JPH0235326B2 - SEISHIGATAJIDODENATSUCHOSEISOCHI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a static automatic voltage regulator that adjusts line voltage by switching taps by turning on and off thyristor switches connected to each tap of a regulating transformer.

Generally, a plurality of power distribution systems come out of a substation, and each power distribution system is connected downstream to an adjacent power distribution system via a sectional switch for interconnection. Normally, this interconnection sectional switch is open. Now, there are two distribution lines L ₁ and L ₂ , an automatic voltage regulator is installed on each distribution line (assuming that it is installed in the midstream part of the distribution line), and the downstream parts of both distribution lines are It is assumed that the system is interconnected via a sectional switch for interconnection. Each distribution line has a large number of loads distributed upstream, midstream, and downstream. Therefore, there is a load on both the primary and secondary sides of the regulating transformer. Normally, the regulator transformer has a step-up tap selected to prevent downstream voltage drops.

By the way, if the upstream part of distribution line L ₂ is cut off due to construction, etc., in order to avoid a power outage, close the interconnection section switch and connect the distribution line L ₁ through the interconnection section switch. Supplying power to the load on the wire L ₂ is carried out.

In this case, the voltage regulator of distribution line L ₂ is
The next side becomes the primary side, and the original primary side becomes the secondary side. That is, the regulating transformer is reverse excited and a reverse flow of power occurs.

In this case, if the regulating transformer had been performing a step-up operation, this reverse excitation (by the reverse flow of power) causes it to perform a step-down operation.

As a result, the voltage on the primary side of the main body of the regulating transformer (which becomes the secondary side when power flows backward) is lowered, which has a negative effect on the load connected here.

Conventionally, automatic voltage regulators using the above-mentioned mechanical switching devices are equipped with a control device that detects when a reverse current occurs and fixes it to the tap that is currently energized. be. In this case, a power direction relay is used because it is necessary to detect the direction of power in order to detect reverse current. However, even with such control, it is not possible to prevent the voltage of the load from running out due to reverse excitation of the regulating transformer. In addition, when the regulating transformer is reverse excited while energized by the step-up tap and fixed at that tap, and then the reverse excitation is removed, the voltage of the load on the secondary side of the regulating transformer is suddenly energized by the step-up tap. may become excessive. Therefore, even if such control is performed to fix the current-carrying tap during reverse excitation, the adverse effect on the load cannot be eliminated.

SUMMARY OF THE INVENTION An object of the present invention is to provide a static automatic voltage regulator that does not adversely affect the load connected to the primary line of the regulating transformer when reverse power flows through the regulating transformer. .

The present invention relates to a static automatic voltage regulator equipped with a regulating transformer connected to a line and a thyristor switch for tap selection connected to each tap of the regulating transformer. A power directional relay 601 that detects reverse power flowing back from the secondary side to the regulating transformer 11, and a power direction relay 601 inserted in the circuit on the power supply side, and a power direction relay 601 that detects reverse power flowing back from the secondary side to the regulating transformer 11, A ignition signal is continuously given to the thyristor switch S ₁ connected to the tap (hereinafter referred to as a "pass-through tap") which is directly connected to the tap and the voltage is not converted (hereinafter referred to as a "pass-through tap") t ₁ to turn on the mustard switch 5 and turn on the power direction relay 601. When reverse power is detected, only the thyristor switch _S1 of the tap selection thyristor switches connected to tap t1, whose primary and secondary sides are directly connected and whose voltage is not converted, is made conductive and the primary and secondary sides are connected. Tap t ₁ that is directly connected to the next side and does not convert voltage
The present invention is characterized in that it is provided with a control device 6 that performs a control operation to fix the tap t1 to t1, and when the reverse power disappears, releases the control operation to fix the tap t1 to a tap t1 where the primary side and the secondary side are directly connected and no voltage conversion is performed. do. With this configuration, when the regulating transformer is reverse excited, it is fixed to the through tap, so there is no shortage of voltage applied to the load connected to the line on the primary side of the regulating transformer. In addition, since the load is still energized through the through tap even after reverse excitation is eliminated, there is no risk of inconveniences such as sudden energization at the step-up tap and excessive voltage being applied to the load on the secondary side of the regulating transformer. do not have.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The static automatic voltage regulator of the present invention will be described in detail below with reference to the illustrated embodiments.

Figure 1 shows the overall configuration of the present invention using a single line diagram together with the power distribution system. In the figure, 1 is a substation, 2 is a load, and 3 is connected to a line 4 that connects the substation and the load. The direct switching type static automatic voltage regulator 5 is a circuit breaker inserted in the circuit on the power supply side of the voltage regulator 3. Further, 6 is a control device that controls the voltage regulator 3 and the shield breaker 5, and the output of the current transformer CT for overcurrent detection provided in the shield breaker is input to this control device, and the control device The power source of the device 6 is supplied from a line on the power side side of the disconnector 5 via a control power transformer 8, a control power cable 9, and a control power switch 10.
In FIG. 1, the thick line portion indicates the high voltage section.

In this embodiment, the static automatic voltage regulator 3 is
As shown in the figure, a regulating transformer 11 consisting of an autotransformer having multistage taps t ₁ to ^{t 6} (the number of taps is arbitrary)
and thyristor switches S 1 to _{S 6} each having one end connected to the taps t ₁ to _{t 6} of the regulation transformer ₁₁ , and a terminal 12r connected to one end of the transparent tap t ₁ side of the regulation transformer 11 and the regulation transformer. Terminals 12'r connected to the other end of the device 11 are respectively connected to lines on the secondary side. The other ends of the thyristors S ₁ to S ₆ are connected to one end of the reactors L ₁ to _{L 6} , respectively, and the other ends of the reactors L ₁ to _{L 6} are commonly connected and input via the main contact 51A of the breaker 5. It is connected to terminal 12S. Further, the output terminal 1 of the regulating transformer 11
The end connected to 2'r is the main contact 51 of the disconnector 5.
It is connected to the input terminal 12'S via B, and the line on the primary side (substation side) is connected to the input terminals 12S, 12'S.

Reactor L ₁ ~ _{L 6} and thyristor switch S ₁ ~
An auxiliary current transformer is installed on each line connecting _S6 .
CT ₁ to CT ₆ are provided, and these auxiliary current transformers are adapted to detect the current flowing through the taps t ₁ to _{t 6} .

The control device 6 performs the original control operation of an automatic voltage regulator, controlling the on/off of thyristor switches S ₁ to S ₆ according to the output of the voltage regulating relay in order to switch the taps of the regulating transformer 11 so as to maintain the line voltage at a predetermined value. In addition, when the regulating transformer is reversely excited, the thyristor switch is configured to carry out a control operation in which only the through-tap thyristor switch is brought into conduction.

As shown in Fig. 3, each thyristor switch has two thyristors SCR ₁ and SCR ₂ connected in antiparallel, and a surge absorption capacitor C ₀ and a resistor R ₀ connected in parallel to these thyristors.
It consists of a series circuit connected to a semiconductor arrester _LA1 , and depending on the direction of the line current, one of the thyristors becomes conductive to select a tap.

An example of the configuration of the control device 6 is shown in FIG. In the figure, 601 has a logical value of "1" when reverse power flows into the regulating transformer 11 from the secondary side.
This is a power direction relay that outputs a reverse power adjustment signal _e1 , and _this power _direction relay operates as shown in FIG. A rectangular waveform detection signal _e1 is output. Reference numeral 602 denotes a reverse power extinction detection circuit which receives the output of the power directional relay 601 as an input and detects the disappearance of reverse power.This detection circuit is composed of, for example, a mono-multivibrator, and as shown in FIG. At the falling edge of the output signal e1 of 601, a pulse-like reverse power extinction detection signal with a constant width is generated.
Output e ₂ ′. This detection signal e ₂ ' is sent to the delay circuit 60
3, and the delay circuit 603 outputs a reverse power disappearance detection signal _e2 at time _T4 , which is delayed by a certain period of time from time _T3 when the reverse power disappears.

In Fig. 4, A ₀₀ , A ₁₁ to A ₁₆ , A ₂₁ to _{A 26} and
A ₃₀ to _{A 36} are 2-input AND circuits, OR ₀ to OR ₆ are OR circuits, FF ₀ to _{FF 6} are flip-flop circuits, A _n1
〜A _n6 is an amplifier made of a transistor, and P ₁ to _{P 6} are made of a DC power supply E and a pulse transformer P _t . When a signal of “1” is input to each of the amplifiers A _n1 to _{A n6} , a pulse-like The pulse output circuit outputs the ignition signals e _g1 and e _g2 simultaneously, and _F1 to _F6 are filter circuits for direct current conversion and noise removal consisting of a full-wave rectifier _Rec3 , a resistor _R2, and a capacitor _C2 . , these constitute a circuit that controls on/off of the thyristor switches _S1 to _S6 . More specifically, the AND circuits A ₀₀ , A ₁₁ to _{A 12} and A ₂₁
A signal e ₃ consisting of a rectangular wave of about 3 kHz continuously obtained from the signal source circuit 606 is input to one input terminal of each of ~A ₂₆ , and the output of the AND circuit A ₀₀ is sent to the amplifier through the OR circuit OR ₀ . A is input to _n1 . The output of the flip-flop circuit FF ₀ is input to the other input terminal of the AND circuit A ₀₀ ,
A reverse power detection signal e ₁ obtained from the power direction relay 601 is input to the set terminal of FF ₀ . Therefore, when the reverse power detection signal _e1 is generated and the flip-flop circuit _FF0 is set, the AND circuit _A00
outputs a signal of “1” and this signal is the OR circuit.
It is input to the amplifier A _n1 through OR ₀ , thereby outputting the ignition signals e _g1 and e _g2 from the pulse output circuit P ₁ . These signals are converted into direct current through a filter circuit _F1 and then sent to thyristors _SCR1 and _SCR2 of a thyristor switch _S1 connected to a transparent tap _T1 .
are supplied to each gate. When the circuit breaker 5 is turned on in this state, the thyristors SCR ₁ and SCR ₂ are alternately made conductive during the positive and negative half cycles of the line voltage, thereby connecting the primary side line to the tap t ₁ .

The outputs v1 to _v6 of the tap switching command signal generation circuit controlled by the voltage regulating relay 607 are input to the other input terminals of the AND circuits _{A11 to A16} , respectively. Tap switching command signal generation circuit 608
For example, the reversible binary counter 608a and the decoder 6
08b, and outputs any one of signals v ₁ to v ₆ instructing selection of taps t ₁ to t ₆ , respectively, in response to a signal from voltage adjustment relay 607.
The outputs of AND circuits A ₁₁ to _{A 16} are input to the set terminals of flip-flop circuits FF ₁ to FF ₆ , respectively.
The outputs of the flip-flop circuits FF ₁ to _{FF 6} are input to one input terminal of the AND circuits A ₂₁ to A ₂₆ . The output of the AND circuit A ₂₁ is input to the amplifier A _n1 via the OR circuit OR ₀ , and
The outputs of A ₂₂ to _{A 26} are input to amplifiers A _n2 to _{A n6} , respectively. The outputs of amplifiers A _n2 to _{A n6} are connected to pulse output circuits P ₂ to _{P 6} and filter circuits ₂ to F ₆ , respectively.
The thyristor switches S ₂ to _{S 6} are supplied to the thyristors to select the taps T ₂ to _{T 6} through. Further, the output of the OR circuit OR ₀ is supplied to one input terminal of the AND circuit A ₃₁ , and the outputs of the AND circuits A ₂₂ to _{A 26} are supplied to one input terminal of the AND circuits A ₃₂ to _{A 36} , respectively. Tap current detection circuits 6 are connected to the other input terminals of AND circuits A ₃₁ to _{A 36} , respectively.
Tap current detection signals u ₁ to _{u 6} obtained from 09 are input. The tap current detection circuit 609 receives a signal obtained by rectifying the outputs of the auxiliary current transformers CT ₁ to _{CT 6} provided for the taps t ₁ to t ₆ , respectively, with a rectifier Rec ₂ and making the voltage constant with a constant voltage diode ZD.
It inputs u ₁ ′ to _{u 6} ′ and outputs tap current detection signals u ₁ to _{u 6} to the output terminals corresponding to taps t ₁ to t ₆ , respectively. When a current flows, the tap current detection circuit 609 outputs a tap current detection signal corresponding to the selected tap. Among these tap current detection signals u ₁ to _{u 6} ,
The signal u ₁ that detects that current has flowed through the transparent tap t ₁ is also supplied to one input terminal of the AND circuit A ₃₀ , and the output of the AND circuit A ₀₀ is supplied to the other input terminal of the AND circuit A ₃₀ . Supplied. Further, the output of the AND circuit ₃₀ is input to the OR circuits _OR2 to _OR6 , and the output of the AND circuit _A31 is input to the OR circuit _OR2 . The output of AND circuit A ₃₂ is an OR circuit
The output of AND _{circuit A 33 is} input to OR circuits OR ₂ and OR ₄ . Furthermore, the output of AND circuit A ₃₄ is sent to OR circuits OR ₃ and OR ₅ ,
The output of AND circuit A ₃₅ is input to OR circuits OR ₄ and OR ₆ , respectively, and the output of AND circuit A ₃₆ is input to OR circuit OR. OR circuit OR ₁ ~ OR ₆
The outputs of each flip-flop circuit FF ₁ ~
Supplied to the reset terminal of FF ₆ , OR circuit OR ₁
~ When signals in the state of "1" are output from OR ₆ , the outputs of flip-flop circuits FF ₁ to _{FF 6} become "0" and the outputs of AND circuits A ₂₁ to A ₂₆ become "0". It's summery. In order to reset the control circuit when the switch 10 shown in FIG. 1 is turned on, a power-on reset circuit 610 is provided.
The reset signal e _r obtained from this circuit is sent to the tap switching command signal generation circuit 60 via the OR circuit OR _x .
It is supplied to the reset terminal of flip-flop circuit _FF0 via the OR circuit _ORy . This reset signal e _r
are also input to one input terminal of OR circuits OR ₁ to OR ₆ , respectively. Further, the reverse power extinction detection signal e ₂ obtained from the delay circuit 603 is input to the reset terminal of the flip-flop circuit FF ₀ via the OR circuit OR _y , and the detection signal e ₂ ' obtained from the reverse power extinction detection circuit 602 is input to the OR circuit. It is supplied to the reset terminal of the tap switching command signal generation circuit 608 via _ORx . Furthermore, the AND circuit A ₀₀ , A ₁₁ to _{A 16} …
The output of the control power transformer 8 is inputted via the switch 10 to operate each part of the control circuit such as A ₃₁ to _{A 36} , OR circuits OR ₀ to OR ₆ , and flip-flop circuits FF ₀ to _{FF 6} . It is provided by a constant voltage power supply circuit.

Although not shown in FIG. 4, when an overcurrent is detected, the main contacts 51A and 51 of the breaker 5
A circuit is provided to control opening of B, so that when an accident occurs on the line, it is possible to prevent the accident from spreading to other equipment.

Next, the operation of the above embodiment will be explained. When the control power switch 10 shown in FIG. 1 is closed at the start of energization, a reset signal _er is output from the power-on reset circuit 610, and this reset signal activates the tap switching command signal generation circuit 608 and the flip-flop circuits _FF0 to FF. ₆ is reset. At this time, the tap switching command signal generation circuit 608 outputs a signal _v1 instructing to select the transparent tap _t1 ,
The signal e ₃ from the signal source circuit 606 and the signal v ₁ are used to perform an AND operation in the AND circuit A ₁₁ to set the flip-flop circuit FF ₁ . At this time, the AND circuit A ₂₁ outputs a signal of "1", and this signal is input to the amplifier A _n1 through the OR circuit OR ₀ . This allows the thyristor switch S ₁ to pass through the tap t ₁ .
The ignition signals e _g1 and e _g2 are applied to the thyristors SCR ₁ and SCR ₂ , and the preparation for conduction of the thyristor switch S ₁ is completed. On the other hand, turning on of the control power switch 10 is detected by a detection circuit (not shown), and the detection signal of this detection circuit causes the closing circuit of the shroud breaker 5 to operate, and a certain period of time after the power switch 10 is turned on, the shredder breaker 5 is turned on. close. At the time when the shield breaker 5 closes, each thyristor firing signal has already been applied to the thyristor switch _S1 by the above-described operation, so the thyristor switch _S1 immediately becomes conductive. Therefore, no line voltage is applied to the thyristor switches _S2 to _S6 , but only a small voltage approximately corresponding to the tap-to-tap voltage is applied.

After the through tap is selected and energization is started as described above, if the line voltage on the load side decreases due to an increase in load, the voltage adjustment relay 607
The tap switching command signal generation circuit 6
One of the command signals _v2 to _v6 instructing to select the boost taps _t2 to _t6 is output from 08, and an ignition signal is sent to the thyristor switch connected to one of the boost taps _t2 to _t6 . is given. When any of the auxiliary current transformers CT ₁ to _{CT 6} confirms that the thyristor switch to which the ignition signal is applied is conductive and current flows to the tap to which the thyristor switch is connected, the tap current detection circuit A tap current detection signal corresponding to the newly selected tap is output from 609, and this signal causes the ignition signal given to the thyristor switch of the previously selected tap to disappear. As a result, the thyristor switch of the previously selected tap is turned off, and the switching of the tap is completed. For example, when the tap switching command signal generating circuit 608 outputs a signal v ₂ indicating that the tap should be switched to tap t ₂ while the above-mentioned clear t ₁ is selected, the AND of the AND circuit A ₁₂ is established, so the flip-flop circuit FF ₂ is set and the AND of AND circuit A ₂₂ is established. Therefore, a signal "1" is applied to the amplifier A _n2 , and an ignition signal is applied to the thyristor switch _S 2 of the tap t ₂ so that the thyristor switch S ₂ becomes conductive. When the thyristor switch _S2 becomes conductive, a current flows through the tap _t2 , so a detection signal _u2 is output from the tap current detection circuit 609, and the AND of the AND circuit _A32 is established. The output signal "1" of this AND circuit _A32 is sent to the flip-flop circuit corresponding to the adjacent taps _t1 and _t3 via OR circuits _OR1 and _OR3 .
Supplied to the reset terminals of FF ₁ and FF ₃ . By resetting the flip-flop circuit _FF1 , the output signal of the AND circuit _A21 becomes "0", and the input of the amplifier A _n1 becomes "0". Therefore, the supply of the ignition signal to the thyristor switch S ₁ is stopped, and the thyristor switch S ₁ enters the cut-off state when the potential of the anode of each thyristor becomes negative with respect to the cathode.

As in the above embodiment, when the power is turned on, if the thyristor switch of the clear tap is first given an ignition signal to the continuator and then the thyristor switch is turned on, the clear conductor can be turned on at the same time as the thyristor switch is turned on. Since the thyristor switch of one tap is always conductive and no circuit voltage is applied to the thyristor switches of other taps, there is no need to use a thyristor with high withstand voltage, and the price of each thyristor switch can be reduced. Although it is not shown in Fig. 4, when an overcurrent is detected, the thyristor switch with a transparent tap is first turned on unconditionally, and then if necessary (for example, if the current is to be cut off immediately). If the amount is too large), the shion breaker 5 is opened. Therefore, it is only necessary to use a thyristor with a large current capacity in the tap thyristor switch connected to the through tap, and the thyristor of the thyristor switch connected to the through tap can also be used until an overcurrent occurs or the breaker opens. Any material that can withstand overcurrent for a short period of time is sufficient.

Next, a description will be given of the operation when reverse power flows to the regulating transformer 11 from the secondary line and the regulating transformer is reverse excited. If reverse excitation occurs at current time T ₁ , power direction relay 601 generates reverse power detection signal e ₁ as shown in FIG. 5A. Since this signal _e1 is supplied to the set terminal of the flip-flop circuit _FF0 , a signal of logical value "1" (high level) is supplied from the flip-flop circuit _FF0 to the AND circuit _A00 . Therefore, the AND of the AND circuit A ₀₀ is established, and a signal is input to the amplifier A _n1 through the OR circuit OR ₀ . This allows the thyristor switch _S1 of tap t1 to pass through, and the thyristors _SCR1 and _{SCR2 of} S1.
An ignition signal is supplied to the ignition signal. As shown in FIG. 5E, when the transparent tap thyristor switch _S1 conducts and current _I1 flows through the transparent tap _t1 , the tap current detection circuit 609 detects that current has flowed into the transparent tap _t1 . Signal u ₁ occurs, and circuit
AND circuit that is given a signal of “1” from A ₀₀
A ₃₀ AND is established. This makes the OR circuit
Flip-flop circuit FF _{2 ~} through OR ₂ ~ OR ₆
A reset signal is given to FF ₆ , and no ignition signal is given to the thyristor switches of the taps other than the clear tap. At this time, in the tap thyristor switch that was previously energized, one of the two thyristors constituting the thyristor switch, to which a forward voltage is applied between the anode and cathode, is in a conductive state. The one thyristor enters the cut-off state when the polarity of its anode-cathode voltage is reversed at time T2. At this time, a forward voltage is applied between the anode and cathode of the other thyristor, but since the supply of the ignition signal to the other thyristor has already been stopped, the thyristor does not become conductive. Therefore, the thyristor switch of the tap that was previously energized is cut off at time _T2 , and the current _Io flowing through the tap becomes zero at time _T2 (see FIG. 5D). After reverse excitation is detected at time T ₁ , at time T ₂
The time ΔT (the time required to switch the tap) until the thyristor switch of the tap that was previously energized shuts off is a time equivalent to approximately 1/2 cycle of the power supply frequency. If reverse excitation is detected during energization at the transparent tap _t1 , it is fixed to the transparent tap as it is.

Next, when the reverse excitation state disappears at time T ₃ ,
As shown in FIG. 5B, the reverse power extinction detection circuit 602
detects the fall of the reverse power detection signal e ₁ and outputs the reverse power disappearance detection signal e ₂ ′. This signal e ₂ ' is sent to the tap switching command signal generation circuit 60 via the OR circuit OR _x .
8, the tap switching command signal generating circuit 608 is reset at the same time as the reverse power disappears at time _T3 . Next, at time _T4 , which is delayed by a certain period of time from time _T3 , a detection signal _e2 is generated from the delay circuit 603, and this detection signal _e2 is supplied as a reset signal to the flip-flop circuit _FF0 via the OR circuit _ORy . Ru. As a result, the AND of AND circuit A ₀₀ no longer holds true,
Since the AND of AND circuit A ₃₀ will no longer hold,
The state of being fixed to the transparent tap is released, and the state returns to the normal operating state from the state in which electricity is applied at the transparent tap _t1 .

The reason why the delay circuit 603 is provided in the above embodiment is that if the flip-flop circuit _FF0 is reset immediately when the reverse excitation disappears, there is a risk that the current flowing through the tap _t1 will be cut off and a power outage will occur. This is because there is. As in the above embodiment, when the reverse power disappears, the tap switching command signal generation circuit 60
By resetting 8 first, tap t ₁
By setting the flip-flop circuit _FF1 to an initial state in which a command signal for selecting is generated, energization can be reliably continued.

FIG. 6 shows another configuration example of the control circuit used in the present invention. In this example, the reverse power extinction detection circuit 602, the delay circuit 603, and the OR circuit OR _y are omitted, and the OR circuit from the power direction relay 601 is circuit OR _x
A reset signal is continuously supplied to the tap switching command signal generating circuit 608 during the period in which reverse power is generated. The rest of the configuration is the same as the example shown in FIG. 4, and the same operation as in the example shown in FIG. 4 is performed.

In the above explanation, a single-phase circuit was used as an example, but 2
The present invention can be applied in exactly the same manner to a three-phase automatic voltage regulator constructed by V-connecting one regulating transformer or three phase-connecting three regulating transformers.

In Figure 3, each thyristor SCR ₁ , SCR ₂
are each shown as a single thyristor, but in order to increase the current capacity or withstand voltage of the thyristor switch,
Of course, each of SCR ₁ and SCR ₂ may be replaced with a plurality of thyristors connected in parallel or in series.

In the above embodiment, the shield breaker 5 is provided, but if the thyristor switch of the transparent tap is configured with a thyristor that can withstand overcurrent so that the switch is always switched to the transparent tap in the event of an overcurrent, the shield can be disconnected. The container 5 can be omitted.

As described above, according to the present invention, a power directional relay and a control device operated by a signal obtained from the relay are provided, and when the regulating transformer is reverse excited, a period of time until reverse excitation disappears is provided. Since it is fixed to a transparent tap, it is possible to prevent the voltage of the load connected to the line on the primary side of the regulating transformer from becoming insufficient when it is in a reverse excitation state. In addition, when the reverse excitation disappears, the control operation that fixes the tap to the through tap is canceled and the state where the through tap is selected returns to the normal energized state.
There is no power outage when the power is restored, and no excessive voltage is applied to the load connected to the line on the secondary side of the regulating transformer.

[Brief explanation of drawings]

Fig. 1 is a single line diagram schematically showing the overall configuration of an embodiment of the present invention, Fig. 2 is a connection diagram showing main parts of an embodiment of the invention, and Fig. 3 is the configuration of a thyristor switch. Figure 4 is a connection diagram showing an example of the configuration of a control device used in the present invention, Figures 5 A to E are diagrams showing operations when a reverse excitation state occurs, and Figure 6 is a diagram showing an example of the configuration of a control device used in the present invention. FIG. 3 is a connection diagram showing another configuration example of the control device. 1... Substation, 2... Load, 3... Automatic voltage regulator, 4... Line, 6... Control device, 601...
Power direction relay, 602... Reverse power extinction detection circuit, 603... Delay circuit, 608... Tap switching command signal generation circuit.

Claims (1)

[Scope of Claims] 1. A static automatic voltage regulator comprising a regulating transformer connected to a line and a tap selection thyristor switch connected to each tap of the regulating transformer, wherein the regulating transformer 11, a power direction relay 601 that detects reverse power flowing back from the secondary side to the regulating transformer 11, and a power direction relay 601 inserted in the circuit on the power supply side of the regulating transformer 11; After continuously giving an ignition signal to the thyristor switch S ₁ connected to the tap t ₁ which is directly connected to the secondary side and is not converted into voltage, the insulation switch 5 is turned on, and the power direction relay 601 is activated. When reverse power is detected, the primary side and the secondary side of the tap selection thyristor switch are directly connected, and the tap t ₁ is not converted into voltage.
A control operation is performed to conduct only the thyristor switch _S1 connected to the thyristor switch S1 and fix it at the tap _t1 where the primary side and the secondary side are directly connected and no voltage conversion is performed, and when the reverse power disappears, the primary side and 1. A static automatic voltage regulator comprising a control device 6 that releases a control operation that fixes the tap t1 to a tap _t1 that is directly connected to a secondary side and is not converted into a voltage.