JP3328039B2 - Static var compensator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a static type in which a thyristor circuit is controlled in a power system to which a load causing a variation in reactive power is connected to compensate for the variation in reactive power caused by the operation of the load. 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, a voltage at a connection point of the load fluctuates according to a reactive current flowing through the load.
It may adversely affect other power consumers connected to the same power system. A static var compensator is provided to suppress such voltage fluctuations.

FIG. 6 shows a connection diagram of a conventional static var compensator. Reference numeral 1 denotes a first reactor, 2 denotes a second reactor, 3 denotes a capacitor, 4 denotes a thyristor circuit having one or more anti-parallel thyristors whose conduction angle is adjustable, and 5 denotes 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) for detecting the voltage of the distribution line or transmission line 6, and 8 is full-wave rectification A timing detection circuit 9 for detecting a zero-cross timing of the inter-phase voltage of the distribution line or the transmission line 6;
Is an arithmetic circuit.

Next, the operation of the main circuit 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, the terminal voltage VR1 of the first reactor 1 and the Since the terminal voltage VR2 of the reactor 2 becomes minimum, the leading reactive power becomes maximum.
On the other hand, the thyristor driving circuit 5 causes the thyristor circuit 4
Is conducted at a certain control angle in the direction of time advance from the zero-cross point of each inter-phase voltage, 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 decreases, and the lag reactive power by the first reactor 1 increases. Also, due to the conduction of the thyristor circuit 4, the electric charge of the capacitor 3 becomes the second
Is inverted through the reactor 2 and the thyristor circuit 4, and this inverted charge is turned off after the thyristor circuit 4 is turned off.
It flows into the distribution line or the transmission line 6 as a lagging current, and generates lagged reactive power. If the delay control angle of the thyristor circuit 4 is further advanced, the advance reactive power decreases as a whole, and the delay reactive power increases. Thus, the thyristor circuit 4
Can be continuously controlled from the leading reactive power to the lag reactive power.

Next, the operation of controlling the inter-phase voltage of a distribution line or a transmission line by controlling such a main circuit will be described. The phase voltage of the distribution line or transmission line 6 is PT7
And converted by the full-wave rectifier circuit 8 into a feedback signal of an inter-phase voltage. The error signal between the feedback signal of the inter-phase 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 driving circuit 5, for example, when the inter-phase voltage is higher than the voltage command value, the thyristor firing timing is shifted forward from the zero-cross point of the inter-phase voltage according to the firing timing command value of the arithmetic circuit 10, and the static reactive power compensation. Control is performed so that the operating point of the device shifts to the delay side, and feedback control is performed so that the inter-phase voltage decreases and matches the voltage command value. Conversely, if the inter-phase voltage is lower, the thyristor firing timing is controlled to approach the zero-cross point of the inter-phase voltage so that the operating point of the static var compensator shifts to the leading side. Feedback control is performed so as to match the command value.

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

[0007]

The conventional static var compensator has the above-described configuration. First, the interphase voltage of the distribution line or the transmission line is full-wave rectified as a feedback signal. When the inter-phase voltage includes a distorted wave, an error occurs in the constant voltage control.

Second, since the conventional control circuit has only a feedback loop of the inter-phase voltage, a large thyristor current flows when the inter-phase voltage greatly fluctuates and the voltage error signal becomes large, which may destroy the thyristor. There is.

Third, in the prior art example, there is a possibility that the control circuit has run out immediately after the power is turned on. In this case, the static var compensator rises with a lead or delay of 100%. In this case, there is a possibility that the inter-phase voltage of the distribution line or the transmission line abnormally rises or falls.

Fourth, since the conventional example is based on voltage feedback control, there is a limit to the responsiveness to a sudden change in the inter-phase 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. I do.

[0011]

Means for Solving the Problems To solve the above problems,
The static var compensator of the present invention
Multiple reactors and multiple capacitors connected to the transmission line
Thyristor consisting of an anti-parallel circuit consisting of
And a circuit for controlling the conduction angle of the thyristor.
A main circuit that generates reactive power delayed from advance by
And a transformer attached to the distribution line or the transmission line
(Hereinafter referred to as PT) and detecting the effective value of the output of the PT
An effective value detection circuit, and an output of the PT as an input.
Timing of zero crossing of phase voltage of distribution line or transmission line
A timing detection circuit for detecting the first reaction;
Installed between the distribution line and the transmission line.
A current transformer (hereinafter referred to as CT) for detecting an input current of a road;
The output signals of the PT and the CT are input to the main circuit.
A reactive power detection circuit for detecting the flowing reactive power;
The output signal of the voltage effective value detection circuit and the preset
A first arithmetic circuit that receives an error signal from a voltage command value as an input
And the output signal of the first arithmetic circuit is defined as a reactive power command value.
Limiter for inputting and outputting the limiter and the output of the limiter.
An error signal from the output signal of the active power detection circuit is input.
2 arithmetic circuit, an output signal of the second arithmetic circuit,
The output signal of the timing detection circuit is input to the thyristor
Thyristor that outputs a gate signal that controls the conduction angle of the
A reactive power command value by the limiter.
Prevents overcurrent to the main circuit by setting upper and lower limits
Control the conduction angle of the thyristor circuit
The distribution line is controlled by continuously controlling the reactive power flowing through the main circuit.
Or, it is designed to control the transmission line voltage constant.
You .

Also, a static var compensator according to the present invention.
Is a series of reactors connected to distribution or transmission lines.
And an anti-parallel circuit of multiple capacitors and multiple thyristors
And a thyristor circuit.
Generates reactive power from advance to delay by controlling the passing angle
Main circuit to be generated and attached to the distribution line or transmission line
The detected PT and an effective value for detecting an effective value of the output of the PT.
Value detection circuit and the output of the PT
Or the timing of the zero crossing of the transmission line phase-to-phase voltage
Timing detection circuit and the thyristor circuit
A CT attached to the
A thyristor for detecting a current value flowing through the thyristor circuit;
Output current of the star current detection circuit and the effective voltage value detection circuit.
Signal between the signal and the preset voltage command value.
A first arithmetic circuit as a force, and an output of the first arithmetic circuit
Limiter that inputs a signal as a thyristor current command value
And the output signal of the limiter and the thyristor current detection
A second operation circuit which receives an error signal from the output signal of the circuit as an input
Path, output signal of the second arithmetic circuit, and the timing
The output signal of the detection circuit is input and the
Thyristor drive circuit that outputs a gate signal to control the through angle
And a limiter for the thyristor current command value by the limiter.
Setting the lower limit prevents overcurrent to the main circuit.
To control the conduction angle of the thyristor circuit,
The reactive power flowing through the main circuit is continuously controlled to
Or constant voltage control of the transmission line.
You .

Further , the static var compensator according to the present invention.
Is a series of reactors connected to distribution or transmission lines.
And an anti-parallel circuit of multiple capacitors and multiple thyristors
And a thyristor circuit.
Generates reactive power from advance to delay by controlling the passing angle
Main circuit to be generated and attached to the distribution line or transmission line
The detected PT and an effective value for detecting an effective value of the output of the PT.
Value detection circuit and the output of the PT
Or the timing of the zero crossing of the transmission line phase-to-phase voltage
Timing detection circuit, and the first reactor
Installed between the distribution line or the transmission line and the input of the main circuit
CT for detecting current, the PT and the output signal of the CT
To detect the reactive power flowing into the main circuit
Active power detection circuit and output signal of the effective voltage value detection circuit
And the error signal between the preset voltage command value and
A first arithmetic circuit, and an output signal of the first arithmetic circuit.
Signal and the output signal of the reactive power detection circuit.
A second arithmetic circuit as a force, and an output of the second arithmetic circuit
Signal and the output signal of the timing detection circuit
Outputs gate signal to control conduction angle of thyristor circuit
Thyristor drive circuit, power supply rise detection circuit,
The output signal of the power supply rise detection circuit is input and the power supply
Timer that counts a certain time only once after rising
And an output of the timer and an input of the thyristor drive circuit
Signal and the output signal of the reactive power detection circuit
In the normal operation state after the timer expires,
The input signal of the thyristor drive circuit when the voltage is near 0 Var
No. to retain the stored contents even when the power is turned off.
Storage circuit, wherein the second arithmetic circuit is configured to perform the first operation.
And the output signal of the reactive power detection circuit
The output signal of the storage device and the
The output signal of the
Until the time of the imager expires, the contents stored in the storage circuit are used.
Output an output signal in which the reactive power is close to 0Var.
After the timer expires, perform normal arithmetic processing.
To prevent transient abnormal voltage at power recovery from power outage
The thyristor drive circuit.
Controls the conduction angle of the lister circuit and disables the flow through the main circuit.
The power is continuously controlled to reduce the voltage of the distribution line or transmission line.
The constant control is performed .

Further , the static var compensator according to the present invention.
Is a series of reactors connected to distribution or transmission lines.
And an anti-parallel circuit of multiple capacitors and multiple thyristors
And a thyristor circuit.
Generates reactive power from advance to delay by controlling the passing angle
Main circuit to be generated and attached to the distribution line or transmission line
The detected PT and an effective value for detecting an effective value of the output of the PT.
Value detection circuit and the output of the PT
Or the timing of the zero crossing of the transmission line phase-to-phase voltage
Timing detection circuit, and the first reactor
Installed between the distribution line or the transmission line and the input of the main circuit
A first CT for detecting a current, the PT and the first C
Reactive power flowing into the main circuit with the output signal of T as input
A reactive power detection circuit for detecting
A second CT attached to the wire on the load side of the CT
And the output signal of the PT and the output signal of the second CT
Changes in active power flowing through the distribution line or transmission line as input
An active power change detecting circuit for detecting a change in
An output signal and an output signal of the second CT,
Detects changes in reactive power flowing through wires or transmission lines
Reactive power change detection circuit and the distribution line to the local point
Or a line constant storage circuit for storing line constants of transmission lines,
The active power change detection circuit and the reactive power change detection
Circuit and an output signal of the line constant storage circuit as an input.
3 and an output signal of the effective voltage value detection circuit.
Input an error signal with a preset voltage command value
A first arithmetic circuit, and an output signal of the third arithmetic circuit
And an adder circuit that receives an output signal of the first arithmetic circuit as an input
Output from the addition circuit as a reactive power command signal.
An error signal between the output signal and the output signal of the reactive power detection circuit.
Arithmetic circuit having a signal as input, and the second arithmetic circuit
Input signal and the output signal of the timing detection circuit
And a gate signal for controlling the conduction angle of the thyristor circuit
A thyristor drive circuit that outputs
The reactive power command signal output from the third arithmetic circuit
And the output signal of the first arithmetic circuit are added.
To suppress voltage fluctuations at high speed.
The reactive current flowing through the main circuit by controlling the conduction angle of the
Control the power continuously to keep the voltage of the distribution line or transmission line constant
The control is performed .

[0015]

[0016]

According to the present invention, the following functions are provided by the above-described configuration. First, constant voltage control of distribution lines or transmission lines can be accurately performed irrespective of distortion of inter-phase voltage. Second, a thyristor current or reactive power feedback loop is provided, and by setting an upper limit value for the current of the main circuit, thyristor destruction can be prevented. Third, 0V when power is restored after a power failure
The static reactive power compensator can be started from the operating point of ar to prevent a transient abnormal voltage. Fourth, it is possible to generate a reactive power that suppresses a sudden change in voltage of a distribution line or a transmission line, thereby correcting the voltage change at high speed.

[0017]

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. 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 transmission line 6. , At the connection point between the first reactor and the second reactor
Together with the three thyristor circuits 4 connected in a form, they form the main circuit of the static var compensator. Reference numeral 7 denotes a transformer (hereinafter referred to as PT) for detecting a voltage between phases of the distribution line or the transmission line 6.
Reference numeral 11 denotes an effective value detection circuit which receives the PT7 output and obtains an effective value output. An arithmetic circuit 10 receives an error signal between a voltage command value and an effective value output of an effective value detection circuit and outputs a thyristor drive command signal, and 5 receives a thyristor drive command signal as input and is detected by a timing detection circuit 9. This is a thyristor drive circuit that outputs a firing signal of the thyristor circuit 4 with reference to the zero-cross point of each inter-phase voltage. When the operating point of the static var compensator is shifted to the lag side by the thyristor drive circuit 5, the firing signal of the thyristor circuit 4 is shifted forward in time with the zero cross point of each inter-phase voltage as a starting point, When moving to the leading side, return to the zero cross point of the inter-phase voltage.

Meanwhile, there is a long distribution line or transmission line 6 between the substation or the 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 leading side, the voltage at the installation point increases, and conversely, when it operates on the lag side, the voltage at the installation point decreases.

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 inter-phase voltage of the distribution line or the transmission line becomes zero, the distribution line at the installation point or This allows constant control of the inter-phase voltage of the transmission line.

Heretofore, the feedback voltage has been conventionally detected by full-wave rectification. However, when a distorted wave is superimposed on the inter-phase 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 value voltage.

In this embodiment, an example in which the signal processing is performed by an electronic circuit is shown in a block diagram. However, the signal processing of the feedback control can be realized by software processing of a microcomputer.

Next, a second embodiment of the static var compensator according to the present invention will be described with reference to FIG. The main circuit is the same as in the first embodiment, and a description thereof will be omitted. However, a current transformer (hereinafter referred to as CT) 16 for detecting the input current of the static var compensator is installed at a 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 from the output signal of CT and the output signal of PT7. On the other hand, an error signal between the voltage command value and the feedback value of the inter-phase voltage of the distribution line or the transmission line 6 is calculated by the first arithmetic circuit 1.
3 to obtain a reactive power command value of the static var compensator. The reactive power command value is set to the upper and lower limits through a limiter 14, compared with the reactive power feedback signal from the reactive power detection circuit 15, and the error signal is input to the second arithmetic circuit 12, and the thyristor is output by the output signal. The firing angle of the thyristor circuit 4 is controlled via the drive circuit 5.
Since the upper and lower limit values are set to the reactive power command value by the limiter 14, the input current and the thyristor current of the static type reactive power compensator can be set to the upper and lower limit values as a result. 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 in the first embodiment.

In this embodiment, an example in which the signal processing is performed by an electronic circuit is shown in a block diagram. However, the signal processing of the feedback control can be realized by software processing of a microcomputer.

Next, a third embodiment of the static var compensator according to 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 installation location of the CT 17 is installed in series with the thyristor circuit 4,
The thyristor current is detected by the thyristor current detection circuit 17 and the thyristor current detection circuit 18 and is used as a thyristor current feedback value. On the other hand, an error signal between the voltage command value and the feedback value of the inter-phase voltage of the distribution line or the transmission line 6 is input to the first arithmetic circuit 13 to obtain a thyristor current command value of the static var compensator. The upper and lower limit values of the thyristor current command value are set through the limiter 14, and an error signal which is 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 is used as the thyristor drive circuit. The control of the firing angle of the thyristor circuit 4 is carried out via 5. Since the upper and lower limits of the thyristor command value are set by the limiter 14, as a result, the upper and lower limits of the thyristor current of the static var compensator can be set, and indirectly the overcurrent of the main circuit components can be set. 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 in the first embodiment.

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

Next, a fourth embodiment of the static var compensator according to 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 which receives the output signal and the output signal of the second arithmetic circuit 12 as inputs 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 elapsed since the power-on. That is, whether the control circuit of the static var compensator is in the transient state immediately after the power is turned on,
It is determined whether it is in a steady state, and 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 employs a non-volatile memory or performs a 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 restoration of the power supply is in a transient state, the operating point of the static var compensator previously stored in the storage circuit 19 becomes 0.
A command value to the thyristor drive circuit that becomes Var is output through the second arithmetic circuit 12 so that the static var compensator performs 0 Var operation without swinging. Thereafter, when the control circuit of the static var compensator enters a steady state, the control is switched to the normal feedback control. 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, and therefore will not be described.

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

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

Qs = ΔQ + ΔP × (R / L) (1) Therefore, the resistance and the inductance of the distribution line or the transmission line 6 from the substation or the power station to the site point are stored and stored in the line constant storage circuit 25. The third arithmetic circuit 26 calculates the equation (1) to calculate a reactive power command value for compensating for a variation in the inter-phase voltage at the installation point of the static var compensator due to a sudden change in the load. And the first arithmetic circuit 1
By adding the reactive power command value from No. 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,
Open-loop control is performed by calculating the output of the static var compensator required to compensate for voltage fluctuations in consideration of the constants of the distribution line or transmission line, so voltage fluctuations can be suppressed more quickly. Can be. 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, and therefore will not be described.

In this embodiment, the signal processing is shown in the block diagram on the assumption that the signal processing is performed by an electronic circuit. However, the signal processing of each control may be realized by software processing of a 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 a Y-connection, but this reactor and the capacitor are connected in a Δ-connection. It does not matter. Although the present embodiment has been described with reference to a three-phase circuit, it goes without saying that the present embodiment can be applied to a single-phase circuit.

[0032]

As is clear from the above description, according to the present invention, the following effects can be obtained. First,
First, constant voltage control of distribution lines or transmission lines can be accurately performed irrespective of distortion of inter-phase voltage. Therefore, it is very effective for voltage stabilization in a situation where harmonics of distribution lines or transmission lines increase and voltage distortion cannot be ignored as in today. Second, a thyristor current or a reactive power feedback loop is provided, and the thyristor can be prevented from being broken by setting an upper limit value for the current of the main circuit. As a result, high reliability required as equipment of the distribution system or the transmission system can be secured. Third, 0V when power is restored after a power failure
The static reactive power compensator can be started from the operating point of ar to prevent a transient abnormal voltage. Fourth, it is possible to generate a reactive power that suppresses a sudden change in voltage of a distribution line or a transmission line, thereby correcting the voltage change at high speed.

[Brief description of the 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]

 DESCRIPTION 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 Operation circuit 11 Effective value detection circuit 12 Second Arithmetic circuit 13 first arithmetic circuit 14 limiter 15 reactive power detection circuit 16, 17 current transformer 18 thyristor current detection circuit 19 storage circuit 20 timer 21 power supply rise detection circuit 22 second current transformer 23 active power change detection Circuit 24 Reactive power change detection circuit 25 Line constant storage circuit 26 Third operation circuit 27 Addition circuit

Claims (4)

(57) [Claims] 1. A thyristor circuit comprising a plurality of reactors connected to a distribution line or a transmission line, a plurality of capacitors, and an anti-parallel circuit of a plurality of thyristors, and controlling a conduction angle of the thyristor to delay from advancing. A transformer (hereinafter referred to as PT) attached to the distribution line or the transmission line, an effective value detection circuit for detecting an effective value of the output of the PT, and an output of the PT. And a timing detection circuit for detecting a zero-cross timing of the inter-phase voltage of the distribution line or the transmission line, and detecting an input current of the main circuit provided between the first reactor and the distribution line or the transmission line. A current transformer (hereinafter, referred to as CT); and a reactive power detection circuit that receives output signals of the PT and the CT and detects reactive power flowing into the main circuit. , <Br first arithmetic circuit which receives the error signal with a preset voltage command value and the output signal of the voltage effective value detection circuit, an output signal of said first arithmetic circuit as reactive power command value An input limiter, a second arithmetic circuit that receives an error signal between an output of the limiter and an output signal of the reactive power detection circuit, and an output signal of the second arithmetic circuit and the timing detection circuit. A thyristor driving circuit that receives an output signal and outputs a gate signal that controls a conduction angle of the thyristor circuit, and sets the upper and lower limits of the reactive power command value with the limiter.
In order to prevent overcurrent to the main circuit, to control 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 transmission line. Static var compensator. 2. A thyristor circuit comprising a plurality of reactors connected to a distribution line or a transmission line, a plurality of capacitors, and an anti-parallel circuit of a plurality of thyristors, and controlling a conduction angle of the thyristor to delay from advancing. A main circuit that generates reactive power, a PT attached to the distribution line or the transmission line, an effective value detection circuit that detects an effective value of an output of the PT, A timing detection circuit for detecting a zero-cross timing of an inter-phase voltage of a transmission line; a CT mounted in series with the thyristor circuit; and a thyristor current detection for detecting a current value flowing through the thyristor circuit with an output signal of the CT as an input. A circuit, and an input of an error signal between an output signal of the voltage effective value detection circuit and a preset voltage command value. A first arithmetic circuit, and an output signal of the first arithmetic circuit, a thyristor current command value
A second arithmetic circuit that receives as input an error signal between the output signal of the limiter and the output signal of the thyristor current detection circuit; and an output signal of the second arithmetic circuit and the timing detection circuit. A thyristor drive circuit that receives an output signal and outputs a gate signal that controls the conduction angle of the thyristor circuit, and sets the upper and lower limits of the thyristor current command value with the limiter
By doing so, the overcurrent to the main circuit is prevented , the conduction angle of the thyristor circuit is controlled, the reactive power flowing through the main circuit is continuously controlled, and the voltage control of the distribution line or the transmission line is performed. Static power compensator. 3. A thyristor circuit composed of a plurality of reactors connected to a distribution line or a transmission line, a plurality of capacitors, and an anti-parallel circuit of a plurality of thyristors, and controlling a conduction angle of the thyristor to delay from advancing. A main circuit that generates reactive power, a PT attached to the distribution line or the transmission line, an effective value detection circuit that detects an effective value of an output of the PT, A timing detection circuit for detecting a zero-cross timing of an inter-phase voltage of a transmission line; a CT installed between the first reactor and the distribution line or the transmission line to detect an input current of the main circuit; A reactive power detection circuit that receives a CT output signal as input and detects reactive power flowing into the main circuit; and an output signal of the effective voltage value detection circuit. A first arithmetic circuit that receives an error signal from a preset voltage command value as an input, and an error signal between an output signal of the first arithmetic circuit and an output signal of the reactive power detection circuit as an input A second arithmetic circuit, a thyristor drive circuit that receives an output signal of the second arithmetic circuit and an output signal of the timing detection circuit, and outputs a gate signal that controls a conduction angle of the thyristor circuit; A timer that counts a given time after power-on only once with an output signal of the power-on detection circuit as an input, an output of the timer, an input signal of the thyristor drive circuit, and an output signal of the reactive power detection circuit. And the reactive power is 0 V in the normal operation state after the timer expires.
a storage circuit that stores an input signal of the thyristor drive circuit when the signal is in the vicinity of ar and retains stored contents even when the power is turned off. The second arithmetic circuit includes an output signal of the first arithmetic circuit and an output signal of the first arithmetic circuit. In addition to the error signal from the output signal of the reactive power detection circuit, the output signal of the storage device and the output signal of the timer are input, and the contents of the storage circuit are stored after power-on until the timer times out. Some reactive power is 0V
An output signal that is close to ar is output, and normal operation processing is performed after the timer expires, thereby causing a power outage.
The thyristor drive circuit controls the conduction angle of the thyristor circuit, and continuously controls the reactive power flowing through the main circuit, so that the distribution line or the transmission line is prevented. A static var compensator that performs constant voltage control. 4. A thyristor circuit comprising a plurality of reactors connected to a distribution line or a transmission line, a plurality of capacitors, and a plurality of thyristors in an anti-parallel circuit, and controlling a conduction angle of the thyristor to delay from advancing. A main circuit that generates reactive power, a PT attached to the distribution line or the transmission line, an effective value detection circuit that detects an effective value of an output of the PT, A timing detection circuit for detecting a zero-cross timing of an inter-phase voltage of a transmission line; a first CT installed between the first reactor and the distribution line or the transmission line for detecting an input current of the main circuit.
And a reactive power detection circuit that receives the PT and the output signal of the first CT as input and detects a reactive power flowing into the main circuit; and a reactive power detection circuit attached to the distribution line or the transmission line closer to the load than the CT. 2, an active power change detection circuit that receives an output signal of the PT and an output signal of the second CT and detects a change in active power flowing through the distribution line or the transmission line, and an output of the PT. A reactive power change detection circuit that receives a signal and an output signal of the second CT as input and detects a change in reactive power flowing through the distribution line or the transmission line; and a line constant of the distribution line or the transmission line to a local point. A third constant circuit that receives an output signal of the active power change detection circuit, the reactive power change detection circuit, and the line constant storage circuit ; and a voltage effective value detection circuit. A first arithmetic circuit for inputting an error signal between a road output signal and a preset voltage command value, and an output signal of the third arithmetic circuit and an output signal of the first arithmetic circuit for input An addition circuit, a second arithmetic circuit that receives an error signal between an output signal output from the addition circuit as a reactive power command signal and an output signal of the reactive power detection circuit, and an output signal of the second arithmetic circuit A thyristor drive circuit that receives an output signal of the timing detection circuit as an input and outputs a gate signal that controls a conduction angle of the thyristor circuit, and the reactive power command signal output from the addition circuit is
3 and the output signal of the first arithmetic circuit
To quickly suppress voltage fluctuations by adding
And a static var compensator configured to control the conduction angle of the thyristor circuit and continuously control the reactive power flowing through the main circuit to perform constant voltage control of the distribution line or the transmission line.