detect a current value (power conditioner output current value) M flowing through a cable on the output side of the power conditioner C in a non-contact manner. A current sensor that suppresses power loss and outputs a voltage that is proportional to the power converter output current value M from the power conditioner C.

The current transformer 11 may have any configuration as long as the power converter output current value M from the power conditioner C can be measured. For example, the current transformer 11 may have a configuration having a Hall element (Hall element method).
In addition, the current transformer 11 is a current transformer (CT) system, an air core coil (Rogowski coil) system without a core, a flux gate system, an AC zero magnetic flux control system, an AC / DC magnetic flux control system, an instrument system. It doesn't matter.
Hereinafter, the current transformer 11 will be mainly described as being a Hall element type.

The hall element type current transformer 11 has a core (iron core) formed in a ring shape and a hall element inserted in a gap (gap) provided in the iron core.
The current transformer 11 passes the cable on the output side of the power conditioner C through the center of the hole of the ring-shaped iron core, and the current flows through the cable on the output side of the power conditioner C to cope with the magnetic flux generated around the cable. By outputting the measured voltage from the Hall element, it is possible to measure the current value (power-conversion output current value) M flowing through the output-side cable of the power conditioner C.

Further, the ring-shaped iron core of the current transformer 11 may be configured so that the ring can be opened and closed. The trouble of mounting (retrofitting) to the output side cable from the power conditioner C is from the power conditioner C. The current transformer 11 having a fixed relative position / orientation with respect to the cable is much lower than the trouble of temporarily cutting the cable from the power conditioner C and installing it in the meantime. It can be said that this contributes to improving the efficiency of attachment, particularly retrofit, and cost reduction.
In addition, the current transformer 11 has temperature characteristics, current detection characteristics based on the input voltage, and offset (unbalanced voltage (zero voltage) output when no current flows through the cable from the power conditioner C). The output voltage correction and / or A / D conversion based on these characteristics may be performed collectively by the signal conversion unit 12 described later.

In this case, each current transformer 11 only needs to output raw data (data signal) to the signal converter 12.
Accordingly, it is not necessary to attach an element for performing A / D conversion or correction to each current transformer 11, and the cost of each current transformer 11 can be reduced, and at the same time, the number of current transformers (which can be measured). It can be said that it becomes easy to increase the number of inverters C).

Furthermore, the current transformer 11 may be connected via a variable resistor (varistor), or the grant terminal of the current transformer 11 may be grounded to the ground.
These varistors and grounding can suppress the effects of lightning (lightning surge).

The measuring unit 11 such as a current transformer may be provided in any way as long as it can measure the power converter output value M including at least one value among the current, voltage, and power from the power conditioner C.
For example, the AC current collection box B described above may be provided with one or a plurality of measuring units 11, thereby measuring each power conditioner output value M even when having a plurality of power conditioners C. If the measuring unit 11 is provided, the plurality of measuring units 11 can be easily read together.
Although it is not necessary to attach an element for A / D conversion or correction to each measurement unit (current transformer) 11, naturally, an element for A / D conversion or correction is attached. May be.

<Signal converter 12>
As shown in FIG. 1, the signal processing unit 12 converts the analog signals from the illuminance sensor 2 and the measurement unit 11 described above into digital values (specific plant illuminance L and power converter output value M), and after the conversion. Are output to the determination unit 3 described above.
The signal processing unit 12 A / D-converts analog values such as a voltage value proportional to the plant illuminance L from the illuminance sensor 2 and a voltage value proportional to the power converter output value M such as a current value from the measurement unit 11. Digital value.

In addition, the signal conversion unit 12 receives corrections of the visible relative spectral response characteristics, the oblique incident light characteristics, the temperature characteristics, and the like of the illuminance sensor 2, the temperature characteristics of the measurement unit (current transformer) 11, and the like. Although there are current detection characteristics by voltage, offset, etc., the output voltage may be corrected based on these characteristics.
After performing the A / D conversion and correction described so far, the signal conversion unit 12 converts the output voltage corresponding to the plant illuminance L from the illuminance sensor 2 and the power output value M such as the current value from the measurement unit 11. The digital value of the corresponding output voltage is output to the determination unit 3 described above.

In the graphs shown in FIGS. 5B, 5C, 6B, 6C, and 15 to 18, the vertical axis is described as “illuminance sensor (mV)”, and the horizontal axis Is described as “power generation current (mV)”, and the output voltage corresponding to the plant illuminance L and the output voltage corresponding to the power control output value (power control output current value) M are digital values from the signal conversion unit 12. Are output to the determination unit 3.
Here, the “illuminance sensor (mV)” on the vertical axis means a voltage value corresponding to the plant illuminance L output from the illuminance sensor 2, and the “power generation current (mV)” on the horizontal axis means the power condition. It means a voltage value corresponding to a power-con output current value (power-con output value) M output from the C.

As described above, the output voltage corresponding to the plant illuminance L output from the signal converter 12 and the digital value of the output voltage corresponding to the power converter output value (power converter output current value, etc.) M are the output voltages. The determination unit 3 may convert how many lux [lx] corresponds to the actual plant illuminance L and how many amperes [A] correspond to the actual power converter output current value M. .
On the other hand, if it is clear how many lux [lx] the digital value output from the signal converter 12 corresponds to the plant illuminance L, or how many amperes [A] the power converter output current value M corresponds to, Instead, the determination unit 3 may determine whether there is an abnormality with the digital value of the voltage output from the signal conversion unit 12 as it is.

<Communication unit 13>
As shown in FIGS. 1 and 2, the communication unit 13 communicates the determination result of the presence / absence of abnormality to the photovoltaic power plant P (power conditioner C) of the determination unit 3 to the outside of the monitoring system 1. .
Although it can be said that the communication unit 13 includes the monitoring system 1, when the solar power generation plant P includes the monitoring system 1, the solar power generation plant P naturally includes the communication unit 13. It can also be said.

The communication unit 13 may have any configuration as long as it can communicate the determination result of the abnormality of the photovoltaic power plant P to the outside. For example, the telephone network H is distributed to SMS (Short Message Service). And the structure which communicates the judgment result of the presence or absence with respect to the photovoltaic power plant P to the user (user) U (user's U user terminal etc.) of the photovoltaic power plant P may be sufficient (FIG. 2 (a)). reference).
The user U of the solar power generation plant P may be any person who uses the solar power generation plant P. For example, a business owner (business operator (corporate, individual), the business operator is a corporation). As long as there is an employee, it may be U1 or a management company (manager (corporate, individual), U2 if the manager is a corporation) U2.

In addition, the communication unit 13 sends an e-mail (e) to the above-described user U, the cloud server N, the monitoring room A, and the like described above from the telephone network H via the network W such as the Internet, LAN, MAN, and WAN. -mail, e-mail) The distribution of the determination result of the presence / absence of abnormality with respect to the photovoltaic power plant P (see FIG. 2B) or the photovoltaic power plant on the web site on the cloud server N described later A configuration may be used in which the determination result of whether there is an abnormality with respect to P is uploaded and the user U browses from a user terminal or the like.
Here, the cloud server N, the user U (user terminal), and the monitoring room will be described below.

<Application server (cloud server) N>
As shown in FIG. 2B, the cloud server N is connected to the monitoring system 1 (communication unit 13) or the user U (user) via the network W such as the Internet, LAN, MAN, WAN from the telephone network H. Terminal) and a server connectable to the monitoring room A.
The cloud server N uses the monitoring system 1 for the photovoltaic power plant P (power conditioner C) to determine whether there is an abnormality, data such as the amount of power generation itself, and the control content for the photovoltaic power plant P (ON, OFF, power generation suppression). Etc.) and can be connected from both the user U (user terminal).
The cloud server N may be configured not only with a single computer but also with a LAN (cloud LAN) including a plurality of computers, such as the plant LAN described above.

Note that the cloud server N is considered to be a part of a network W that is an aggregate of a telephone network H, a LAN, and the like, and the network W such as the telephone network H integrates a plurality of computers in an integrated manner. It is treated (virtualized) as one computing resource (network, server, storage, application, service).
Therefore, the determination result of the presence or absence of abnormality of the photovoltaic power plant P, the data such as the amount of power generation, and the control content for the photovoltaic power plant P are placed on the cloud server N and at the same time the network W (phone network H). It can be said that it is placed above.

Moreover, since the cloud server N is virtualized, it can be said that the communication system 1 of the present invention is a “grid system”.
Note that the “grid system” in the present invention is defined by “JIS-X-7301: 2010”, which requires necessary resources without being aware of the physical location and hardware of resources such as computers, storage, and networks. A system that can be used as often as necessary and is a heterogeneous and / or geographically distributed system that integrates multiple computer resources using virtualization technology.

In addition, between the cloud server N and the monitoring system 1, between the cloud server N and the user U (user terminal), and between the cloud server N and the monitoring room A, a network W (telephone network) in which determination results and control contents are placed by the cloud server N. H) A provider contract is made with a provider that provides a service that secures a place on the Internet (provider of an Internet connection service).
The cloud server N may have any configuration as long as these functions are realized.

The cloud server N may have an FTP server and be connected to the network W (telephone network H) via a firewall.
In addition to the firewall described above, the cloud server N may have anti-virus software (application software that detects, removes, and disables computer viruses), or has either a firewall or anti-virus software. It is also good that you are doing.
It can be said that it is a monitoring system including the cloud server N described so far and the monitoring system 1 described above.

<User U (user terminal)>
As shown in FIG. 2, the user terminal of the user U displays the determination result of the presence / absence of abnormality by the monitoring system 1 for the solar power plant P (power conditioner C), and the solar power plant P input by the user U. It is a terminal that transmits the control content to.
The user terminal can be directly connected to the cloud server N via the telephone network H, or the cloud server N or the monitoring system 1 (communication unit) from the telephone network H via the network W such as the Internet, LAN, MAN, WAN. 13) A terminal that can be connected to the monitoring room A.
Further, the user terminal of the user U may be configured to be directly connectable to the monitoring system 1 via the telephone network H.

If these are realized, the user terminal of the user U can input the display means by which the user U can view the determination result of the photovoltaic power plant P far away, and the control content to the photovoltaic power plant P. Any configuration may be used as long as there is a means. For example, a notebook PC, a mobile phone, a smartphone, a tablet terminal, a PDA (personal digital assistant), etc. may be used in addition to a desktop PC.
The user terminal is not only composed of one desktop PC as described above, but also a plurality of desktop PCs, notebook PCs, mobile phones, smartphones, tablets, etc. as in the above-mentioned cloud LAN. You may comprise LAN (user LAN) which consists of a terminal, PDA, etc.
Further, the user terminal has a browser for referring to (browsing) a predetermined URL (Web page) on the telephone network H and the network W (cloud server N) including the telephone network H, or has an FTP client. May be.

<Monitoring room A>
As shown in FIG. 2, the monitoring room A has a configuration in which an operator (monitoring person) monitors display means that can browse a judgment result of the presence / absence of abnormality by the monitoring system 1 for the photovoltaic power plant P (power conditioner C). It has become.
Thereby, in addition to the cloud server N, a flexible response | compatibility by a person is also attained, and the determination precision of the abnormality presence or absence with respect to the solar power generation plant P can be improved more correctly.

<Storage unit>
The storage unit stores the power conditioner output value M from the power conditioner C and the plant illuminance L from the illuminance sensor 2 (not shown).
The storage unit may have any configuration as long as it can store the power control output value M and the plant illuminance L. For example, the storage unit stores the power control output value M and the plant illuminance L (memory, hard disk, DVD, CD). Or other storage media).

<Solar power plant P under various conditions>
The solar power generation plant P described so far performs power generation under various conditions (conditions) such as a sunny day, a cloudy day, a rainy day, and a typhoon day.
4-9, the power conditioner output value M of the photovoltaic power plant P under various conditions, the plant illumination intensity L, etc. are shown.

Among these, in FIG. 4 (clear day) and FIG. 5 (a) (relatively clear day), the solar power plant P is normal and the illuminance is increased (brighter). The case where the output current value (power-conversion output value M) of the power conditioner C is reduced is shown.
That is, under a predetermined environment such as a sunny day, there is a portion where the power conditioner output value M of the power conditioner C is not proportional to the plant illuminance even if there is no abnormality in the photovoltaic power plant P. If the amount of power generation (power converter output value M) decreases while the plant illuminance L) increases, it is determined that there is an abnormality, which causes false alarms.
This is because, as shown in FIG. 5B, the correlation coefficient between the power condition output value M and the plant illuminance L in the entire power condition output value (output current value from the power conditioner C) M is 0.76. I understand that.
On the other hand, as shown in FIG. 5C, the power condition output value M in the range where the power condition output value (output current value from the power conditioner C) M is equal to or less than the output threshold T1 (here, 5.0A) The correlation coefficient with the plant illuminance L is 0.92, and it can be seen that the power converter output value M and the plant illuminance L have a positive correlation.
Therefore, in the range below the output threshold T1 having a positive correlation between the power converter output value M and the plant illuminance L, the expected plant illuminance L is obtained from the power control output value M and compared with the actually measured plant illuminance L. Thus, it is possible to determine whether there is an abnormality in the photovoltaic power plant P (power conditioner C).

As shown in (a) to (c) of FIG. 6, even if it is not a clear day but a cloudy day or a rainy day, at least in the range of the output threshold T1 or less, It is the same that the plant illuminance L has a positive correlation.
Specifically, as shown in FIG. 6 (a), in the environment of a cloudy day or a rainy day, the photovoltaic power plant P passes through the daytime, and the power conditioner output value (from the power conditioner C). Output current value) M is small.
Therefore, since the power converter output value M is in the vicinity of the output threshold value T1 or in the range of the output threshold value T1 or less, as shown in FIG. As shown in FIG. 6C, the power control output value M and the plant illuminance are within the range where the power control output value M is less than or equal to the output threshold value T1 (5.0 A). The correlation coefficient with L is 0.97.
Therefore, regardless of the environment (sunny day, cloudy day, rainy day, typhoon day, etc.) where the photovoltaic power plant P is located, there is a positive correlation between the power converter output value M and the plant illuminance L. In the range below the relevant output threshold T1, it is possible to determine whether there is an abnormality in the photovoltaic power plant P as compared with the actually measured plant illuminance L.

The power conditioner output value M, the plant illuminance L, and the like when the presence / absence of abnormality of the photovoltaic power plant P based on the plant illuminance L is not determined under other conditions are also described. FIG. 7 shows the power converter output value M, plant illuminance L, etc. of the photovoltaic power plant P (no abnormality in this photovoltaic power plant P) for three days from August 17, 2014 to August 20, 2014. ing.
During these days when the sun is rising, the power control output value (power control output current value) M does not decrease, and no false alarm (false notification) has occurred due to the decrease of the power control output value M. .

FIG. 8 shows the power conditioner output value M, plant illuminance L, etc. of the photovoltaic power plant P (no abnormality in this photovoltaic power plant P) for three days from August 8, 2014 to August 10, 2014. ing.
During these three days, the power converter output value (power converter output current value) M has decreased during the day due to typhoons on any day, and the power converter output value M has no abnormality in the solar power plant P. There is a misinformation about the decline.
In FIG. 8, when it is determined that there is an abnormality in the photovoltaic power plant P, uploading to the web site on the cloud server N, or “output (abnormality is This means that a signal indicating that it is present is output), and the same applies to FIGS.
In addition, the direction of the illuminance sensor 2 is changed (on August 8, 2014, the light receiving unit 2a of the illuminance sensor 2 that was originally oriented in the zenith direction (substantially vertically upward) is moved downward (substantially vertically downward). Or on August 10, 2014, the light receiving unit 2a of the illuminance sensor 2 is oriented in a substantially horizontal direction and the direction is directed north)), but the photovoltaic power generation plant based on the plant illuminance L It is not judged whether P is abnormal.

FIG. 9 shows the power conditioner output value M, plant illuminance L, and the like of the photovoltaic power plant P on August 16, 2014 (the photovoltaic power plant P has no abnormality).
This day, due to the influence of rain, the power control output value (power control output current during the daytime (particularly from about 11:08 am on August 16, 2014 to 2:58 pm (14:58)) Value) M has fallen, and although there is no abnormality in the photovoltaic power plant P, a false alarm has occurred because the power converter output value M has fallen.

<Monitoring program>
As described above, the photovoltaic power plant P is placed in various environments such as a sunny day, a cloudy day, a rainy day, and a typhoon day. It will be understood that there is a positive correlation between the value M and the plant illuminance L, and the monitoring program S using this will be described below.
The monitoring program S in the monitoring system 1 (determination unit 3) of the present invention is based on the plant illuminance L while the power conditioner output value M is equal to or less than the output threshold value T1. Any program can be used as long as it can be determined whether or not there is an abnormality.
For example, the following monitoring program (monitoring algorithm) S may be executed by the determination unit 3 (CPU).

<First embodiment of monitoring program (illuminance threshold value fixing program) S>
As shown in FIG. 10, the first embodiment of the monitoring program S is a program (illuminance threshold fixing program S) that determines whether there is an abnormality in the photovoltaic power plant P by fixing the illuminance threshold T2.
The monitoring system 1 (determination unit 3) that executes the illuminance threshold value fixing program S of the present invention determines whether the photovoltaic power plant P is abnormal.
The flow of the illuminance threshold value fixing program S will be described below (steps S-1 to S-6, S-21 to S-23, S-31).

Examples of parameters used in the illuminance threshold fixing program S are shown in Table 1 below.
The output threshold value T1 “5.0A” in Table 1 corresponds to the output voltage value “211 mV” from the measurement unit 11, and the illuminance threshold value T2 “2500 (?) Lux [lx]” is the illuminance sensor 2. Corresponds to an output voltage value of “300 mV”.
The output threshold T1 may be “2.5 A (≈100 mV)”.

<Step S-1>
When the illuminance threshold value fixing program S is started in the monitoring system 1 (determination unit 3), the measurement start time ((A) in Table 1) to the measurement end time ((B) in Table 1) are determined. At every measurement interval ((C) in Table 1), at least the power conditioner output value M of the power conditioner C is measured by the measuring unit 11 (step S-1).
Note that the illuminance sensor 2 may measure the plant illuminance L in the photovoltaic power plant P at every measurement interval ((C) in Table 1).

<Step S-2>
In the monitoring system 1 (determination unit 3), if the power converter output value M measured in step S-1 is equal to or less than the output threshold value T1 (T1 in Table 1), the process proceeds to step S-3 described below. If the output value M is larger than the output threshold value T1, the process proceeds to step S-21 described later (step S-2).

<Step S-21>
In the monitoring system 1 (determination unit 3), if the stored error count E is equal to or greater than the error threshold number T3, the process proceeds to step S-22 described below. Conversely, if the error count E is smaller than the error threshold number T3. Then, the process proceeds to Step S-23 described later (Step S-21).

<Step S-22>
In the monitoring system 1 (determination unit 3), the stored error count E is cleared (reset to 0), and the web site or SMS on the cloud server N is transmitted to the user U or the monitoring room A via the communication unit 13. It communicates (notifies) “normal” or “normal return” by distribution or e-mail distribution, and then returns to step S-1 described above (step S-22).

<Step S-23>
In the monitoring system 1 (determination unit 3), the stored error count E is cleared (reset to 0), and to the user U or the like via the communication unit 13, a web site on the cloud server N, SMS distribution, or electronic It communicates (notifies) “normal” or “normal operation” by mail delivery, and then returns to step S-1 described above (step S-23).

<Step S-3>
In the monitoring system 1 (determination unit 3), the plant illuminance L measured in step S-1 (or the plant illuminance L in the photovoltaic power plant P in step S-3 is measured by the illuminance sensor 2). If the plant illuminance L is smaller than the illuminance threshold T2, the process proceeds to step S-31 described later (step S-3).

<Step S-31>
In the monitoring system 1 (determination unit 3), the stored error count E is cleared (reset to 0) and “measurement is impossible (the power converter output value M from the power conditioner C in the photovoltaic power plant P cannot be measured). ”Is then determined, and then the process returns to step S-1 described above (step S-31).
There is no need to communicate with the user U or the monitoring room A (in this case, “-(hyphen)” may be displayed on the display means of the user terminal of the user U), but the user U or the like. The communication unit 13 may communicate (notify) “-(hyphen)” or “impossible to measure” via a web site on the cloud server N, SMS delivery, or email delivery.

<Step S-4>
In the monitoring system 1 (determination unit 3), a value obtained by adding 1 to the stored error count E is stored as a new error count E, and then the process proceeds to Step S-5 described later (step S-4). .

<Step S-5>
In the monitoring system 1 (determination unit 3), if the stored error count E is equal to or greater than the error threshold number T3, the process proceeds to step S-6 described below, and conversely if the error count E is smaller than the error threshold number T3. The process returns to step S-1 described above (step S-5).

<Step S-6>
In the monitoring system 1 (determination unit 3), “output (a signal indicating that there is an abnormality has been output) to the user U or the like via the communication unit 13 on the web site on the cloud server N, SMS distribution, or e-mail distribution. ) ”Or“ output reduction ”(notify), and then return to the above-described step S-1 (step S-6).

<Photovoltaic power plant P when the monitoring program S of the first embodiment is executed>
11 and 12 show a state in which the monitoring program (illuminance threshold value fixing program) S of the first embodiment described above is executed by the photovoltaic power plant P. FIG.
FIG. 11 shows the power conditioner output value M, plant illuminance L, and the like of the photovoltaic power plant P on August 27, 2014 (the photovoltaic power plant P has no abnormality).
On this day, during the day when the sun is rising, the power control output value (power control output current value) M does not decrease, but the measurement unit 11 and the illuminance sensor 2 are intentionally operated for a predetermined time. Thus, when the illuminance threshold value fixing program S was executed, it was confirmed whether the determination of the presence or absence of abnormality of the photovoltaic power plant P (power conditioner C) was correct in the following two cases.

<Case where power control output value (power control output current value) M is “0.0 A” and plant illuminance L is “2500 lux [lx]”>
As a specific case, it is measured at every measurement interval (C) of 10 minutes in the measurement unit (current transformer) 11 from 11:38 am on August 27, 2014 to around 12:28 noon. The power control output value (power control output current value) M from “CH01” was intentionally set to 0.0 A, and the voltage corresponding to the plant illuminance L from the illuminance sensor 2 was intentionally set to 300 mV.
Although the measurement interval (C) is 10 minutes, there is no particular limitation as a matter of course, and any value such as 5 minutes, 1 minute, 30 minutes, or 1 hour may be used.

More specifically, every 10 minutes of the measurement interval (C), first, at 11:38 am on August 27, 2014, the power conditioner output value measured in step S-1 in the illuminance threshold fixing program S It is determined in step S-2 that M “0.0A” is equal to or less than the output threshold T1 “5.0A” shown in Table 1, and the process proceeds to the next step S-3.
In step S-3 where the process has shifted, the plant illuminance L “2500 lux [lx] (≈300 mV)” is greater than or equal to the illuminance threshold T2 “2500 lux [lx] (≈300 mV)” shown in Table 1. The determination is made at S-3, and the process proceeds to the next step S-4.
In step S-4 where the process has moved, 1 is added to the error number E which was initially "0 (zero)", the error number E becomes "1", and the process moves to the next step S-5.
In step S-5 where the process has shifted, the error count E “1” is smaller than the error threshold number T3 “5” shown in Table 1, so the process returns to step S-1.
At this point, the illuminance threshold value fixing program S has not yet determined that there is an abnormality in the photovoltaic power plant P, so in the web site on the cloud server N, SMS distribution, e-mail distribution, etc. The user U is continuously notified of “normal”.

Next, at 11:48 am on August 27, 2014, similarly, the power converter output value M “0.0A” measured in step S-1 of the illuminance threshold fixing program S is the output threshold. It is determined in step S-2 that T1 is “5.0 A” or less, and in the next step S-3, the plant illuminance L “2500 lux [lx]” is equal to or greater than the illuminance threshold T2 “2500 lux [lx]”. Is determined, and the process proceeds to the next step S-4.
In step S-4 where the process has moved, 1 is added to the error count E that was “1”, so that the error count E becomes “2”. In the next step S-5, the error count E “2” Since the error threshold number T3 is smaller than “5”, the process returns to step S-1.
At this time, the user U is continuously notified of “normal” on the web site on the cloud server N or the like.

The same applies to 11:58 am and 12:08 on August 27, 2014, and the error count E becomes “3” or “4” after steps S-1 to S-4. Since the error threshold value T3 is smaller than “5” at −5, the process returns to step S-1, and the user U is notified of “normal” at the web site or the like on the cloud server N.
However, at 12:18 noon on August 27, 2014, the error count E becomes “5” through steps S-1 to S-4. In step S-5, the error threshold number T3 “5” is displayed for the first time. Thus, the process moves to the next step S-6.
In step S-6 where the process has moved, the user U is notified of "output" by web site on the cloud server N, SMS distribution, e-mail distribution, etc., and then the process returns to step S-1. .

Next, at 12:28 noon on August 27, 2014, similarly, the number of errors E becomes “6” through steps S-1 to S-4. In step S-5, the error threshold number T3 “ Therefore, the user U is continuously notified of “output” at the web site on the cloud server N in step S-6, and the process returns to step S-1.
However, at 12:38 noon on August 27, 2014, the power converter output value (power converter output current value) M from “CH01” measured in step S-1 is changed to the measurement unit (current transformer) 11. In step S-2, it is determined that the value is larger than the output threshold T1 “5.0A”, and the process proceeds to the next step S-21.
In step S-21, the error count E “6” is equal to or greater than the error threshold number T3 “5” in step S-21. Therefore, in step S-22, the error count E “0” is reset to the error count E “0”. After the user U is notified of “normal” at the web site or the like, the process returns to step S-1.

<Case where power control output value (power control output current value) M is “0.0 A” and plant illuminance L is “0 lux [lx]”>
As another specific case, a measurement interval (current transformer) 11 of 10 minutes between 12:58 on August 27, 2014 and 1:58 pm (13:58) The power converter output value (power converter output current value) M from “CH01” measured every (C) is deliberately set to 0.0 A, and the voltage corresponding to the plant illuminance L from the illuminance sensor 2 is now Intentionally, it was set to 0 mV or more.

First, at 12:58 noon on August 27, 2014, the power converter output value M “0.0A” measured in step S-1 in the illuminance threshold fixing program S is the output threshold T1 “5. 0A "or less is determined in step S-2, and the process proceeds to the next step S-3.
In step S-3 where the process has moved, it is determined in step S-3 that the plant illuminance L “0 lux [lx] (= 0 mV)” is smaller than the illuminance threshold T2 “2500 lux [lx] (≈300 mV)”. Next, the process moves to step S-31.
In step S-31 in which the process has moved, the error count E is reset to “0”, and the user U is notified of “− (hyphen)” on the web site or the like on the cloud server N, and then step S- The process returns to 1.
Note that “-(hyphen)” notified to the user U means “measuring impossible”, but if “CH01” is determined to be “measuring impossible”, “CH02” to “CH05” are also displayed. Of course, it should be placed in the same environment as cloudy or rainy.
Therefore, not only “CH01” with the power converter output value M set to “0.0A”, but also “− (hyphen)” meaning “impossible to measure” for other “CH02” to “CH05” is notified to the user U. Is done.
The notification of “-(hyphen)” from “CH01” to “CH05” is not limited to 12:58 noon on August 27, 2014, and then every 10 minutes at regular intervals (C) in 2014 August 27th at 1:08 pm (13:08), 1:18 pm (13:18), 1:28 pm (13:28), 1:38 pm (13:38) Minutes), 1:48 pm (13:48), and 1:58 pm (13:58).

<Case where power control output value (power control output current value) M has fallen below output threshold T1 due to weather>
On the other hand, FIG. 12 shows the power conditioner output value M, plant illuminance L, and the like of the solar power plant P on August 24, 2014 (the solar power plant P has no abnormality).
In FIG. 12, the power control output value (power control output current value) M decreased even during the daytime due to the weather, instead of intentionally operating the measurement unit 11 or the illuminance sensor 2 as in FIG. Even in this case, when the illuminance threshold value fixing program S was executed, it was confirmed whether the determination of the presence or absence of abnormality of the photovoltaic power plant P was correct.

Specifically, between 12:28 noon on August 24, 2014 and around 3:18 pm (15:28), the measurement unit (current transformer) 11 has a measurement interval of 10 minutes (C ), The power output value (power output current value) M from “CH01” measured every time is equal to or less than “5.0 A” of the output threshold T1.
More specifically, every 10 minutes of the measurement interval (C), first, at 12:28 noon on August 24, 2014, the power conditioner output value measured in step S-1 in the illuminance threshold fixing program S In step S-2, M is determined to be equal to or less than the output threshold T1 “5.0A”, and the process proceeds to the next step S-3.
In step S-3 to which the process has moved, it is determined in step S-3 that the plant illuminance L is also smaller than the illuminance threshold T2 “2500 lux [lx] (≈300 mV)”. Next, the process proceeds to step S-31. Move.
In step S-31 in which the process has moved, the error count E is reset to “0”, and the user U is notified of “− (hyphen) over“ CH01 ”to“ CH05 ”at the web site or the like on the cloud server N. ) ", The process returns to step S-1.
The notification of “-(hyphen)” from “CH01” to “CH05” is not limited to 12:28 noon on August 24, 2014, and then every 10 minutes at regular intervals (C) in 2014 It is similarly performed every 10 minutes of the measurement interval (C) from 12:38 noon on August 24 to 3:18 pm (15:28).
Conversely, from 12:28 noon on August 24, 2014 to 3:18 pm (15:28), unless the illuminance threshold value fixing program S is executed by the photovoltaic power plant P, Since the user U is notified that there is an abnormality in the photovoltaic power plant P based only on the decrease in the power converter output value M, it can be seen that the false alarm is avoided.

11 and 12, when the monitoring program (illuminance threshold value fixing program) S is executed in the photovoltaic power plant P, the power conditioner output value M is equal to or less than the output threshold value T1, and the plant illuminance L is equal to or greater than the illuminance threshold value T2. Only when the error count E is equal to or greater than the error threshold number T3, the user U is notified that there is an abnormality in the photovoltaic power plant P. At the same time, the power converter output value M is equal to or less than the output threshold T1, When the plant illuminance L is smaller than the illuminance threshold value T2, it is a decrease due to the weather, so that the user U is not notified that there is an abnormality in the solar power plant P, and thus misreporting of the abnormality determination is suppressed ("Suppression of misinformation" )) And an illuminance sensor (illuminometer) that is less costly than a pyranometer.
That is, according to the monitoring system 1 of the present invention, as in the prior art, on the rainy or cloudy day, the solar power plant P (power conditioner C) is operating normally even though it is operating normally. The notification is not notified, and in the case of a rainy or cloudy day when there is no illuminance above a certain level, the determination is not made darely, so that misinformation can be suppressed.

<Changeable illuminance threshold T2>
Up to this point, the case where the illuminance threshold value T2 is fixed (illuminance threshold value fixing program) has been described. However, the mounting direction of the light receiving unit 2a of the illuminance sensor 2 described above depends on the installation location in the photovoltaic power plant P. It is not always possible to install in the direction (for example, north direction).
For example, FIG. 13 shows the power conditioner output value M, plant illuminance L, etc. of the solar power plant P (the solar power plant P has no abnormality) on August 29, 2014, but at 2:58 pm Minute, the solar power plant P is informed that there is an abnormality.
Further, FIG. 14 shows the power conditioner output value M, plant illuminance L, etc. of the solar power plant P (this solar power plant P has no abnormality) on September 1, 2014. For example, the solar power plant P is informed that there is an abnormality.

That is, since the amount of the light beam entering the light receiving unit 2a of the illuminance sensor 2 also changes depending on the surrounding situation where the solar power plant P is placed and the change of the altitude of the sun in the south, the sunlight by the determination unit 3 It is more preferable to determine or optimize the illuminance threshold T2 having a margin according to the situation, which does not learn by itself during the determination of the presence or absence of abnormality of the power plant P, and can further suppress false alarms.
The output threshold T1 may be fixed even if the rated power or manufacturer of the power conditioner C changes.
Tables 2 to 9 and 11 to 14 are summarized.

<Example 1 of the illumination threshold value T2 determination method>
Example 1 is shown below as a method for determining the illuminance threshold T2 in accordance with the surrounding situation where the solar power plant P is placed, the change in the altitude of the south and middle of the sun, and the operation state.
Table 3 below summarizes the correlation between the power condition output value M and the plant illuminance L for 6 days from August 29 to 31, 2014, September 1, 2, and 6.

As shown in Table 3, when the power converter output value (power converter output current value) M is correlated over the entire range of 0.0A to 25.0A, the minimum value is a phase in the vicinity of 0.7 to 0.9. Although the relationship number has been reached, this indicates that the value of the correlation coefficient becomes worse (lower) on a sunny day (a sunny day).
On the other hand, if the power control output value (power control output current value) M is equal to or less than the output threshold value T1 (5.0 A) that is the determination range, all have a correlation coefficient of 0.9 or more, indicating a strong correlation. You can see (Note that the slope of the regression line varies depending on the installation environment, so adjustment is necessary each time).
From this, if the “output threshold value T1” is determined, it is possible to estimate the approximate value of the “illuminance threshold value T2” at that time.

FIG. 15 is an example of August 31, 2014. If “illuminance threshold value T2” is determined in the blue region (shaded region indicated by α in FIG. 15) in FIG. 15 with respect to “output threshold value T1”. I think that misjudgment can be avoided.
Note that the straight line β in FIG. 15 is obtained by shifting the y-intercept of the regression line y = 2.0485x−14.451 and bringing it to a region where no erroneous determination is made. The straight line is y = 2.0485x + 200.000. Become.
Considering this, for example, it is understood that the illuminance threshold T2 may be set to “6300 lux [lx] (≈400 mV)” with respect to the output threshold T1 of “2.5 A (≈100 mV)”. In addition, since the opportunity of determination will reduce if illumination threshold value T2 is raised, you may obtain | require an optimal value suitably.

<Second Embodiment of Monitoring Program (Correlation Coefficient / Regression Line Program) S ′>
A second embodiment (correlation coefficient / regression line program) S ′ of the monitoring program that causes the monitoring system 1 to execute the first embodiment of the illuminance threshold T2 determination method will be described below.
This second embodiment (correlation coefficient / regression line program) S ′ is shown below instead of steps S-1 and S-3 in the first embodiment (illuminance threshold value fixing program) S of the monitoring program described above. Steps S′-1 and S′-3 are included.

<Step S'-1>
When the correlation coefficient / regression line program S ′ is started in the monitoring system 1 (determination unit 3), the power condition is set at every predetermined measurement interval (for example, 1 hour) from the measurement start time to the measurement end time. The power control output value M of NA C is measured by the measuring unit 11, and the plant illuminance L is measured by the illuminance sensor 2.
These measured power converter output value M and plant illuminance L are recorded in the storage device in the determination unit 3 or the above-described storage unit, and the power control output value M for a certain period (a certain number of times) and the mother of the plant illuminance L at that time. A group is formed (step S′-1).
In addition, since the power condition output value M memorize | stored by this step S'-1 and the plant illumination intensity L at that time cannot be correlated with the plant illumination intensity L in the power condition output value (power condition output current value) M which is too high, for example, The power control output value M when the power control output value M is equal to or less than the output threshold T1 and the plant illuminance L at that time may be stored.
Further, the number of sets of the power control output value M that can be stored and the plant illuminance L at that time is not particularly limited, but at least the number of samples in step S′-3 described later is stored.

<Step S'-3>
In the monitoring system 1 (determination unit 3), if the plant illuminance L measured in step S-1 is equal to or greater than the illuminance threshold T2, the process proceeds to step S-4 described below, and conversely, the plant illuminance L may be smaller than the illuminance threshold T2. Then, the process proceeds to step S-31 described later (step S'-3).
The illuminance threshold T2 used in step S′-3 cannot be calculated until the number of pairs of the stored power conditioner output value M and the plant illuminance L at that time reaches a predetermined number of samples (for example, 30). Therefore, the default illuminance threshold value T2 is used during this period.
When the number of stored power conditioner output values M and the plant illuminance L at that time exceeds the number of samples, the pair of the oldest (earliest stored) power conditioner output value M and the current plant illuminance L The illuminance threshold value T2 is always calculated from the set of the latest power conditioner output value M (30, etc.) and the plant illuminance L at that time.
In the calculation of the illuminance threshold T2, when a set of a new power conditioner output value M and the plant illuminance L at that time is stored, a correlation coefficient is first obtained. However, a set of a power converter output value M equal to or lower than the output threshold T1 (for example, 5.0 A) and the plant illuminance L at that time is a target, and a set of the power control output value M equal to or lower than the output threshold T1 and the plant illuminance L at that time. However, when updated (newly stored), the correlation coefficient is obtained.
Only when this correlation coefficient is a predetermined value (for example, 0.9) or more, a regression line is obtained, and based on this regression line, a plant illuminance L (estimated plant illuminance L) estimated with respect to the power converter output value M is obtained. ') Ask.
A value obtained by adding a certain margin to the estimated plant illuminance L ′ (for example, a straight line β brought to a region in which the y-intercept of the regression line in FIG. 15 is not erroneously determined) is set as the illuminance threshold.
Specifically, as described above, if the output threshold T1 is “2.5 A (≈100 mV)”, the illuminance threshold T2 may be set to “6300 lux [lx] (≈400 mV)”. Similarly, if the voltage corresponding to the output threshold T1 is “150 mV (≈3.75 A)”, the voltage corresponding to the illuminance threshold T2 may be set to about “500 mV (eg, 7875 lux [lx])”. I understand that.

It can be said that this step S′-3 optimizes the illuminance threshold T2 for the power conditioner output value M in accordance with the long-term change in the plant illuminance L after the installation of the photovoltaic power plant P.
The illuminance threshold value T2 when the monitoring program (correlation coefficient / regression line program) S ′ of the second embodiment is executed is determined while the determination unit 3 determines whether the photovoltaic power plant P is abnormal. It can also be said that the threshold value can be changed, and in the environment where the photovoltaic power plant P is placed (the direction in which the illuminance sensor 2 is mounted (in the vertical direction such as the horizontal direction, the vertical direction, the diagonal direction, the direction, etc. ), The illuminance threshold T2 can be optimized according to the height of the sun's south and middle altitudes.
The other steps in the monitoring program (correlation coefficient / regression line program) S ′ of the second embodiment are the same as steps S-2 and S-4 in the monitoring program (illuminance threshold value fixing program) S of the first embodiment. The same as S-6, S-21 to S-23, and S-31.

<Examples of other correlation coefficients, regression lines, and estimated plant illuminance L '>
In addition, the regression line was calculated | required also on days other than the example of August 31, 2014 shown in FIG.
16 to 18 are power control output values from the photovoltaic power plant P at the installation direction and the installation location of the illuminance sensor 2 shown in (a) to (c) of FIG. 3 on days other than August 31, 2014. It is a regression line based on the data of M and plant illuminance L.
Specifically, FIG. 16 (FIG. 3A) shows the light receiving unit 2a (normal line of the light receiving surface) of the illuminance sensor 2 in a substantially horizontal direction with respect to the photovoltaic power plant of the A power plant (light receiving unit). In FIG. 17 (FIG. 3B), the light receiving unit 2a of the illuminance sensor 2 is set in a substantially vertical direction with respect to the photovoltaic power plant of the A power plant. 18 (Fig. 3 (c)) is a case where the solar power plant at the installation site of the B power plant is This is a case where the light receiving portion 2a of the illuminance sensor 2 is oriented in a substantially horizontal direction (direct sunlight is difficult to hit the light receiving portion 2a).

From FIG. 16 to FIG. 18, the power converter output value (power converter output current value) M is equal to the output threshold T1 “5. When viewed in the range of “0A” or less, it can be said that there is a strong correlation with the plant illuminance L from the illuminance sensor 2.
Also, comparing the regression lines in FIGS. 16 to 18, the slopes of the respective lines tend to be somewhat different, and it can be said that the illuminance received by the illuminance sensor 2 varies depending on the mounting direction and the installation location.
When the plant illuminance L with respect to the power converter output value (power converter output current value) M of “2.5 A (≈100 mV)” is predicted using the regression lines of FIGS. 16 to 18, in FIG. 17 is between 190 mV and 340 mV, and in FIG. 18 is between 70 mV and 120 mV. Regardless of the installation location, the variation in FIGS.
From this, it can be said that it is preferable to attach the light receiving portion 2a of the illuminance sensor 2 in a substantially horizontal direction.

As shown in FIGS. 16 to 18, since it is clear that there is a correlation between the power conditioner output value M and the plant illuminance L, if the output threshold value T1 (for example, 5.0 A) or less, the pyranometer It can be said that the illuminance sensor 2 can also make a sufficient judgment.
Furthermore, the output threshold value T1 may be appropriately set to about 2.0 A from the data analysis of FIGS. 16 to 18 and the like, and may be set to 2.5 A, for example.
In addition, although the photovoltaic power plant P is not generating power at night, a little current (for example, 0.5 A) flows to the output side of the power conditioner C. It can be said that this is the current consumed by the circuit (or the current flowing from the system).
Therefore, the output threshold T1 may be equal to or greater than the value of current flowing at night (for example, 0.5 A).
When the output voltage corresponding to the plant illuminance L from the illuminance sensor 2 is small, the resistance value of the resistor used when converting the current from the photodiode into the voltage in the illuminance sensor 2 is changed. It can be said that it is better to increase the output voltage corresponding to the illuminance L from 2 times to 5 times.

<Example 2 of the illumination threshold value T2 determination method>
As a method for determining the illuminance threshold T2, a second embodiment in which the calculation is further simplified than the first embodiment will be described below.
The second embodiment of the method for determining the illuminance threshold T2 is a method for obtaining the moving average of the ratio between the power conditioner output value M and the plant illuminance L.

<Third embodiment of monitoring program (moving average program) S ">
A third embodiment (moving average program) S ″ of a monitoring program that causes the monitoring system 1 to execute the second embodiment of the illuminance threshold T2 determination method will be described below.
In this third embodiment (moving average program) S ″, instead of steps S-1 and S-3 in the first embodiment (illuminance threshold value fixing program) S of the monitoring program described above, the following step S ″ − 1, S ″ -3.

<Step S "-1>
When the moving average program S ″ is started in the monitoring system 1 (determination unit 3), the power conditioner C is connected at every predetermined measurement interval (for example, 1 hour) from the measurement start time to the measurement end time. The output value M is measured by the measuring unit 11, and the plant illuminance L is measured by the illuminance sensor 2.
A ratio obtained by dividing the measured power converter output value M by the plant illuminance L at that time is recorded in the storage device in the determination unit 3 or the storage unit described above, and the power control output value M for a certain period (a certain number of times) A population of plant illuminance L at that time is formed (step S ″ -1).
In addition, since the power condition output value M memorize | stored in this step S "-1 and the plant illumination intensity L at that time cannot correlate with the plant illumination intensity L in the very high power condition output value (power condition output current value) M, for example, The ratio of the plant illuminance L at that time to the power condition output value M when the power condition output value M is equal to or less than the output threshold value T1 may be stored.
Further, the number of ratios of the plant illuminance L to the storable power conditioner output value M is not particularly limited, but at least the number of samples in step S ″ -3 described later is stored.

<Step S "-3>
In the monitoring system 1 (determination unit 3), if the plant illuminance L measured in step S-1 is equal to or greater than the illuminance threshold T2, the process proceeds to step S-4 described below, and conversely, the plant illuminance L may be smaller than the illuminance threshold T2. Then, the process proceeds to step S-31 described later (step S "-3).
The illuminance threshold T2 used in step S ″ -3 cannot be calculated until the number of ratios of the plant illuminance L to the stored power conditioner output value M reaches a predetermined number of samples (for example, 10). Uses the default illuminance threshold T2.
When the number of ratios of plant illuminance L to stored power conditioner output value M exceeds the number of samples, the ratio of plant illuminance L to the oldest (earliest stored) power conditioner output value M is discarded and always updated. The illuminance threshold value T2 is calculated from the ratio of the plant illuminance L to the power conditioner output value M of the number of samples (such as 10).
In the calculation of the illuminance threshold T2, when the ratio of the plant illuminance L to the new power conditioner output value M is stored, a moving average is obtained based on the ratio of the latest number of samples (such as 10). However, the ratio of the plant illuminance L to the power converter output value M below the output threshold T1 (for example, 5.0 A) is the target, and the ratio of the plant illuminance L to the power converter output value M below the output threshold T1 is updated ( When it is newly stored), a moving average is obtained.
Based on the moving average of the obtained ratio, a plant illuminance L (estimated plant illuminance L ′) estimated for the power converter output value M is obtained.
A value obtained by adding a certain margin to the estimated plant illuminance L ′ is set as an illuminance threshold.

According to such step S ″ -3, it can be said that the illuminance threshold value T2 for the power converter output value M is optimized according to the long-term change in the plant illuminance L after the installation of the photovoltaic power plant P.
Further, the illuminance threshold T2 when the monitoring program (moving average program) S ″ of the third embodiment is executed can be changed while the determination unit 3 determines whether the photovoltaic power plant P is abnormal. In the environment where the photovoltaic power plant P is placed (the direction in which the illuminance sensor 2 is mounted (which is the vertical direction such as the horizontal direction, the vertical direction, or the diagonal direction, the direction, etc.) The illuminance threshold value T2 can be optimized according to the south-middle altitude.
Further, the monitoring program (moving average program) S ″ of the third embodiment is compared with the monitoring program (correlation coefficient / regression line program) S ′ of the second embodiment to calculate the process of obtaining the illuminance threshold T2. The load is low, and the performance of the determination unit 3 (CPU), the storage device, or the storage unit may not be so high.
The other steps in the monitoring program (moving average program) S ″ of the third embodiment are steps S-2, S-4 to S-6 in the monitoring program (illuminance threshold value fixing program) S of the first embodiment. The same as S-21 to S-23 and S-31.

<Other Determination Methods of Illuminance Threshold T2>
In addition, as long as it can be changed while the determination unit 3 determines whether the solar power plant P is abnormal, the illuminance threshold T2 may be determined by any method. For example, the user U The configuration may be changed to a predetermined illuminance threshold T2 via the communication unit 13.

<Solar power plant P under other conditions>
The solar power generation plant P described so far may be placed under various conditions (conditions) such as a snowy day in addition to a sunny day, a cloudy day, a rainy day, and a typhoon day.
In FIG. 19, the power conditioner output value M of the solar power plant P (the solar power plant P is normal) in the mountainous area of Hiroshima Prefecture from December 28, 2014 to January 5, 2015, A change in the plant illuminance L or the like is shown, and one peak of change in the power conditioner output value M or the like is one day.

Of the 9 days, between January 1, 2015 and January 4, 2015, there was snow and no power was generated (the amount of power generated during snowfall is almost the same as at night). Power generation has been resumed from May 5.
Here, between January 1, 2015 and January 4, 2015, the plant illuminance L from the illuminance sensor 2 jumps from about 1.5 times to about 2.0 times from the normal time.
Therefore, another illuminance threshold (high illuminance threshold T2 ′) is added, and in the case of plant illuminance L equal to or higher than the high illuminance threshold T2 ′, it is assumed that there is snow, and the photovoltaic power plant P (power conditioner C). The false alarm judgment may be prevented by temporarily suspending the monitoring.

<Modification of the determination unit 3>
That is, the determination unit 3 determines that the plant illuminance L is greater than the illuminance threshold T2 and higher than the high illuminance threshold T2 ′ while the plant illuminance L is greater than or equal to the illuminance threshold T2 while the power control output value M is equal to or less than the output threshold T1. Then, the error count E may not be counted.
Thereby, when snow is accumulated due to snowfall, even in a normal (non-abnormal) solar power plant P, the plant illuminance L is reduced even though the current value from the power conditioner C is equal to or less than the output threshold value T1. It may happen that the illuminance threshold T2 or higher.
This is because sunlight is reflected by the accumulated snow and becomes brighter (the plant illuminance L becomes higher). Here, a high illuminance threshold T2 ′ larger than the illuminance threshold T2 is provided, and the high illuminance threshold T2 ′ or higher is provided. If the number of errors E is not counted when the plant illuminance L is reached, it can be distinguished whether the illuminance increase due to snow accumulation or an abnormality of the photovoltaic power plant P, and false alarms are suppressed.
In addition to this, it is possible to improve the false alarm suppression even when the solar power plant P is placed in a place where the sunlight can be reflected on the water surface, such as the seaside, lakeside, riverside, etc., except during snowfall.

<Modification of Step S-3 in Monitoring Program S>
In the monitoring system 1 (determination unit 3), the plant illuminance L measured in step S-1 (or the plant illuminance L in the photovoltaic power plant P in step S-3 is measured by the illuminance sensor 2). ) Is equal to or greater than the illuminance threshold T2 and smaller than the high illuminance threshold T2 ′, the process proceeds to Step S-4 described below.
Conversely, if the plant illuminance L is equal to or greater than the illuminance threshold T2 and equal to or greater than the high illuminance threshold T2 ′, or is smaller than the illuminance threshold T2, the process proceeds to step S-31 described later (step S-3).
In step S′-3 and S ″ -3 as well, a high illuminance threshold T2 ′ may be provided similarly.

<Others>
The present invention is not limited to the embodiment described above. Each structure of the monitoring system 1 or the photovoltaic power plant P, or the overall structure, shape, dimensions, and the like can be appropriately changed in accordance with the spirit of the present invention.
In addition to the illuminance sensor 2, the monitoring system 1 refers to only a measurement area having a high correlation with the power converter output value M in a temperature sensor or the like, and determines whether there is an abnormality in the photovoltaic power plant P (power conditioner C). May be.

  The monitoring system according to the present invention may be retrofitted to the solar power plant, or may be attached to the solar power plant from the beginning, and the place where the solar power plant according to the present invention is installed, There is no particular limitation, and for example, it may be a building, its rooftop, a mountainous area, a residential land, a forest, a wilderness, a hybrid land, a rice field, a field, a snowfall, a seaside, a riverside, etc., and the present invention is installed in any region. It can also be used for solar power plants.

DESCRIPTION OF SYMBOLS 1 Monitoring system 2 Illuminance sensor 3 Judgment part D Solar cell C Power conditioner P Photovoltaic power plant M Power conditioner output value T1 Output threshold L Plant illumination T2 Illuminance threshold T2 'High illumination threshold E Error frequency T3 Error threshold number

Claims (4)

A monitoring system for determining the presence or absence of an abnormality in a photovoltaic power plant having a power conditioner that converts current from a solar cell from direct current to alternating current,
An illuminance sensor for measuring plant illuminance in the solar power plant;
While the power converter output value including at least one value among the current, voltage, and power from the power conditioner is equal to or less than the output threshold, the number of errors when the plant illuminance is equal to or greater than the illuminance threshold is counted. A determination unit that determines that there is an abnormality in the photovoltaic power plant if is equal to or greater than an error threshold;
A monitoring system characterized by comprising:   The monitoring system according to claim 1, wherein the illuminance threshold is a threshold that can be changed while the determination unit determines whether there is an abnormality in the photovoltaic power plant.   While the power control output value is equal to or lower than the output threshold value, the determination unit determines that the error occurs if the plant illuminance is equal to or greater than the high illuminance threshold value that is greater than the illuminance threshold value. The monitoring system according to claim 1 or 2, wherein the monitoring system does not count the number of times. The monitoring system according to any one of claims 1 to 3,
A solar power plant, comprising: a communication unit that communicates a determination result of the presence or absence of abnormality of the monitoring system with respect to the solar power plant to the outside of the monitoring system.