JPH07160346A - Stationary reactive power compensator - Google Patents

Abstract

PURPOSE:To improve the response, improve the control performance, and secure the high reliability of the stationary reactive power compensator. CONSTITUTION:A 1st reactor 1, a 2nd reactor 2 and a capacitor 3 is connected in serves to a three-phase distribution line or power transmission line 6 to form a Y-connection, and a thyristor circuit 4 is connected to the connection point between the 1st reactor 1 and 2nd reactor 2 to form a DELTA-connection to constitute a main circuit; when reactive power is controlled continuously from a lagging state to a leading state by controlling the ignition angle of the thyristor circuit 4, a feedback loop is constituted with an effective value of an inter- phase voltage detected by an effective value detecting circuit 11 connected to a PT 7 to enable voltage constant control even over a distorted wave voltage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a static type system in which a thyristor circuit is controlled in a power system to which a load that causes fluctuations in reactive power is connected to compensate for fluctuations in reactive power that occur when the load is operated. The present invention relates to a reactive power compensator.

[0002]

2. Description of the Related Art Generally, in a power system to which a load whose reactive power fluctuates greatly is connected, the voltage at the connection point of the load fluctuates according to the reactive current flowing in the load.
It may adversely affect other power consumers connected to the same grid. A static var compensator is installed to suppress such voltage fluctuations.

FIG. 6 shows a connection diagram of a conventional static var compensator. Reference numeral 1 is a first reactor, 2 is a second reactor, 3 is a capacitor, 4 is a thyristor circuit having one or a plurality of anti-parallel circuits with adjustable conduction angles, and 5 is a thyristor gate signal. Thyristor drive circuit, 6 is a distribution line or transmission line to which a static var compensator is connected, 7 is a transformer (hereinafter referred to as PT) that detects the voltage of the distribution line or transmission line 6, and 8 is full-wave rectification Reference numeral 9 denotes a circuit, 9 is a timing detection circuit for detecting the timing of zero crossing of the interphase voltage of the distribution line or the transmission line 6, and 10
Is an arithmetic circuit.

Next, the main circuit operation of the static var compensator comprising the above components will be described. In FIG. 6, when the thyristor circuit 4 is stopped, the main circuit is a simple series circuit of the reactors 1 and 2 and the capacitor 3, so that the terminal voltage VC of the capacitor 3 becomes maximum, and the terminal voltage VR1 of the first reactor 1 and the second voltage Since the terminal voltage VR2 of the reactor 2 becomes minimum, the advanced reactive power becomes maximum.
On the other hand, the thyristor drive circuit 5 causes the thyristor circuit 4
If the control circuit is turned on from the zero cross point of each interphase voltage at a control angle with a time advance direction, the second reactor 2 and the capacitor 3 are short-circuited for that period, and the terminal voltage VR1 of the first reactor 1 rises. Therefore, the leading reactive power supplied by the capacitor 3 becomes smaller and the delayed reactive power due to the first reactor 1 increases. In addition, due to the conduction of the thyristor circuit 4, the charge of the capacitor 3 becomes the second charge.
Inverted charge is performed through the reactor 2 and the thyristor circuit 4, and this inverted charge is generated after the thyristor circuit 4 is turned off.
It flows into the distribution line or the power transmission line 6 as a lag phase current and generates delayed reactive power. If the delay control angle of the thyristor circuit 4 is further advanced, then the overall reactive power decreases and the delayed reactive power increases. In this way, the thyristor circuit 4
By controlling the phase of, it is possible to continuously control from the advanced reactive power to the delayed reactive power.

Next, the operation of constant phase-to-phase voltage control of a distribution line or a transmission line by controlling such a main circuit will be described. The interphase voltage of the distribution line or transmission line 6 is PT7.
Is detected by the full-wave rectifier circuit 8 and converted into a feedback signal of interphase voltage. The error signal between the feedback signal of the interphase voltage and the voltage command value is processed by the arithmetic circuit 10 to obtain the firing timing command value of the thyristor drive circuit 5. In the thyristor drive circuit 5, according to the ignition timing command value of the arithmetic circuit 10, for example, when the interphase voltage is higher than the voltage command value, the static var compensating is performed by shifting the ignition timing of the thyristor forward from the zero cross point of the interphase voltage. The operating point of the device is controlled so as to shift to the delay side, and the feedback control is performed so that the interphase voltage decreases and matches the voltage command value. Conversely, when the interphase voltage is lower, the ignition timing of the thyristor is brought closer to the zero crossing point of the interphase voltage, and the operating point of the static var compensator is controlled so as to shift to the advanced side. Feedback control is performed to match the command value.

As described above, the static var compensator for the static var compensator is provided by using the interphase voltage of the distribution line or the transmission line as the feedback signal, and controlling the phase of the thyristor circuit 4 so that the voltage command value matches the interphase voltage feedback signal. By continuously controlling the reactive power of the above from delay to advance, the interphase voltage of the distribution line or transmission line at the installation point of the static var compensator can be kept constant.

[0007]

Since the conventional static var compensator has the above-mentioned structure, first of all, since the interphase voltage of the distribution line or the transmission line is full-wave rectified into the feedback signal, When the interphase voltage includes a distorted wave, an error occurs in the constant voltage control.

Secondly, since the control circuit of the conventional example has only the feedback loop of the interphase voltage, a large thyristor current may flow and destroy the thyristor when the interphase voltage fluctuates greatly and the voltage error signal becomes large. There is.

Thirdly, in the conventional example, there is a possibility that the control circuit is cut off immediately after the power source is turned on, in which case the static var compensator will be started up with 100% advance or delay. Then, there is a possibility that the interphase voltage of the distribution line or the transmission line may abnormally rise or fall.

Fourthly, since the conventional example is basically based on the voltage feedback control, there is a limit in the responsiveness to a sudden change in the interphase voltage. The present invention has been made to solve each of the above problems, and an object thereof is to provide a static var compensator capable of improving responsiveness, improving control performance, and ensuring high reliability. To do.

[0011]

In order to solve the above first problem, the present invention provides a series connection of a first reactor, a second reactor and a capacitor, which are Y-connected to a three-phase distribution line or a transmission line, for example. A circuit, the first reactor and the second
Attached to the distribution line or the transmission line, and a main circuit composed of three thyristor circuits consisting of one or more series-connected thyristor anti-parallel circuits, which are Δ-connected to three connection points of each phase of the reactor. PT, an effective value detection circuit that detects the effective value of the output of the PT, and a timing detection circuit that receives the output of the PT and detects the zero-cross timing of the interphase voltage of the distribution line or the transmission line,
A first arithmetic circuit that receives an error signal between the output signal of the effective value detection circuit and a preset voltage command value, and an output signal of the first arithmetic circuit and an output of the timing detection circuit And a thyristor drive circuit that outputs a gate signal for controlling the conduction angle of the thyristor circuit.

In order to solve the above-mentioned second problem, the present invention provides, for example, a series circuit of a first reactor, a second reactor and a capacitor, which are Y-connected to a three-phase distribution line or a power transmission line, and the first circuit. And a main circuit composed of three thyristor circuits each consisting of an anti-parallel circuit of one or more series thyristors Δ-connected to three connection points of each phase of the second reactor, and the distribution line or A PT attached to the power transmission line, an effective value detection circuit for detecting the effective value of the output of the PT, and a timing detection for detecting the zero-cross timing of the interphase voltage of the distribution line or the transmission line with the output of the PT as an input. A circuit, a CT installed between the first reactor and the distribution line or the power transmission line for detecting an input current of the main circuit, the PT and the CT
Of the reactive power detection circuit for detecting the reactive power flowing into the main circuit by inputting the output signal of the above, and the error signal between the output signal of the voltage effective value detection circuit and the preset voltage command value as the input. An arithmetic circuit; a limiter that receives the output signal of the first arithmetic circuit; a second arithmetic circuit that receives the error signal between the output of the limiter and the output signal of the reactive power detection circuit; And a thyristor drive circuit which receives the output signal of the arithmetic circuit and the output signal of the timing detection circuit and outputs a gate signal for controlling the conduction angle of the thyristor circuit.

As another method for solving the above-mentioned second problem, the present invention provides, for example, a series connection of a first reactor, a second reactor and a capacitor Y-connected to a three-phase distribution line or a transmission line. A main circuit composed of a circuit and three thyristor circuits consisting of an anti-parallel circuit of one or a plurality of series thyristors Δ-connected to three connection points of each phase of the first reactor and the second reactor A PT attached to the distribution line or the power transmission line;
An effective value detection circuit for detecting an output effective value of the PT, a timing detection circuit for detecting the zero-cross timing of the interphase voltage of the distribution line or the transmission line using the output of the PT as an input, and the thyristor circuit. CT
A thyristor current detection circuit that receives the CT output signal as an input and detects the current value flowing in the thyristor circuit; and an error signal between the output signal of the voltage effective value detection circuit and a preset voltage command value as an input. A first arithmetic circuit, a limiter that receives the output signal of the first arithmetic circuit, and a second signal that receives the error signal between the output signal of the limiter and the output signal of the thyristor current detection circuit.
And the thyristor drive circuit which receives the output signal of the second arithmetic circuit and the output signal of the timing detection circuit and outputs a gate signal for controlling the conduction angle of the thyristor circuit.

In order to solve the above-mentioned third problem, the present invention provides, for example, a series circuit of a first reactor, a second reactor and a capacitor, which are Y-connected to a three-phase distribution line or a transmission line, and the first circuit. And a main circuit composed of three thyristor circuits each consisting of an anti-parallel circuit of one or more series thyristors Δ-connected to three connection points of each phase of the second reactor, and the distribution line or A PT attached to the power transmission line, an effective value detection circuit for detecting the effective value of the output of the PT, and a timing detection for detecting the zero-cross timing of the interphase voltage of the distribution line or the transmission line with the output of the PT as an input. A circuit, a CT installed between the first reactor and the distribution line or the power transmission line for detecting an input current of the main circuit, the PT and the CT
Of the reactive power detection circuit for detecting the reactive power flowing into the main circuit by inputting the output signal of the above, and the error signal between the output signal of the voltage effective value detection circuit and the preset voltage command value as the input. An arithmetic circuit, a second arithmetic circuit which receives an error signal between an output signal of the first arithmetic circuit and an output signal of the reactive power detection circuit, an output signal of the second arithmetic circuit and the timing detection A thyristor drive circuit that receives a circuit output signal as an input and outputs a gate signal that controls the conduction angle of the thyristor circuit, a power supply rise detection circuit, and an output signal of the power supply rise detection circuit as an input, and a certain time after the power supply rises. A timer that counts only once, the timer that receives the output of the timer, the input signal of the thyristor drive circuit, and the output signal of the reactive power detection circuit as input A second arithmetic circuit configured to store an input signal of the thyristor drive circuit when the reactive power is near 0 Var in a normal operation state after time-up and to retain the stored content even when the power is off. Is
In addition to the error signal between the output signal of the first arithmetic circuit and the output signal of the reactive power detection circuit, the output signal of the storage device and the output signal of the timer are further input, and after the power is turned on, the timer The thyristor drive circuit is configured to output an output signal in which the reactive power stored in the storage circuit is close to 0 Var until the time is up, and to perform normal arithmetic processing after the timer is up. The conduction angle of the circuit is controlled, and the reactive power flowing in the main circuit is continuously controlled to perform constant voltage control of the distribution line or the transmission line.

In order to solve the above-mentioned fourth problem, the present invention provides, for example, a series circuit of a first reactor, a second reactor and a capacitor, which are Y-connected to a three-phase distribution line or a transmission line, and the first circuit. And a main circuit composed of three thyristor circuits each consisting of an anti-parallel circuit of one or more series thyristors Δ-connected to three connection points of each phase of the second reactor, and the distribution line or A PT attached to the power transmission line, an effective value detection circuit for detecting the effective value of the output of the PT, and a timing detection for detecting the zero-cross timing of the interphase voltage of the distribution line or the transmission line with the output of the PT as an input. A circuit, a first CT installed between the first reactor and the distribution line or the transmission line to detect an input current of the main circuit, and outputs of the PT and the first CT Signal as an input, a reactive power detection circuit for detecting reactive power flowing into the main circuit, a second CT attached to the distribution line or the transmission line on the load side of the CT, an output signal of the PT, and the An active power change detecting circuit which receives an output signal of the second CT and detects a change in active power of the distribution line or the transmission line;
A reactive power change amount detection circuit that receives the output signal of T and the output signal of the second CT and detects the change amount of the reactive power of the distribution line or the transmission line, and the distribution line or the transmission line of the distribution line to the local point. A line constant storage circuit that stores a line constant, a third arithmetic circuit that receives the active power change detection circuit, the reactive power change detection circuit, and the line constant storage circuit, and the voltage effective value detection circuit. Of the first arithmetic circuit that receives the error signal between the output signal of the second arithmetic circuit and the preset voltage command value, the output signal of the third arithmetic circuit, and the first arithmetic circuit.
An adder circuit that receives the output signal of the calculator circuit as an input; a second calculator circuit that receives the error signal between the output signal of the adder circuit and the output signal of the reactive power detection circuit; and the second calculator circuit. Input signal and the output signal of the timing detection circuit, and outputs a gate signal for controlling the conduction angle of the thyristor circuit.

[0016]

The present invention has the following functions due to the above-mentioned constitution. First, the voltage constant control of the distribution line or the transmission line can be accurately performed regardless of the distortion of the interphase voltage. Secondly, by providing a feedback loop for the thyristor current or reactive power and setting the upper limit of the current of the main circuit, it is possible to prevent the thyristor from being destroyed. Third, 0V when power is restored after power failure
The static var compensator can be activated from the operating point of ar to prevent transient abnormal voltage. Fourthly, when the voltage of the distribution line or the power transmission line suddenly changes, reactive power that suppresses the sudden voltage change can be generated to quickly correct the voltage variation.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a connection diagram showing a configuration of a first embodiment of a static var compensator according to the present invention. Reference numeral 1 is a first reactor, 2 is a second reactor, 3 is a capacitor, and a series circuit in which they are connected in series is connected in a Y shape and connected to a three-phase distribution line or a transmission line 6. , Δ at the connection point of the first reactor and the second reactor
Together with the three thyristor circuits 4 connected in series, they constitute the main circuit of the static var compensator. 7 is a transformer (hereinafter PT) for detecting the interphase voltage of the distribution line or the transmission line 6.
, 11 is an effective value detection circuit that receives the PT7 output as an input and obtains an effective value output. 10 is an arithmetic circuit for inputting an error signal between the voltage command value and the effective value output of the effective value detection circuit and outputting a command signal for thyristor drive. 5 is an input circuit for the command signal for thyristor drive, and is detected by the timing detection circuit 9 The thyristor drive circuit outputs an ignition signal of the thyristor circuit 4 with reference to the zero-cross point of the interphase voltage. When the operating point of the static var compensator is moved to the delay side by the thyristor drive circuit 5, the ignition signal of the thyristor circuit 4 is shifted forward with respect to the zero cross point of the interphase voltage as a starting point. When moving to the lead side, return to the zero-cross point of the interphase voltage.

By the way, there is a long distribution line or transmission line 6 between the substation or power plant and the installation point of the static var compensator, and there is an inductance component. Therefore, when the static var compensator operates on the lead side, the voltage at the installation point rises, and conversely, when it operates on the delay side, the voltage at the installation point drops.

Therefore, if the operating point of the static var compensator is controlled so that the error signal between the voltage command value and the feedback value of the interphase voltage of the distribution line or the transmission line becomes zero, the distribution line at the installation point or It is possible to control the phase-to-phase voltage of the transmission line constantly.

Conventionally, the detection of the feedback voltage has been performed by full-wave rectification, but if a distorted wave is superimposed on the interphase voltage of the distribution line or the transmission line, an error occurs in the constant voltage control. . However, in this embodiment, the error due to the waveform distortion could be reduced by feeding back the effective voltage.

In the present embodiment, the example in which the signal processing is performed by the electronic circuit is presented in the block diagram, but the signal processing of the feedback control can be realized by the software processing of the microcomputer.

Next, a second embodiment of the static var compensator of the present invention will be described with reference to FIG. The main circuit is the same as that of the first embodiment, so its explanation is omitted. However, a current transformer (hereinafter referred to as CT) 16 for detecting the input current of the static var compensator is installed at the connection point between the static var compensator and the distribution line or the transmission line 6. The reactive power detection circuit 15 detects the reactive power of the static var compensator based on the CT output signal and the PT7 output signal. On the other hand, the error signal between the voltage command value and the feedback value of the interphase voltage of the distribution line or the transmission line 6 is used as the first arithmetic circuit 1
3 is input to obtain the reactive power command value of the static var compensator. The upper and lower limit values of this reactive power command value are set through the limiter 14, and the reactive signal is compared with the reactive power feedback signal from the reactive power detection circuit 15, and its error signal is input to the second arithmetic circuit 12, and its output signal is used as a thyristor. The firing angle of the thyristor circuit 4 is controlled via the drive circuit 5.
Since the upper and lower limits are set to the reactive power command value by the limiter 14, the upper and lower limits of the input current and thyristor current of the static var compensator can be set as a result, and the overcurrent of the main circuit components can be reduced. It can be prevented. Regarding the function of the constant voltage control, since the voltage feedback loop is provided outside the reactive power feedback loop, the constant voltage control can be realized by the same operation principle as that of the first embodiment.

In the present embodiment, an example in which the signal processing is performed by an electronic circuit is presented in a block diagram, but the signal processing of the feedback control can also be realized by software processing of a microcomputer.

Next, a third embodiment of the static var compensator of the present invention will be described with reference to FIG. This is almost the same configuration as the second embodiment, and the difference is that the installation location of CT17 is installed in series with the thyristor circuit 4, and this CT
The thyristor current is detected by the thyristor current detection circuit 17 and the thyristor current detection circuit 18 and used as a feedback value of the thyristor current. On the other hand, the error signal between the voltage command value and the feedback value of the interphase voltage of the distribution line or the transmission line 6 is input to the first arithmetic circuit 13 to obtain the thyristor current command value of the static var compensator. The upper and lower limit values of this thyristor current command value are set through the limiter 14, and the error signal compared with the thyristor current feedback signal from the thyristor current detection circuit 18 is input to the second arithmetic circuit 12, and the output signal thereof is used as the thyristor drive circuit. The firing angle of the thyristor circuit 4 is controlled via 5. Since the limiter 14 sets the upper and lower limit values to the thyristor command value, as a result, the upper and lower limit values of the thyristor current of the static var compensator can be set, and indirectly the overcurrent of the main circuit component parts can be set. It can be prevented. Regarding the function of the constant voltage control, since the voltage feedback loop is provided outside the thyristor current feedback loop, the constant voltage control can be realized by the same operation principle as that of the first embodiment.

In the present embodiment, the example in which the signal processing is performed by the electronic circuit is presented in the block diagram, but the signal processing of the feedback control can be realized by the software processing of the microcomputer.

Next, a fourth embodiment of the static var compensator of the present invention will be described with reference to FIG. This is almost the same configuration as that of the second embodiment. The difference is that the power supply rise detection circuit 21, the timer 20 that measures a certain time after the power supply rises, the output signal of the reactive power detection circuit 15, and the timer 20. The storage circuit 19 that receives the output signal and the output signal of the second arithmetic circuit 12 as an input and sends the output signal to the second arithmetic circuit is a new component. The timer 20 determines whether or not a certain time has passed since the power was turned on. In other words, is the control circuit of the static var compensator in the transient state immediately after the power is turned on?
When it is in the steady state, the storage circuit 19 stores the command signal level to the thyristor drive circuit 5 when the reactive power is 0 Var. The storage circuit 19 uses a non-volatile memory or performs battery backup so that the stored contents are not lost even when the power is off. When the control circuit of the static var compensator immediately after the power is restored is in a transient state, the operating point of the static var compensator previously stored in the memory circuit 19 is 0.
A command value to the thyristor drive circuit that results in Var is output through the second arithmetic circuit 12 so that the static var compensator performs 0Var operation without swinging. After that, when the control circuit of the static var compensator is in a steady state, it is switched to normal feedback control. Since the reactive power feedback loop and the voltage feedback loop in the steady state are exactly the same as those described in the first and second embodiments, the description thereof will be omitted.

Although the present embodiment is shown in the block diagram on the assumption that the signal processing is performed by the electronic circuit, the signal processing for each control can be realized by the software processing of the microcomputer.

Next, a fifth embodiment of the static var compensator of the present invention will be described with reference to FIG. This is almost the same configuration as the second embodiment, the difference is that the second CT22 installed on the load side of the distribution line or transmission line power supply,
Active power change detection circuit 23, reactive power change detection circuit 24, line constant storage circuit 25, and third arithmetic circuit 26, which detect changes in active power and reactive power of the load, respectively.
And the addition circuit 27 is added. Second CT2
2 and ΔQ are the changes in the active power and the reactive power detected by the active power change detection circuit 23 and the reactive power change detection circuit 24 from the outputs of PT7 and PT7, respectively, and the resistance of the distribution line or the transmission line 6 and Inductance components are R and L respectively
Then, the reactive power Qs of the static var compensator for suppressing the fluctuation of the interphase voltage at the installation point of the static var compensator is given by the equation (1).

Qs = ΔQ + ΔP × (R / L) (1) Therefore, the resistance component and the inductance component of the distribution line or the transmission line 6 from the substation or power plant to the local point are stored in the line constant storage circuit 25 and stored. The third arithmetic circuit 26 calculates the equation (1) to calculate the reactive power command value for compensating the fluctuation of the interphase voltage at the installation point of the static var compensator due to the sudden change of the load, and the adding circuit 27 And the first arithmetic circuit 1
By adding the reactive power command value from 3 and Qs, a reactive power command signal that can cope with a sudden change in load is obtained. Thus, according to this embodiment, a sudden change in load is detected,
The open-loop control is performed by calculating the output of the static var compensator required to compensate for voltage fluctuations in consideration of the distribution line or transmission line constants, so voltage fluctuations can be suppressed faster. You can Since the reactive power feedback loop and the voltage feedback loop in the steady state are exactly the same as those described in the first and second embodiments, the description thereof will be omitted.

In the present embodiment, the case where the signal processing is performed by the electronic circuit is assumed and presented in the block diagram, but the signal processing for each control can be realized by the software processing of the microcomputer.

Further, in the description of each embodiment, the second reactor 2 and the capacitor 3 of the main circuit of the static var compensator have been described as an example of Y-type connection, but the reactor and the capacitor are Δ-connection. It doesn't matter. Further, although the present embodiment has been described with respect to the three-phase circuit, it goes without saying that it can be applied to the single-phase circuit.

[0032]

As is apparent from the above description, according to the present invention, the following effects can be obtained. First,
First, the voltage constant control of the distribution line or the transmission line can be accurately performed regardless of the distortion of the interphase voltage. Therefore, it is very effective for voltage stabilization in the situation where harmonics of distribution lines or transmission lines increase and voltage distortion cannot be ignored like today. Secondly, a thyristor current or reactive power feedback loop is provided, and the upper limit of the current of the main circuit is set to prevent destruction of the thyristor. As a result, it is possible to ensure the high reliability required for equipment of the distribution system or the transmission system. Third, 0V when power is restored after power failure
The static var compensator can be activated from the operating point of ar to prevent transient abnormal voltage. Fourthly, when the voltage of the distribution line or the power transmission line suddenly changes, reactive power that suppresses the sudden voltage change can be generated to quickly correct the voltage variation.

[Brief description of drawings]

FIG. 1 is a connection diagram of a static var compensator according to a first embodiment of the present invention.

FIG. 2 is a connection diagram of a static var compensator according to a second embodiment of the present invention.

FIG. 3 is a connection diagram of a static var compensator according to a third embodiment of the present invention.

FIG. 4 is a connection diagram of a static var compensator according to a fourth embodiment of the present invention.

FIG. 5 is a connection diagram of a static var compensator according to a fifth embodiment of the present invention.

FIG. 6 is a connection diagram of a conventional static var compensator.

[Explanation of symbols]

 1 1st reactor 2 2nd reactor 3 Capacitor 4 Thyristor circuit 5 Thyristor drive circuit 6 Distribution line or transmission line 7 Instrument transformer 8 Full-wave rectifier circuit 9 Timing detection circuit 10 Arithmetic circuit 11 Effective value detection circuit 12 2nd Operation circuit 13 First operation circuit 14 Limiter 15 Reactive power detection circuit 16, 17 Current transformer 18 Thyristor current detection circuit 19 Memory circuit 20 Timer 21 Power supply rise detection circuit 22 Second current transformer 23 Active current change detection Circuit 24 Reactive power change detection circuit 25 Line constant memory circuit 26 Third arithmetic circuit 27 Adder circuit

Claims (5)

[Claims] 1. A first reactor connected to a distribution line or a transmission line, a series circuit of a second reactor and a capacitor, and one connected to a connection point of the first reactor and the second reactor. Alternatively, a main circuit composed of a thyristor circuit composed of an antiparallel circuit of a plurality of thyristors in series, a transformer (hereinafter referred to as PT) attached to the distribution line or the transmission line, and an effective value of the output of the PT. , A timing detection circuit for detecting the zero-crossing timing of the phase-to-phase voltage of the distribution line or the transmission line using the output of the PT as an input, and an output signal of the RMS value detection circuit set in advance. A first arithmetic circuit that receives an error signal from a voltage command value, and an output signal of the first arithmetic circuit and an output of the timing detection circuit that are input to the thyristor. A thyristor drive circuit that outputs a gate signal that controls the conduction angle of the circuit, and controls the conduction angle of the thyristor circuit to continuously control the reactive power that flows in the main circuit to keep the voltage of the distribution line or the transmission line constant. A static var compensator designed to perform control. 2. A first reactor connected to a distribution line or a transmission line, a series circuit of a second reactor and a capacitor, and one connected to a connection point of the first reactor and the second reactor. Alternatively, a main circuit composed of a thyristor circuit composed of an anti-parallel circuit of a plurality of serial thyristors, and a PT attached to the distribution line or transmission line.
An effective value detection circuit that detects an effective value of the PT output; a timing detection circuit that receives the output of the PT and detects a zero-cross timing of the interphase voltage of the distribution line or the transmission line; A current transformer (hereinafter referred to as CT) that is installed between a reactor and the distribution line or the transmission line and detects an input current of the main circuit, the PT and the CT.
Of the reactive power detection circuit for detecting the reactive power flowing into the main circuit by inputting the output signal of the above, and the error signal between the output signal of the voltage effective value detection circuit and the preset voltage command value as the input. An arithmetic circuit; a limiter that receives the output signal of the first arithmetic circuit; a second arithmetic circuit that receives the error signal between the output of the limiter and the output signal of the reactive power detection circuit; And a thyristor drive circuit that outputs a gate signal that controls the conduction angle of the thyristor circuit by using the output signal of the second arithmetic circuit and the output signal of the timing detection circuit as input, and controls the conduction angle of the thyristor circuit. A static var compensator for continuously controlling reactive power flowing in a circuit to perform constant voltage control of the distribution line or the transmission line. 3. A first reactor connected to a distribution line or a transmission line, a series circuit of a second reactor and a capacitor, and one connected to a connection point of the first reactor and the second reactor. Alternatively, a main circuit composed of a thyristor circuit composed of an anti-parallel circuit of a plurality of serial thyristors, and a PT attached to the distribution line or transmission line.
An effective value detection circuit for detecting the effective value of the output of the PT, a timing detection circuit for detecting the zero-cross timing of the interphase voltage of the distribution line or the transmission line using the output of the PT as an input, and the thyristor circuit. A CT mounted in series, a thyristor current detection circuit that receives an output signal of the CT and detects a current value flowing in the thyristor circuit, an output signal of the voltage effective value detection circuit, and a preset voltage command value. Of the error signal of the first thyristor current detecting circuit and the output signal of the first arithmetic circuit, the limiter receiving the output signal of the first arithmetic circuit, and the output signal of the thyristor current detection circuit And an output signal of the second arithmetic circuit and an output signal of the timing detection circuit as input, and conduction of the thyristor circuit. A thyristor drive circuit that outputs a gate signal that controls the voltage of the thyristor circuit, and controls the conduction angle of the thyristor circuit to continuously control the reactive power flowing in the main circuit to perform constant voltage control of the distribution line or the transmission line. Static var compensator. 4. A first reactor connected to a distribution line or a transmission line, a series circuit of a second reactor and a capacitor, and one connected to a connection point of the first reactor and the second reactor. Alternatively, a main circuit composed of a thyristor circuit composed of an anti-parallel circuit of a plurality of serial thyristors, and a PT attached to the distribution line or transmission line.
An effective value detection circuit that detects an effective value of the PT output; a timing detection circuit that receives the output of the PT and detects a zero-cross timing of the interphase voltage of the distribution line or the transmission line; A CT installed between the reactor and the distribution line or the transmission line to detect the input current of the main circuit, and a reactive power detection circuit to detect the reactive power flowing into the main circuit by using the output signals of the PT and the CT as inputs. And an error signal between the output signal of the voltage effective value detection circuit and a preset voltage command value as input
Arithmetic circuit, a second arithmetic circuit that receives an error signal between the output signal of the first arithmetic circuit and the output signal of the reactive power detection circuit, the output signal of the second arithmetic circuit, and the timing. A thyristor drive circuit that receives the output signal of the detection circuit as an input and outputs a gate signal that controls the conduction angle of the thyristor circuit, a power supply rise detection circuit, and an output signal of the power supply rise detection circuit as an input and a certain time after the power supply rises. For inputting the output of the timer, the input signal of the thyristor drive circuit, and the output signal of the reactive power detection circuit as the input, and the reactive power is near 0 Var in the normal operating state after the timer times out. And a storage circuit that stores the input signal of the thyristor drive circuit at the time of, and retains the stored content even when the power is off. The circuit receives the output signal of the storage device and the output signal of the timer in addition to the error signal between the output signal of the first arithmetic circuit and the output signal of the reactive power detection circuit, and after the power supply rises, the circuit The thyristor drive circuit is configured to output an output signal in which the reactive power stored in the memory circuit is close to 0 Var until the timer times out, and to perform normal arithmetic processing after the timer times up. A static var compensator for controlling a conduction angle of the thyristor circuit and continuously controlling reactive power flowing in the main circuit to perform constant voltage control of the distribution line or the transmission line. 5. A first reactor connected to a distribution line or a transmission line, a series circuit of a second reactor and a capacitor, and one connected to a connection point of the first reactor and the second reactor. Alternatively, a main circuit composed of a thyristor circuit composed of an anti-parallel circuit of a plurality of serial thyristors, and a PT attached to the distribution line or transmission line.
An effective value detection circuit that detects an effective value of the PT output; a timing detection circuit that receives the output of the PT and detects a zero-cross timing of the interphase voltage of the distribution line or the transmission line; A first CT that is installed between the reactor and the distribution line or the transmission line and detects an input current of the main circuit, and a reactive power that flows into the main circuit by using the output signals of the PT and the first CT as input. The reactive power detection circuit for detecting, and the C in the distribution line or the transmission line.
The second CT attached to the load side of T and the P
An active power change amount detection circuit which receives an output signal of T and an output signal of the second CT and detects a change amount of active power flowing in the distribution line or the power transmission line, an output signal of the PT and the second A reactive power change detection circuit that receives a CT output signal as an input and detects a change in the reactive power that flows in the distribution line or the transmission line, and a line constant memory that stores the line constant of the distribution line or the transmission line up to the local point A circuit, a third arithmetic circuit having the active power change detection circuit, the reactive power change detection circuit, and the line constant storage circuit as inputs, and an output signal of the voltage effective value detection circuit, which are set in advance. A first arithmetic circuit that receives an error signal with respect to a voltage command value, an adder circuit that receives the output signal of the third arithmetic circuit and an output signal of the first arithmetic circuit, and an output of the adder circuit. Signal and the above A second arithmetic circuit that receives an error signal from the output signal of the power detection circuit and an output signal of the second arithmetic circuit and an output signal of the timing detection circuit that control the conduction angle of the thyristor circuit. A thyristor drive circuit for outputting a gate signal, which controls the conduction angle of the thyristor circuit to continuously control the reactive power flowing in the main circuit to perform constant voltage control of the distribution line or the transmission line. Type reactive power compensator.