JPH09135535A - Static-type reactive power compensator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to control a power factor or reactive power to a constant value even if the power flow changes. SOLUTION: This equipment is provided with a second current transformer 4 which is inserted in a distribution line or feed line 1 and a first current transformer 7 which detects the input current of a main circuit 2 which generates reactive power ranging from leading one to lagging one. A power flow direction detecting means 8 detects the direction of the power flow from the outputs of a transformer 3 and the second current transformer 4. An arithmetic means 9 outputs the output of the second current transformer 4 when the power is flowing forward and outputs an added value of the reverse output of the second current transformer 4 and the output of the first current transformer when the power is flowing reversely. A controlling means 6 receives the outputs of the transformer 3 and the arithmetic means 9 and finds a power factor or reactive power from the outputs of the second current transformer 4 and the transformer 3 when the power is flowing forward and from an added value of the reverse output of the second current transformer 4 and the output of the first current transformer 7 and the output of the transformer 3 when the power is flowing reversely. The controlling means 6 controls the main circuit 2 so that the power factor or reactive power becomes a target value which is set by a target value setting means 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a static var compensator for constant control of power factor or reactive power of a distribution line or a transmission line.

[0002]

2. Description of the Related Art In recent years, since various electric devices are used, it is becoming more and more important to improve the power factor of distribution lines or transmission lines.

A conventional reactive power compensator will be described below with reference to the drawings. FIG. 7 is a block diagram showing the configuration of a conventional reactive power guarantee device. A static var compensator is used for the purpose of suppressing the power loss of the distribution line or the transmission line, and the reactive power output is controlled so that the power factor of the distribution line or the transmission line is near 1 or the reactive power is near zero. It's controlled to keep. In FIG. 7, 1 is a distribution line or transmission line, 2 is a plurality of reactors and a plurality of capacitors, and 1
A main circuit 3 composed of one or a plurality of series-connected thyristors and an anti-parallel circuit of the thyristors to generate reactive power from advanced to delayed by controlling the conduction angle of the thyristors. And a second transformer for detecting the current flowing in the distribution line or the transmission line 1 together with the phase, and 5 are target values of the power factor or reactive power of the distribution line or the transmission line 1. A target value setting means 6 for calculating the power factor or reactive power of the distribution line or the power transmission line 1 is calculated, and the reactive power generated by the main circuit 2 is controlled so that the value becomes the target value. It is a control means.

In the above structure, the control means 6 controls the distribution line or the transmission line 1 from the output of the transformer 3 and the output of the second current transformer 4 inserted in the distribution line or the transmission line 1. By calculating the power factor or reactive power and controlling the conduction angle of the thyristor so that the value becomes the target value setting means, the power factor of the distribution line or the transmission line 1 is kept close to 1,
The power loss of the distribution line or the transmission line 1 is suppressed.

[0005]

In such a conventional reactive power compensator, in the actual distribution line or transmission line, when the power flow direction is reversed at the time of an accident, load interchange, or system change, The constant rate or reactive power could not be controlled continuously.

The present invention solves the above problems, and an object of the present invention is to provide a static var compensator capable of continuing constant power factor or reactive power control even if the power flow direction changes.

[0007]

According to a first aspect of the present invention, a main circuit which is connected to a distribution line or a transmission line and generates a reactive power from a lead to a delay and a voltage of the distribution line or the transmission line are detected. A transformer, a first current transformer that detects an input current of the main circuit, and a second current transformer that is inserted into the distribution line or the power transmission line closer to the power source than the connection point of the main circuit. And detecting the direction of the tidal current of the distribution line or the transmission line by the output of the second current transformer and the output of the transformer,
In the case of forward power flow, the power factor or reactive power is obtained from the output of the second current transformer and the output of the transformer, and in the case of reverse power flow, the output of the second current transformer is reversed. The power factor or the reactive power is obtained from the output obtained by adding the output of the first current transformer to the output and the output of the transformer, and the main circuit is controlled so that the value becomes the target value. It is a static var compensator for performing constant control of power factor or reactive power of the distribution line or transmission line regardless of the direction of power flow.

Thus, the power factor or the reactive power of the distribution line or the transmission line can be controlled to be constant regardless of the direction of the power flow. Further, the present invention according to claim 2 is a main circuit connected to a distribution line or a transmission line to generate a reactive power from a lead to a delay, a transformer for detecting a voltage of the distribution line or the transmission line, and the main circuit. A second current transformer inserted into the distribution line or the power transmission line on the load side with respect to the connection point of the main circuit, the second current transformer detecting the input current of the second current transformer. The direction of the power flow of the distribution line or the power transmission line is detected by the output of the current transformer and the output of the transformer, and in the case of forward power flow, the first current transformer is output to the output of the second current transformer. The power factor or reactive power is obtained from the output of the transformer and the output of the transformer, and in the case of reverse power flow, the output is reversed by the output of the second current transformer and the output of the transformer. Rate or reactive power, and controlling the main circuit so that the value becomes the target value. Ri is a static var compensator in which the power factor or reactive power of the power distribution lines or transmission lines regardless of the flow direction so that constant control.

Thus, the power factor or reactive power of the distribution line or the transmission line can be controlled to be constant regardless of the direction of the power flow. The present invention according to claim 3 is the main circuit, which is connected to a distribution line or a transmission line and generates a reactive power from a lead to a delay, a transformer for detecting the voltage of the distribution line or the transmission line, and the distribution line. Alternatively, a first current transformer inserted in the power transmission line on the power source side of the main circuit connection point and a second current transformer inserted in the distribution line or the power transmission line on the load side of the main circuit connection point. And a power flow direction of the distribution line or the transmission line is detected by the output of the first current transformer and the output of the transformer, and in the case of forward power flow, the power flow of the second current transformer is detected. The power factor or reactive power is obtained from the output and the output of the transformer, and in the case of reverse flow, the power factor or reactive power is obtained from the output of the second current transformer and the output of the transformer. By controlling the main circuit so that the value reaches the target value, Warazu wherein is the power factor or reactive power distribution lines or power lines a static var compensator apparatus adapted to constant control.

Thus, the power factor or the reactive power of the distribution line or the transmission line can be controlled to be constant regardless of the direction of the power flow.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention according to claim 1 detects a voltage of a distribution line or a transmission line, and a main circuit which is connected to a distribution line or a transmission line and generates reactive power from advance to delay. A transformer and a first for detecting the input current of the main circuit
Current transformer, a second current transformer inserted into the distribution line or the transmission line on the power supply side of the connection point of the main circuit, an output of the second current transformer, and an output of the transformer. And a power flow direction detecting means for detecting a power flow direction of the distribution line or the transmission line, a target value setting means for setting a target value of the power factor or reactive power of the distribution line or the transmission line, and the first variable The output of the current transformer and the output of the second current transformer are input, the output of the second current transformer is output when the power flow direction is the forward direction, and the output of the second current transformer is output when the power flow direction is the reverse direction. The calculation means for calculating and outputting the sum of the inverted output of the output polarity of the second current transformer and the output of the first current transformer, and the output of the transformer and the output of the calculation means Calculate the power factor or reactive power of the distribution line or transmission line, and the value matches the target value of the target value setting means. Control means for controlling the reactive power generated by the main circuit, the direction of the tidal current is detected by the tidal current direction detecting means, and the controlling means controls the second current transformer in the case of forward tidal current. The power factor or reactive power is obtained from the output and the output of the transformer, and in the case of reverse flow, the output obtained by adding the output of the first current transformer to the inverted output of the output of the second current transformer. And the output of the transformer to obtain the power factor or reactive power, and by controlling the main circuit so that the value becomes the target value set in the target value setting means, the power distribution or the reactive power is changed regardless of the power flow direction. It is a static var compensator that constantly controls the power factor or reactive power of an electric wire or a transmission line. Further, the present invention according to claim 2 is a main circuit that is connected to a distribution line or a transmission line and that generates a reactive power that is delayed from a lead, a transformer that detects a voltage of the distribution line or the transmission line, and the main circuit. A first current transformer that detects an input current of the circuit; a second current transformer that is inserted into the distribution line or the transmission line on the load side from a connection point of the main circuit; and the second current transformer Direction detecting means for detecting the direction of the flow of the distribution line or the transmission line by the output of the transformer and the output of the transformer, and a target value for setting the target value of the power factor or reactive power of the distribution line or the transmission line. The setting means, the output of the first current transformer and the output of the second current transformer are input, and when the flow direction is the forward direction, the output of the second current transformer and the first current transformer. Output from the current transformer of the second current transformer, and outputs the sum of the output of the current transformer of Calculating means for outputting an inversion signal of the polarity of, and the output of the transformer and the output of the calculating means to calculate the power factor or reactive power of the distribution line or the transmission line, and the value is the target of the target value setting means. A control means for controlling the reactive power generated by the main circuit so as to match the value, the power flow direction detection means detects the direction of the power flow, and the control means controls the second power flow in the case of forward power flow. The power factor or reactive power is obtained from the output of the current transformer and the output of the first current transformer and the output of the transformer, and in the case of reverse flow, the second
By obtaining the power factor or reactive power from the output of the current transformer and the output of the transformer, by controlling the main circuit so that the value becomes the target value set in the target value setting means. A static var compensator for constant control of the power factor or reactive power of the distribution line or the transmission line regardless of the flow direction. Further, the present invention according to claim 3 is
A main circuit that is connected to a distribution line or a transmission line and that generates a reactive power from a lead to a delay, a transformer that detects the voltage of the distribution line or the transmission line, and a connection point of the main circuit to the distribution line or the transmission line. Also the first current transformer inserted on the power supply side,
A second current transformer inserted into the distribution line or the transmission line on the load side of the connection point of the main circuit, and the output of the first current transformer and the output of the transformer, A power flow direction detecting means for detecting a power flow direction of the electric wire, a target value setting means for setting a target value of the power factor or the reactive power of the distribution line or the transmission line, an output of the first current transformer, and the second current
And the output of the current transformer, the output of the first current transformer is output when the power flow direction is forward, and the output of the second current transformer when the power flow direction is reverse. Calculating the power factor or reactive power of the distribution line or the transmission line by the output means of the transformer and the output of the transformer, so that the value matches the target value of the target value setting means. And a control means for controlling the reactive power generated by the main circuit, the direction of the tidal current is detected by the tidal current direction detecting means,
The control means obtains a power factor or reactive power from the output of the second current transformer and the output of the transformer in the case of forward power flow, and in the case of reverse power flow, the second current transformer. The power factor or reactive power by the output of the transformer and the output of the transformer,
By controlling the main circuit so that the value becomes the target value set in the target value setting means, a static type reactive device that constantly controls the power factor or reactive power of the distribution line or the transmission line regardless of the power flow direction It is a power compensator.

Hereinafter, embodiments of the present invention will be described. (Embodiment 1) An embodiment of a static var compensator of the present invention according to claim 1 will be described below with reference to the drawings. FIG. 1 is a circuit diagram showing the configuration of this embodiment. The same components as those of the conventional example shown in FIG. 7 are given the same numbers.

In the figure, 1 is a distribution line or power transmission line, 2
Is a main circuit consisting of a capacitor, a reactor, and a thyristor.When the thyristor is off, the reactive power is output by the capacitor, and as the conduction angle of the thyristor increases, the reactive power decreases, and when the thyristor becomes fully conductive, it becomes a reactor. A delayed reactive power corresponding to the difference from the capacitor capacity is generated, and by controlling the conduction angle of the thyristor, the reactive power from the lead to the delay is continuously controlled. Reference numeral 7 is a first current transformer for detecting an input current of the static var compensator, 8 is a power flow direction detecting means, and a voltage and a current obtained from the second current transformer 4 and the transformer 3 The power flow direction in the distribution line or the transmission line 1 is detected from. As a method of detecting the power flow direction, for example, active power is calculated, and when the value is positive, it can be determined as forward power flow and when it is negative, it can be determined as reverse power flow, and the phase difference between the phase voltage and current is ± 90
It can be judged that the flow is in the forward direction when the angle is within °, and the flow in the reverse direction when the angle is more than ± 90 °. The tidal current direction may be detected by other methods. Reference numeral 9 denotes a computing means, which outputs the signal of the second current transformer 4 installed in the distribution line or the power transmission line 1 to the control means 6 as it is when the tide is in the forward direction, and outputs the signal in the reverse direction. In this case, the sum of the inverted signal of the second current transformer 4 and the signal of the first current transformer 7 is calculated and output to the control means 6.

In the above structure, the tidal current direction detecting means 8 detects whether the tidal current direction is the forward direction or the backward direction and instructs the computing means 9 and the control means 6. When the power flow direction is the forward direction, the calculation means 9 gives the output of the second current transformer 4 to the control means 6 as it is, so that the control means 6 is the same as the conventional example. The power factor or the reactive power in the distribution line or the transmission line 1 is obtained from the output of 1 and the output of the transformer 3, and the main circuit 2 is controlled so that the power factor or the reactive power becomes the target value set in the target value setting means 5. When the power flow direction is the reverse direction, the calculating means 9 adds the inverted output of the second current transformer 4 and the output of the first current transformer 7 to generate the current on the power supply side during the reverse power flow. The value is output to the control means 6, the control means 6 obtains the power factor or reactive power at the time of reverse power flow, and the main circuit 2 of the main circuit 2 is set so that the power factor or reactive power set by the target value setting means 5 is reached. Control the thyristor.

In the present embodiment, FIG. 1 shows the case of a single-phase AC distribution line, but in a three-phase AC distribution line or a transmission line, the same configuration is used for each phase and the power factor or reactive power is used. It goes without saying that you can control it. FIG.
As shown in FIG. 5, the main circuit 2 may be a parallel circuit including a capacitor circuit and a thyristor circuit, which includes a reactor in series. A photocurrent sensor may be used as a current transformer attached to the distribution line or the power transmission line 1. The use of the photocurrent sensor is very advantageous in terms of construction method because it is not necessary to cut the electric wire.

(Second Embodiment) An embodiment of the static var compensator according to the present invention will be described below with reference to FIG. In addition, the same components as those in FIG. The difference from the present invention according to claim 1 is that the second current transformer 4 of the distribution line or the power transmission line 1 is installed on the load side, and the computing means 9 uses the second current transformer 4 when the tidal current is in the forward direction. The sum of the signal from the transformer 4 and the signal from the first current transformer 7 for detecting the input current of the static var compensator is output to the control means 6, and the second current transformer 4 in the case of reverse flow. The inversion signal of is output to the control means 6. In this case, the output of the second current transformer 4 is based on the output polarity during forward power flow.

In the above structure, the power flow direction detecting means 8
In the same manner as in the first embodiment, detects the direction of the tidal current and instructs the calculation means 9 and the control means 6. In the case of the forward power flow, the calculating means 9 calculates the sum of the output of the second current transformer 4 and the output of the first current transformer 7 so that the current during the forward power flow is sent to the control means 6. Then, the control means 6 obtains the power factor or the reactive power by the voltage output of the transformer 3 and the current, and controls the thyristor of the main circuit 2 so as to reach the target value set in the target setting means 5. In the case of reverse power flow, the calculation means 9 outputs the current at the time of reverse power flow to the control means 6 by the inversion signal of the second current transformer 4. The control means 6 obtains the power factor or reactive power from the current and the voltage output of the transformer 3, and controls the thyristor of the main circuit 2 so that the target value of the power factor or reactive power set in the target value setting means 5 becomes the target value. Control.

Although FIG. 2 shows the case of the single-phase AC distribution line in the present embodiment, in the case of the three-phase AC distribution line or the transmission line, the same configuration is used for each phase and the power factor or reactive power is used. It goes without saying that you can control it. FIG.
As shown in FIG. 5, the main circuit 2 may be a parallel circuit including a capacitor circuit and a thyristor circuit, which includes a reactor in series. A photocurrent sensor may be used as a current transformer attached to the distribution line or the power transmission line 1.

(Embodiment 3) An embodiment of the reactive power compensator of the present invention according to claim 3 will be described below with reference to the drawings. FIG. 3 is a block diagram showing the configuration of the present embodiment. The same components as those in FIGS. 1 and 2 are designated by the same reference numerals and the description thereof will be omitted. This embodiment is different from Embodiments 1 and 2 in that a distribution line or a transmission line 1 is provided with a second current transformer 4 on the power supply side and a first current transformer 7 on the load side. It is not installed in the input line of the static var compensator, and when the calculation means 9 is in the forward direction, the signal from the second current transformer 4 on the power supply side is controlled by the control means 6.
In the case of reverse power flow, the signal of the first current transformer 7 on the load side is output to the control means 6, and the second current transformer 4 and the first current transformer are simply used. Only the output switching operation of No. 7 is performed.

In the above structure, the power flow direction detecting means 8
In the same manner as in the first embodiment, detects the direction of the tidal current and instructs the calculation means 9 and the control means 6. The control means 6 uses the output of the second current transformer 4 and the output of the transformer 3 in the case of forward power flow, and the first current transformer 7 in the case of reverse power flow.
And the output of the transformer 3 determine the power factor or the reactive power, respectively, and control the thyristor of the main circuit 2 so that the target value of the power factor or the reactive power set by the target value setting means 5 is reached.

In the present embodiment, FIG. 3 shows the case of a single-phase AC distribution line, but in a three-phase AC distribution line or a transmission line, the same configuration is used for each phase and the power factor or reactive power is used. It goes without saying that you can control it. FIG.
As shown in FIG. 5, the main circuit 2 may be a parallel circuit including a capacitor circuit and a thyristor circuit, which includes a reactor in series. A photocurrent sensor may be used as a current transformer attached to the distribution line or the power transmission line 1.

[0022]

As is apparent from the above description, the power factor or reactive power control can be continuously and constantly controlled even if the direction of the power flow of the distribution line or the transmission line changes. Also,
If the current transformer is realized by a photocurrent sensor, it is not necessary to cut the electric wire, which is very advantageous in terms of construction method.

[Brief description of the drawings]

1 is a circuit diagram showing the configuration of an embodiment of a static var compensator of the present invention according to claim 1;

FIG. 2 is a circuit diagram showing a configuration of an embodiment of a static var compensator of the present invention according to claim 2;

FIG. 3 is a circuit diagram showing a configuration of an embodiment of a static var compensator of the present invention according to claim 3;

FIG. 4 is a circuit diagram showing the configuration of another embodiment of the static var compensator of the present invention according to claim 1;

FIG. 5 is a circuit diagram showing the configuration of another embodiment of the static var compensator of the present invention according to claim 2;

FIG. 6 is a circuit diagram showing the configuration of another embodiment of the static var compensator of the present invention according to claim 3;

FIG. 7 is a circuit diagram showing a configuration of a conventional static var compensator.

[Explanation of symbols]

 1 Distribution Line or Transmission Line 2 Main Circuit 3 Transformer 4 Second Current Transformer 5 Target Value Setting Means 6 Control Means 7 First Current Transformer 8 Tidal Current Direction Detecting Means 9 Computing Means

Claims (6)

[Claims] 1. A main circuit which is connected to a distribution line or a transmission line and which generates reactive power from leading to lagging, a transformer which detects the voltage of the distribution line or the transmission line, and an input current of the main circuit. And a second current transformer inserted into the distribution line or the power transmission line on the power source side with respect to the connection point of the main circuit.
Current transformer, a power flow direction detecting means for detecting the power flow direction of the distribution line or the transmission line by the output of the second current transformer and the output of the transformer, and the force of the distribution line or the transmission line. A target value setting means for setting a target value of the rate or the reactive power, an output of the first current transformer and an output of the second current transformer are input, and when the power flow direction is a forward direction, The output of the second current transformer is output, and when the power flow direction is the reverse direction, the sum of the inverted output of the polarity of the output of the second current transformer and the output of the first current transformer is calculated. The power factor or reactive power of the distribution line or the transmission line is calculated by the output means of the transformer and the output of the transformer and the output of the calculation means, and the value matches the target value of the target value setting means. And a control means for controlling the reactive power generated by the main circuit, More detecting the direction of power flow, control means, in the case of forward power flow determined power factor or reactive power by the output of the transformer and the output of the second current transformer,
In the case of reverse power flow, the power factor or reactive power is obtained from the output obtained by adding the output of the first current transformer to the inverted output of the output of the second current transformer and the output of the transformer, and By controlling the main circuit so that the value becomes the target value set in the target value setting means, static type reactive power that constantly controls the power factor or reactive power of the distribution line or the transmission line regardless of the power flow direction Compensation device. 2. A main circuit that is connected to a distribution line or a transmission line and that generates a reactive power from a lead to a delay, a transformer that detects the voltage of the distribution line or the transmission line, and an input current of the main circuit. A first current transformer and a second one inserted into the distribution line or the transmission line on the load side with respect to the connection point of the main circuit.
Current transformer, a power flow direction detecting means for detecting the power flow direction of the distribution line or the transmission line by the output of the second current transformer and the output of the transformer, and the force of the distribution line or the transmission line. A target value setting means for setting a target value of the rate or the reactive power, an output of the first current transformer and an output of the second current transformer are input, and when the power flow direction is a forward direction, The sum of the output of the second current transformer and the output of the first current transformer is output, and when the power flow direction is the reverse direction, an inverted signal of the polarity of the output of the second current transformer is output. Calculating means for calculating the power factor or reactive power of the distribution line or the transmission line by the output of the transformer and the output of the calculating means, and the value is matched with the target value of the target value setting means. A control means for controlling the reactive power generated by the main circuit is provided, and the tide is detected by the tide direction detection means. Detecting the direction and control means,
In the case of forward power flow, the power factor or reactive power is obtained from the output of the second current transformer plus the output of the first current transformer and the output of the transformer to determine the reverse power flow. In this case, the power factor or the reactive power is obtained from the inverted output of the output of the second current transformer and the output of the transformer, and the main circuit is adjusted so that the value becomes the target value set in the target value setting means. The static var compensator for controlling the power factor or the reactive power of the distribution line or the power transmission line irrespective of the power flow direction by controlling. 3. A main circuit connected to a distribution line or a transmission line to generate a reactive power from a lead to a delay, a transformer for detecting a voltage of the distribution line or the transmission line, and the main circuit connected to the distribution line or the transmission line. A first current transformer inserted on the power supply side of the connection point of the circuit; a second current transformer inserted on the distribution line or the transmission line on the load side of the connection point of the main circuit; And a power flow direction detection means for detecting the power flow direction of the distribution line or the transmission line by the output of the current transformer and the output of the transformer, and the target value of the power factor or reactive power of the distribution line or the transmission line. Target value setting means, the output of the first current transformer and the output of the second current transformer are input, and the output of the first current transformer is output when the flow direction is forward. Then
When the power flow direction is in the opposite direction, calculation means for outputting the output of the second current transformer, and the output of the transformer and the output of the calculation means calculate the power factor or reactive power of the distribution line or the transmission line. And a control means for controlling the reactive power generated by the main circuit so that the value matches the target value of the target value setting means, the power flow direction detecting means detects the direction of the power flow, and the control means Is the power factor or reactive power obtained from the output of the second current transformer and the output of the transformer in the case of forward power flow, and the output of the second current transformer in the case of reverse power flow. By determining the power factor or reactive power by the output of the transformer and the transformer, by controlling the main circuit so that the value becomes the target value set in the target value setting means,
A static var compensator for constant control of the power factor or reactive power of the distribution line or transmission line regardless of the direction of power flow. 4. A first series circuit of the first reactor and a capacitor is connected in parallel with a second series circuit of a second reactor and an antiparallel circuit of one or more series thyristors. The static var compensator according to claim 1, further comprising a main circuit configured to generate a reactive power from leading to lag by controlling a conduction angle of the thyristor. 5. A first reactor and a first capacitor
Is connected in series to a parallel circuit of a second series circuit of an anti-parallel circuit of one or a plurality of second reactors and one or more series of second reactors, and a conduction angle of the thyristor. The static var compensator according to any one of claims 1 to 3, further comprising a main circuit that generates a reactive power from a lead to a lag. 6. A first current transformer and a second current transformer using a photocurrent sensor.
The static var compensator according to any one of claims 1 to 5, which constitutes either one or both of the current transformers.