JP4353115B2 - Isolated operation detection device, isolated operation detection method, and grid interconnection system - Google Patents

Description

  The present invention is disposed between a distributed power source such as a solar power generator, a gas engine, a wind power generator, a hydroelectric power generator, and the like and a system power source (commercial power source), and the distributed power source alone when the power supply of the system power source is stopped. The present invention relates to an isolated operation detection device, an isolated operation detection method, and a grid interconnection system for detecting operation.

  In recent years, when a distributed power source such as a solar power generator and a system power source are interconnected via an inverter with a reverse power flow, when the distributed power source alone cannot supply power, the power is supplied from the system power source side. A grid interconnection system has been developed.

  This type of grid-connected system needs to prevent reverse charging from the distributed power source to the grid power source when the grid power supply is stopped. An isolated operation detection device that detects the isolated operation of the power supply and disconnects it from the system power supply side and stops the drive of the inverter is adopted.

  In addition, as a method of detecting the isolated operation of the distributed power supply, the isolated operation of the distributed power supply is detected by detecting changes in the voltage waveform, phase, etc. when the operation is switched from the interconnected operation to the system power supply. An active disturbance signal such as reactive power fluctuation, active power fluctuation, frequency shift or harmonic injection is added between the passive power supply and the system power supply and the distributed power supply, and the grid connection between the system power supply and the distributed power supply An active method is known in which a disturbance signal included in a system voltage at a point is detected, and isolated operation of the distributed power source is detected based on the detection result.

  However, in general, the passive method can detect isolated operation without affecting the system power supply side, but the dead zone is wide, so the dead zone is narrower than the passive method. The fact is that the weaknesses are compensated by the combined use with the traditional method.

  In recent years, in such an active system, in order to construct a system capable of supplying a large amount of generated power, a plurality of distributed power sources are connected in parallel to a system power source and operated in parallel. In this case, since the disturbance signals for detecting the isolated operation of each distributed power supply interfere with each other and cancel each other, the detection sensitivity is slowed down and the isolated operation of the distributed power supply can be detected. There is a situation that cannot be done.

  Therefore, in order to cope with such a situation, even when parallel operation is performed in which a plurality of distributed power sources are connected in parallel to the system power source, the single operation of the distributed power source is stopped when the power supply of the system power source is stopped. There is known a system that can detect (see, for example, Patent Document 1).

  According to this patent document 1, even when a plurality of distributed power sources are operating in parallel, the system detects a single operation of the distributed power source when the power supply of the system power source is stopped. Since the phase of minute periodic fluctuations of reactive power supplied by each inverter on multiple distributed power sources is synchronized and the frequency fluctuation at the grid connection point is monitored, the single operation state is detected. Interference such as power transfer between the inverters of the base is prevented, so that the independent operation of the distributed power source can be reliably detected.

  However, according to Patent Document 1, the phase of the periodic minute fluctuations of the reactive power is synchronized with the time information from the artificial satellite, the frequency fluctuation at the grid connection point is monitored, and the isolated operation state is determined based on the monitoring result. Although it is theoretically disclosed that detection is performed, since a system signal synchronized with the phase of the system voltage between the system power supply and the distributed power supply is not used, an inverter of a plurality of distributed power supplies with respect to the system power supply The disturbance signal cannot be applied at the timing synchronized with the signal, and multiple disturbance signals will interfere with each other. As a result, the detection sensitivity will slow down and the single operation of the distributed power supply will actually be detected. I think you can't do it.

  Therefore, the present applicant has disclosed a system that can detect the independent operation of the distributed power source when the power supply of the system power source is stopped even during the parallel operation of the system power source and the plurality of distributed power sources ( For example, see Patent Document 2). FIG. 4 is an explanatory diagram briefly showing signal waveforms used in the isolated operation detection process of Patent Document 2.

  This Patent Document 2 discloses an active method for changing the output of a power conditioner (hereinafter simply referred to as a power conditioner) between a system power source and a distributed power source even during parallel operation of the system power source and a plurality of distributed power sources. Thus, in the system for detecting the independent operation of the distributed power supply when the power supply of the system power supply is stopped, a plurality of power conditioners are connected to each other by a synchronization signal line. Each power conditioner has a built-in single operation detection function for detecting single operation of the distributed power source.

  Each power conditioner generates a system signal (FIG. 4 (B)) synchronized with the phase of the system voltage (see FIG. 4 (A)) between the distributed power supply and the system power supply. Further, among the plurality of power conditioners, a preset master power conditioner generates a synchronization signal shown in FIG. 4C including a phase advance signal and a phase delay signal based on the system signal, and synchronizes the generated synchronization signal. It is distributed to other power conditioners via signal lines.

  Then, the base unit power conditioner changes the power condition output shown in FIG. 4E to the advance side (plus side) or the delay side (minus side) based on the synchronization signal shown in FIG. 4C (FIG. 4). (See (D)) is applied to the system voltage in a state where the power conditioners are synchronized with each other.

  The other power conditioner receives the synchronization signal generated by the master unit power conditioner via the synchronization signal line, and applies a disturbance signal to the system voltage in a state where the power conditioners are synchronized with each other based on the synchronization signal. is there.

Therefore, according to Patent Document 2, a plurality of power conditioners are connected to each other through a synchronization signal line, and among the plurality of power conditioners, a synchronization signal generated by the master unit power conditioner is distributed to another power conditioner via the synchronization signal line. Thus, even during the parallel operation of the system power supply and the plurality of distributed power supplies, each power conditioner applies a disturbance signal to the system voltage in a synchronized state based on the synchronization signal. The fluctuations in the disturbance signal applied to each other do not interfere with each other, and the single operation of the distributed power supply can be detected even during the parallel operation of the plurality of distributed power supplies.
Japanese Patent Laid-Open No. 9-74684 (see abstract and FIG. 1) Japanese Patent No. 3028205 (see abstract and FIG. 1)

  However, according to the above-mentioned conventional patent document 2, a plurality of power conditioners (independent operation detection devices) are interconnected to a synchronization signal line, and a synchronization signal is generated by a master unit power conditioner among the plurality of power conditioners. Is distributed to other power conditioners via the synchronization signal line, and a disturbance signal is applied to the system voltage in a state where the power conditioners are mutually synchronized. Since it is arranged, it is necessary to lay a synchronization signal line for distributing the synchronization signal between the power conditioners in the household, and the laying work may be very difficult.

  Further, according to the above-described conventional Patent Document 2, the synchronization signal generated by the master unit power conditioner is distributed to another power conditioner via the synchronization signal line. However, when the synchronization signal line is disconnected, Since synchronization cannot be established with each other, fluctuations in disturbance signals applied to the system voltage interfere with each other, and as a result, it may be impossible to detect isolated operation of the distributed power source.

  Further, according to the above-mentioned conventional Patent Document 2, when there is a distributed power source connected in reverse phase among a plurality of distributed power sources linked to the system power source, FIG. 4 (A), (B) As shown in FIGS. 4F and 4G, the system signals are always synchronized in the opposite phase between the power conditioners as shown in FIGS. 4C and 4H while having a phase difference of 180 degrees. Therefore, as shown in FIGS. 4D and 4E and FIGS. 4I and 4J, the disturbance signals cancel each other, and the isolated operation cannot be detected. Is also possible.

  The present invention has been made in view of the above points, and the object of the present invention is to eliminate the need for a synchronization signal line and prevent mutual interference by applying a disturbance signal in synchronism between isolated operation detection devices. As a result, it is an object to provide an isolated operation detection device, an isolated operation detection method, and a grid interconnection system that can detect an isolated operation.

  In addition, the present invention has been made in view of the above points, and an object of the present invention is to detect an isolated operation even when a plurality of distributed power sources are connected in opposite phases to a system power source. An object of the present invention is to provide an isolated operation detection device capable of

In order to achieve the above object, an isolated operation detection device of the present invention is disposed between a distributed power supply and a system power supply, and detects an isolated operation of the distributed power supply when the power supply of the system power supply is stopped. A system signal generating means for detecting a system voltage between the distributed power source and the system power source and generating a system signal synchronized with a predetermined phase of the system voltage, and an external synchronization signal source other than the islanding detection device receiving an external synchronization signal from the basis of the external synchronizing signal receiving means, the external sync signal received by system signal generated by the system signal generating means and said external synchronizing signal receiving means, phase advance signal and the delayed phase signal an internal sync signal generating means for generating an internal synchronization signal including in a predetermined pattern, the system voltage disturbance signal based on an internal synchronization signal generated by the internal synchronization signal generating means Disturbance signal applying means to be applied, and a disturbance signal included in the system voltage at the grid connection point between the distributed power supply and the system power supply are detected, and the independent operation of the distributed power supply is determined based on the detection result An independent operation determination unit, and when the internal synchronization signal generation unit receives a high-level system signal among the system signals synchronized with a predetermined phase of the system voltage at the detection timing of the external synchronization signal, An internal synchronization signal starting from a phase advance signal is generated in response to a level system signal, and a low level system signal is received from system signals synchronized with a predetermined phase of the system voltage at the detection timing of the external synchronization signal. At the timing when the next high level system signal is received, the internal synchronization signal starting from the phase advance signal corresponding to the high level system signal is generated. Was so that has been.

  In the isolated operation detection device of the present invention, the external synchronization signal receiving means includes time information of an incoming radio clock signal, time signal of an incoming AM broadcast, time signal of an incoming FM broadcast, time information of an incoming GPS signal, Any one of time information of an incoming TV signal, a time signal via a telephone line, a regular signal via the Internet, and a synchronization signal for power line communication is received as the external synchronization signal.

In order to achieve the above object, an isolated operation detection method of the present invention is arranged between a distributed power supply and a system power supply and detects an isolated operation of the distributed power supply when the power supply of the system power supply is stopped. Detecting a system voltage between the distributed power source and the system power source, generating a system signal synchronized with a predetermined phase of the system voltage, and an external source from an external synchronization signal source other than the islanding detection device A step of receiving a synchronization signal; a step of generating an internal synchronization signal including a phase advance signal and a phase delay signal in a predetermined pattern based on the system signal and the external synchronization signal; and a disturbance based on the internal synchronization signal Applying a signal to the system voltage, detecting a disturbance signal included in the system voltage at a system interconnection point between the distributed power source and the system power source, and based on the detection result , Have a determining islanding of the dispersed type power supply, the internal synchronizing signal, the line signal of the high level of the synchronous system signal to a predetermined phase of the system voltage at the detection timing of the external synchronization signal When received, it is an internal synchronization signal starting from a phase advance signal generated corresponding to the system signal at the same high level, and a low level of the system signal synchronized with a predetermined phase of the system voltage at the detection timing of the external synchronization signal. When a low-level system signal is received among the level system signals, the internal synchronization signal starts with a phase advance signal generated corresponding to the high-level system signal at the timing when the next high-level system signal is received. And so on.

  In the isolated operation detection method of the present invention, the external synchronization signal includes time information of an incoming radio clock signal, an incoming AM broadcast time signal, an incoming FM broadcast time signal, an incoming GPS signal, an incoming television signal, It is one of a time signal via a telephone line, a regular signal via the Internet, and a synchronization signal for power line communication.

In order to achieve the above object, the grid interconnection system of the present invention includes a plurality of distributed power sources that are interconnected to the grid power source, and the distributed power source is disposed for each of the distributed power sources, and when the power supply of the grid power source is stopped A system interconnection system having a plurality of islanding operation detection devices for detecting islanding operation of a power supply, and operating the plurality of distributed power sources in parallel with the system power supply, wherein each islanding operation detection device detects the system voltage between the dispersed type power supply and system power supply, receives the system signal generating means for generating a line signal in synchronization with the predetermined phase of the system voltage, the external sync signal from external synchronizing signal source Based on the external synchronization signal receiving means, the system signal generated by the system signal generating means and the external synchronization signal received by the external synchronization signal receiving means, the phase advance signal and the phase delay signal are included in a predetermined pattern. Internal synchronization signal An internal synchronization signal generating means for generating a disturbance signal applying means for applying a disturbance signal to the system voltage based on the internal synchronization signal generated by the internal synchronization signal generating means, and a system between the distributed power source and the system power source. detecting a disturbance signal included in the system voltage at connecting point, on the basis of the detection result, possess a single operation determining means for determining the isolated operation of the dispersed type power supply, said internal synchronization signal generating means, said When a high-level system signal is received among the system signals synchronized with the predetermined phase of the system voltage at the detection timing of the external synchronization signal, an internal synchronization signal starting from a phase advance signal is generated corresponding to the high-level system signal And receiving a low level system signal among the system signals synchronized with a predetermined phase of the system voltage at the detection timing of the external synchronization signal, the next high level system At the timing of receiving the signal, and so, is configured to generate an internal synchronization signal starting from the phase advance signal corresponding to the system signals having the same high level.

  In the grid interconnection system of the present invention, the external synchronization signal receiving means includes time information of an incoming radio clock signal, incoming time signal of AM broadcast, incoming time signal of FM broadcast, incoming GPS signal, incoming television Any one of a signal, a time signal via a telephone line, a regular signal via the Internet, and a synchronization signal for power line communication is received as the external synchronization signal.

  According to the isolated operation detection device of the present invention configured as described above, it has external synchronization signal receiving means for receiving a common external synchronization signal from an external synchronization signal source other than the isolated operation detection device, and a system signal And generating an internal synchronization signal based on the external synchronization signal, applying a disturbance signal to the system voltage based on the internal synchronization signal, and generating a disturbance signal included in the system voltage at the system interconnection point between the distributed power source and the system power source. Since the detection and the single operation of the distributed power source are detected based on the detection result, even if a plurality of distributed power sources are operated in parallel with respect to the system power source, It is not necessary to lay a synchronization signal line to interconnect each other, and it is possible to reliably prevent mutual interference of disturbance signals by synchronizing the independent operation detection devices using a common external synchronization signal. It is possible to detect the rotation.

  According to the isolated operation detection device of the present invention, for example, time information of a radio clock signal, time signal of AM broadcast, time signal of FM broadcast, time information of GPS signal, time information of TV signal, time signal via a telephone line, Since any one of the scheduled signal via the Internet and the synchronization signal for power line communication is received as the external synchronization signal, the external signal can be obtained without using the synchronization signal line for interconnecting the independent operation detection devices. Since the common external synchronization signal can be obtained from the single operation detection devices, the mutual interference of the disturbance signals can be reliably prevented by synchronizing the single operation detection devices, and as a result, the single operation can be detected.

  According to the isolated operation detection device of the present invention, when a system signal is received at the detection timing of the external synchronization signal, an internal synchronization signal having a predetermined pattern including a phase advance signal and a phase delay signal corresponding to the system signal is generated. Since it did in this way, the independent operation detection apparatus can apply the disturbance signal based on the internal synchronization signal of a predetermined pattern to the system voltage at the detection timing of the common external synchronization signal.

  According to the isolated operation detection device of the present invention, when a high-level system signal is received at the detection timing of the external synchronization signal, an internal synchronization signal having a predetermined pattern corresponding to the high-level system signal is generated, and the external When a low-level system signal is received at the detection timing of the synchronization signal, it waits until the next high-level system signal is received, and when the next high-level system signal is received, it corresponds to the next high-level system signal. Since the internal synchronization signal of a predetermined pattern is generated, for example, when the system is 50 Hz, the fluctuation period of the system signal is 10 msec interval, and the fluctuation period of the phase advance signal and the delay signal of the internal synchronization signal is 100 msec interval. In this case, even if multiple distributed power sources are connected in reverse phase to the system power source, the generation of disturbance signals is delayed by 10 milliseconds, but Can disturbance signal applied at apparatus to eliminate the situation that would be canceled with each other in order not to be applied in opposite phases at all times, as a result, it is possible to detect the islanding state.

  According to the isolated operation detection method of the present invention configured as described above, a common external synchronization signal from an external synchronization signal source other than the isolated operation detection device is received, and internal synchronization is performed based on the system signal and the external synchronization signal. A signal is generated, a disturbance signal is applied to the system voltage based on the internal synchronization signal, a disturbance signal included in the system voltage at the system interconnection point between the distributed power source and the system power source is detected, and based on the detection result Since a single operation of a distributed power source is detected, even if a plurality of distributed power sources are operated in parallel with a system power source, a synchronization signal line for interconnecting conventional single operation detectors is provided. There is no need to lay down, and the isolated operation detection devices synchronize with each other using a common external synchronization signal, so that mutual interference of disturbance signals can be reliably prevented, and as a result, isolated operation can be detected.

  According to the isolated operation detection method of the present invention, for example, time information of a radio clock signal, time signal of AM broadcast, time signal of FM broadcast, time information of GPS signal, time information of TV signal, time signal via a telephone line, Since any one of the scheduled signal via the Internet and the synchronization signal for power line communication is received as the external synchronization signal, the external signal can be obtained without using the synchronization signal line for interconnecting the independent operation detection devices. Since the common external synchronization signal can be obtained from the single operation detection devices, the mutual interference of the disturbance signals can be reliably prevented by synchronizing the single operation detection devices, and as a result, the single operation can be detected.

  According to the grid interconnection system of the present invention configured as described above, a common external synchronization signal from an external synchronization signal source other than the isolated operation detection device is received on each isolated operation detection device side, and the system signal and the external An internal synchronization signal is generated based on the synchronization signal, a disturbance signal is applied to the system voltage based on the internal synchronization signal, and a disturbance signal included in the system voltage at the system connection point between the distributed power source and the system power source is detected. Since the single operation of the distributed power source is detected based on the detection result, even if a plurality of distributed power sources are operated in parallel with respect to the system power source, There is no need to lay a synchronization signal line to connect, and the isolated operation detectors synchronize with each other using a common external synchronization signal to reliably prevent mutual interference of disturbance signals. It can be.

  According to the grid interconnection system of the present invention, for example, time information of a radio clock signal, time signal of AM broadcast, time signal of FM broadcast, time information of GPS signal, time information of TV signal, time signal via telephone line, Since any one of the scheduled signal via the Internet and the synchronization signal for power line communication is received as the external synchronization signal, the external signal can be obtained without using the synchronization signal line for interconnecting the independent operation detection devices. Since the common external synchronization signal can be obtained from the single operation detection devices, the mutual interference of the disturbance signals can be reliably prevented by synchronizing the single operation detection devices, and as a result, the single operation can be detected.

  Hereinafter, a grid interconnection system showing an embodiment relating to an isolated operation detection device of the present invention will be described based on the drawings. FIG. 1 is a block diagram showing a schematic configuration inside the grid interconnection system showing the present embodiment.

  A grid interconnection system 1 shown in FIG. 1 includes a grid power source 2, a plurality of distributed power sources 3 (3A, 3B) such as solar power generators, and a DC power generated by the distributed power source 3 as an AC power. Power converter 4 (4A, 4B) for converting to power supply, and general load 5 (5A, 5B) such as household electrical equipment for supplying AC power converted by power converter 4 or AC power from system power supply 2 Yes.

  Further, between the distributed power source 3 and the system power source 2, an independent operation detection device 10 (10 </ b> A, 10 </ b> B) that detects an isolated operation of the distributed power source 3 when the power supply of the system power source 2 is stopped is arranged. In addition, the independent operation detection apparatus 10 shall be arrange | positioned for every power conditioner 4 of the distributed power supply 3. FIG.

  In order to stop the independent operation of the distributed power source 3, each of the individual operation detection devices 10 has a cutoff switch 11 that cuts off the connection between the power conditioner 4 and the system power supply 2, and a system voltage between the power conditioner 4 and the system power supply 2. For example, a disturbance signal generation unit 12 that applies a disturbance signal of reactive power fluctuation, a system monitoring unit 13 that detects a system voltage at the system interconnection point X, and a disturbance signal included in the system voltage detected by the system monitoring unit 13 Based on the detection result of the disturbance signal, the isolated operation determination unit 14 that determines the isolated operation of the distributed power source 3 when the power supply of the system power supply 2 is stopped, and the determination result of the isolated operation determination unit 14 The synchronization protection circuit 15 for driving and controlling the cutoff switch 11, the external synchronization signal receiving unit 16 for receiving the incoming common external synchronization signal, and the internal synchronization signal based on the external synchronization signal and the system signal Based on the internal synchronization signal generated by the internal synchronization signal generation unit 17, the disturbance signal generation unit 12 applies a disturbance signal at a predetermined timing to the system voltage based on the internal synchronization signal generation unit 17 to be generated. Have.

  When the system monitoring unit 13 detects the system voltage at the system connection point X, the system monitoring unit 13 transmits the system voltage to the isolated operation determination unit 14 and internally generates a pulsed system signal synchronized with the 90-degree phase of the system system voltage. The signal is transmitted to the synchronization signal generator 17. The fluctuation cycle of the system signal is 10 msec at 50 Hz.

  The external synchronization signal receiving unit 16 receives an AM radio broadcast time signal as an external synchronization signal from a common distribution source 20 such as an AM radio broadcast station.

  The internal synchronization signal generation unit 17 generates an internal synchronization signal including a phase advance signal and a phase delay signal based on the external synchronization signal and the system signal. The internal synchronization signal corresponds to a pattern that is repeatedly output at a fluctuation period of 100 msec in the order of, for example, a phase advance signal, a phase delay signal, a phase advance signal, a phase delay signal,.

  The control unit 18 controls the disturbance signal generation unit 12 to apply a disturbance signal at a predetermined timing to the system voltage between the power conditioner 4 and the system power supply 2 based on the internal synchronization signal. That is, when the control unit 18 detects the internal synchronization signal of the phase advance signal, the control unit 18 controls the disturbance signal generation unit 12 to apply the phase advance disturbance signal to the system voltage and also detects the internal synchronization signal of the phase delay signal. Then, the disturbance signal generator 12 is controlled to apply a late-phase disturbance signal to the system voltage.

  When the system monitoring unit 13 detects the system voltage at the system connection point X, the islanding operation determination unit 14 detects a disturbance signal included in the detected system voltage, and based on the detection result, the isolated operation power source 3 This is to determine the isolated operation.

  When the isolated operation determination unit 14 determines that the distributed power supply 3 is operating independently, the interconnection protection circuit 15 drives and controls the disconnection switch 11 to disconnect the connection between the power conditioner 4 and the system power supply 2. At the same time, if the isolated operation determination unit 14 determines that the distributed power supply 3 is not operated independently, the cutoff switch 11 is driven and controlled to maintain the connection between the power conditioner 4 and the system power supply 2.

  The system signal generating means described in the claims is the system monitoring section 13, the external synchronization signal source is the common signal source 20, the external synchronization signal receiving means is the external synchronization signal receiving section 16, and the internal synchronization signal generating means is the internal synchronization signal generating section. 17, the disturbance signal applying unit corresponds to the disturbance signal generating unit 12 and the control unit 18, and the isolated operation determining unit corresponds to the isolated operation determining unit 14.

  Next, the operation of the isolated operation detection device 10 which is a main part of the grid interconnection system 1 showing the present embodiment will be described. FIG. 2 is an explanatory diagram showing signal waveforms used in the isolated operation detection process of the isolated operation detection device 10.

  The system monitoring unit 13 in the isolated operation detection device 10 detects the system voltage between the power conditioner 4 and the system power supply 2 as shown in FIG. The system monitoring unit 13 generates, for example, a pulsed system signal shown in FIG. 2B that is synchronized with the 90-degree phase of the system voltage and is synchronized with the phase.

  In addition, the external synchronization signal generator 16 receives an external synchronization signal coming from the common signal source 20.

  The internal synchronization signal generator 17 includes a phase advance signal and a phase delay signal as shown in FIG. 2D based on the system signal shown in FIG. 2B and the external synchronization signal shown in FIG. Generate an internal synchronization signal.

  Based on the internal synchronization signal shown in FIG. 2 (D), the control unit 18 generates a disturbance signal so as to apply a disturbance signal at a predetermined timing shown in FIG. 2 (E) to the system voltage between the power conditioner 4 and the system power supply 2. The unit 12 is controlled. That is, when the control unit 18 detects the internal synchronization signal of the phase advance signal, the control unit 18 controls the disturbance signal generation unit 12 to apply the phase advance disturbance signal to the system voltage and also detects the internal synchronization signal of the phase delay signal. Then, the disturbance signal generator 12 is controlled to apply a late-phase disturbance signal to the system voltage.

  Similarly, the other isolated operation detection device 10 (10B) generates a system signal based on the 90-degree phase of the system voltage between the power conditioner 4 and the system power supply 2 and receives a common external synchronization signal. Then, an internal synchronization signal is generated based on the system signal and the external synchronization signal, and a disturbance signal is applied to the system voltage between the power conditioner 4 and the system power supply 2 based on the internal synchronization signal.

  Further, for example, when the distributed power supply 3A is connected to the system power supply 2 in the positive phase and the distributed power supply 3B is connected to the system power supply 2 in the reverse phase, and these distributed power supplies 3 are operated in parallel, The independent operation detection process of the operation detection device 10A and the independent operation detection device 10B will be described. FIG. 3 is an explanatory diagram briefly showing signal waveforms of the isolated operation detection device 10A and the isolated operation detection device 10B.

  When the isolated operation detection device 10A generates a system signal (see FIG. 3B) synchronized with the 90-degree phase of the positive-phase system voltage shown in FIG. 3A, and receives the external synchronization signal, Based on the external synchronization signal, an internal synchronization signal including a phase advance signal and a phase delay signal shown in FIG. 3D is generated, and a disturbance signal is applied to the system voltage based on the internal synchronization signal.

  That is, when the internal synchronization signal generation unit 17 of the isolated operation detection device 10A receives a high-level system signal at the detection timing of the external synchronization signal, the internal synchronization signal starting from the phase advance signal corresponding to the high-level system signal Is generated. When the control unit 18 of the isolated operation detection device 10A detects the internal synchronization signal, the control unit 18 starts applying the phase disturbance signal to the system voltage.

  On the other hand, when the system monitoring unit 13 of the isolated operation detection device 10B generates a system signal (see FIG. 3 (H)) synchronized with the 90-degree phase of the system voltage of the opposite phase shown in FIG. It becomes an inversion state with the system signal shown in 3 (B).

  When the isolated operation detection device 10B receives the external synchronization signal, it generates the internal synchronization signal shown in FIG. 3 (J) based on the system signal shown in FIG. 3 (H) and the external synchronization signal shown in FIG. 3 (I). Based on this internal synchronization signal, a disturbance signal is applied to the system voltage as shown in FIG. That is, when the internal synchronization signal generation unit 17 receives a low-level system signal at the detection timing of the external synchronization signal, the internal synchronization signal generation unit 17 waits for 10 milliseconds until the next high-level system signal is received, and receives the next high-level system signal. At the received timing, an internal synchronization signal corresponding to the high-level system signal is generated starting from the phase advance signal. When the control unit 18 of the isolated operation detection device 10B detects the internal synchronization signal, the control unit 18 starts applying the phase disturbance signal to the system voltage with a delay of 10 milliseconds from the isolated operation detection device 10A.

  In other words, the isolated operation detection device 10A on the distributed power supply 3A side connected in the positive phase and the isolated operation detection device 10B on the distributed power supply 3B side connected in the reverse phase generate a disturbance signal based on the external synchronization signal. Therefore, the disturbance signal is not always output in the reverse phase as in the prior art, and the disturbance signals interfere with each other only by delaying the start of application of the disturbance signal by 10 msec. It is possible to prevent situations that cancel each other, and as a result, even if there is a distributed power supply 3 connected in reverse phase among the distributed power supplies 3 in parallel operation, it is possible to detect an isolated operation. it can.

  According to the present embodiment, the external synchronization signal receiving unit 16 that receives the external synchronization signal from the common signal source 20 other than the islanding detection device 10 is provided, and the internal synchronization signal is obtained based on the system signal and the external synchronization signal. Generate and apply a disturbance signal to the system voltage based on the internal synchronization signal, detect the disturbance signal included in the system voltage at the system interconnection point X between the power conditioner 4 and the system power supply 2, and distribute based on the detection result Since the single operation of the power source 3 is detected, even if a plurality of distributed power sources 3 are operated in parallel with the system power source 2, the synchronization signal for interconnecting the single operation detection devices 10 as in the prior art There is no need to lay a line, and the isolated operation detection devices 10 are synchronized with each other, so that mutual interference of disturbance signals can be reliably prevented, and as a result, isolated operation can be detected.

  According to the present embodiment, the AM radio broadcast time signal is received as a common external synchronization signal. Therefore, even if the synchronization signal line for interconnecting the independent operation detection devices 10 is not used, the signal is externally supplied. Since a common external synchronization signal can be acquired, the isolated operation detection devices 10 are synchronized with each other, so that mutual interference of disturbance signals can be reliably prevented, and as a result, isolated operation can be detected.

  According to the present embodiment, when the system signal is received at the detection timing of the external synchronization signal, the internal synchronization signal having a predetermined pattern including the advanced phase signal and the delayed phase signal corresponding to the system signal is generated. In addition, it is possible to apply a disturbance signal based on the internal synchronization signal of a predetermined pattern to the system voltage at the detection timing of the external synchronization signal common to the isolated operation detection devices 10.

  According to this embodiment, when a high-level system signal is received at the detection timing of the external synchronization signal, an internal synchronization signal having a predetermined pattern corresponding to the high-level system signal is generated, and the detection timing of the external synchronization signal When a low-level system signal is received, the system waits until the next high-level system signal is received. When the next high-level system signal is received, internal synchronization of a predetermined pattern corresponding to the next high-level system signal is received. Since the signal is generated, for example, when the fluctuation period of the system signal is 10 msec and the fluctuation period of the phase advance signal and the delay signal of the internal synchronization signal is 100 msec, a plurality of dispersions are performed with respect to the system power supply. Even if the power sources 3 are connected in reverse phase with each other, the disturbance signal generated by the isolated operation detection device 10 is always in reverse phase although the generation of the disturbance signal is delayed by 10 milliseconds. It is possible to eliminate the situation that would be canceled with each other in order will not be pressurized, as a result, it is possible to detect the islanding state.

  In the above embodiment, the time signal of the common AM radio broadcast that arrives at the external synchronization signal is used. For example, the time information of the radio clock signal, the time signal of the FM broadcast, the time information of the GPS signal, The same effect can be obtained even with time information, a time signal via a telephone line, a regular signal via the Internet, and a synchronization signal for power line communication.

  In the above embodiment, the external synchronization signal receiving unit 16 has an AM broadcast receiving function for receiving a time signal of AM radio broadcast. For example, FM broadcast reception for receiving a time signal of FM radio broadcast is provided. The external synchronization signal receiving unit 16 has a reception function for receiving each external synchronization signal such as a GPS reception function for receiving functions and GPS signal time information, and a desired reception function can be selected according to a user's setting operation. Needless to say, the same effect can be obtained.

  In the above embodiment, the reactive power fluctuation has been described as an example of the active disturbance signal. However, even if a disturbance signal such as active power fluctuation, frequency shift, and harmonic injection is used, the same applies. Needless to say, the system monitoring unit 13 may detect the system voltage, frequency, phase, harmonics, and the like necessary for detecting an isolated operation.

  Further, in the above embodiment, the isolated operation detection device 10 is added outside the power conditioner 4, but the same effect can be obtained even if the isolated operation detection device 10 is built in the power conditioner 4. Needless to say.

  According to the isolated operation detection device of the present invention, it has an external synchronization signal receiving means for receiving a common external synchronization signal from an external synchronization signal source other than the isolated operation detection device, and is based on the system signal and the external synchronization signal. A synchronization signal is generated, a disturbance signal is applied to the system voltage based on the internal synchronization signal, a disturbance signal included in the system voltage at the system connection point between the distributed power source and the system power source is detected, and the detection result Since the independent operation of the distributed power source is detected based on the synchronization signal line for interconnecting the independent operation detection devices as in the past even if a plurality of distributed power sources are operated in parallel with the system power source. It is possible to detect the isolated operation as a result by reliably preventing mutual interference of the disturbance signals by synchronizing the isolated operation detectors using a common external synchronization signal. Because, it is useful for system interconnection system or the like for executing a plurality of distributed operation for connecting interconnection to the system power supply.

It is a block diagram which shows schematic structure inside the grid connection system which shows embodiment in connection with the isolated operation detection apparatus of this invention. It is explanatory drawing which shows the signal waveform used for the isolated operation detection process of the isolated operation detection apparatus in connection with this Embodiment. It is explanatory drawing which shows simply the relationship of the use waveform figure of the independent operation detection apparatus connected to the system power supply in connection with this Embodiment in the positive phase, and the independent operation detection apparatus connected in the reverse phase. It is explanatory drawing which shows simply the relationship of the use waveform figure of the independent operation detection apparatus connected to the system power supply of the prior art in the normal phase, and the independent operation detection apparatus connected in the reverse phase.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 System interconnection system 2 System power supply 3 Distributed type power supply 10 Independent operation detection apparatus 12 Disturbance signal generation part (disturbance signal application means)
13 System monitoring unit (system signal generating means)
14 Independent operation determination unit (independent operation determination means)
16 External synchronization signal receiver (external synchronization signal receiver)
17 Internal sync signal generator (internal sync signal generator)
18 Control unit (disturbance signal applying means)
20 Common signal source (external synchronization signal source)

Claims (6)

An isolated operation detection device that is disposed between a distributed power supply and a system power supply and detects an isolated operation of the distributed power supply when the power supply of the system power supply is stopped,
A system signal generating means for detecting a system voltage between the distributed power source and the system power source and generating a system signal synchronized with a predetermined phase of the system voltage;
An external synchronization signal receiving means for receiving an external synchronization signal from an external synchronization signal source other than the isolated operation detection device;
Based on the system signal generated by the system signal generating means and the external synchronization signal received by the external synchronization signal receiving means , an internal synchronization signal that includes an advanced phase signal and a delayed phase signal in a predetermined pattern is generated. Synchronization signal generating means;
Disturbance signal applying means for applying a disturbance signal to the system voltage based on the internal synchronization signal generated by the internal synchronization signal generating means,
Detecting a disturbance signal included in the system voltage by the grid interconnection point between the dispersed type power supply and system power supply, based on the detection result, and a single operation determining means for determining the isolated operation of the dispersed type power supply And
The internal synchronization signal generating means;
When a high-level system signal is received from the system signals synchronized with a predetermined phase of the system voltage at the detection timing of the external synchronization signal, an internal synchronization signal starting from a phase advance signal is generated corresponding to the high-level system signal As well as
When a low-level system signal is received among the system signals synchronized with a predetermined phase of the system voltage at the detection timing of the external synchronization signal, the system signal becomes the high-level system signal at the timing when the next high-level system signal is received. Configured to generate an internal synchronization signal starting from the corresponding phase advance signal,
An isolated operation detection device. The external synchronization signal receiving means includes time information of an incoming radio clock signal, time signal of an incoming AM broadcast, time signal of an incoming FM broadcast, time information of an incoming GPS signal, time information of an incoming television signal, telephone time signal via line, independent operation detecting apparatus of the punctual signal, and according to claim 1, wherein any one of the synchronizing signals of the power line communications, characterized in that received as the external synchronizing signal via the Internet. A single operation detection method for detecting a single operation of the distributed power source, which is disposed between a distributed power source and a system power source, and stops power supply of the system power source,
Detecting a system voltage between the distributed power source and the system power source, and generating a system signal synchronized with a predetermined phase of the system voltage;
Receiving an external synchronization signal from an external synchronization signal source other than the islanding detection device;
Based on the system signal and the external synchronization signal, generating an internal synchronization signal including a phase advance signal and a phase delay signal in a predetermined pattern ;
Applying a disturbance signal to the system voltage based on the internal synchronization signal;
Wherein detecting a disturbance signal included in the system voltage by the grid interconnection point between the dispersed type power supply and system power supply, based on the detection result, possess and determining the independent operation of the dispersed type power supply,
The internal synchronization signal is
When a high-level system signal is received from the system signals synchronized with a predetermined phase of the system voltage at the detection timing of the external synchronization signal, internal synchronization starts from a phase advance signal generated corresponding to the high-level system signal A signal,
When receiving a low-level system signal among the low-level system signals among the system signals synchronized with the predetermined phase of the system voltage at the detection timing of the external synchronization signal, at the timing of receiving the next high-level system signal, It is an internal synchronization signal that starts with a phase advance signal generated corresponding to the high level system signal,
An isolated operation detection method characterized by the above. The external synchronization signal includes time information of an incoming radio clock signal, time signal of an incoming AM broadcast, time signal of an incoming FM broadcast , time information of an incoming GPS signal , time information of an incoming TV signal , via a telephone line time signal, the isolated operation detecting method according to claim 3, characterized in that any one of the synchronizing signals of the punctual signal, and power line communication over the Internet. There are a plurality of distributed power sources that are connected to the system power source, and a plurality of isolated operation detection devices that are arranged for each distributed power source and detect the isolated operation of the distributed power source when the power supply of the system power source is stopped. A system interconnection system that operates the plurality of distributed power sources in parallel with the system power source,
Each of the isolated operation detection devices,
Wherein detecting a system voltage between the dispersed type power supply and system power supply, and the system signal generating means for generating a line signal in synchronization with the predetermined phase of the system voltage,
An external synchronization signal receiving means for receiving an external synchronization signal from an external synchronization signal source;
Internally generating an internal synchronization signal that includes a phase advance signal and a phase delay signal in a predetermined pattern based on the system signal generated by the system signal generation means and the external synchronization signal received by the external synchronization signal reception means Synchronization signal generating means;
Disturbance signal applying means for applying a disturbance signal to the system voltage based on the internal synchronization signal generated by the internal synchronization signal generating means,
Detecting a disturbance signal included in the system voltage by the grid interconnection point between the dispersed type power supply and system power supply, based on the detection result, possess a single operation determining means for determining the isolated operation of the dispersed type power supply ,
The internal synchronization signal generating means;
When a high-level system signal is received from the system signals synchronized with a predetermined phase of the system voltage at the detection timing of the external synchronization signal, an internal synchronization signal starting from a phase advance signal is generated corresponding to the high-level system signal As well as
When a low-level system signal is received among the system signals synchronized with a predetermined phase of the system voltage at the detection timing of the external synchronization signal, the system signal becomes the high-level system signal at the timing when the next high-level system signal is received. Configured to generate an internal synchronization signal starting from the corresponding phase advance signal,
System interconnection system characterized by that. Said external synchronizing signal receiving means, the time information of the radio clock signals arriving, time signal of the AM broadcast arrives, ping signal of FM broadcast arrives, the time information of the incoming GPS signals, the time information of the incoming television signal, a telephone time signal via line, the grid interconnection system according to claim 5, wherein punctual signal over the Internet, and that the power line communication any one of the synchronizing signals, characterized in that received as the external synchronizing signal.

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