JPH0235323B2 - - 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 a thyristor.

Static automatic voltage regulators use thyristors in the mechanical tap changers of conventionally widely used automatic voltage regulators, making them contactless.
It has the feature that there is no limit to the number of times the taps can be switched, and the operating time can be shortened. As shown in FIG. 1A, a conventional static automatic voltage regulator is provided with a series transformer T _S and a regulating transformer _TR , and a thyristor switch is connected to each tap t ₁ to _{t 4} of the regulating transformer.
S ₁ to _{S 4} are connected, and the voltage induced in the secondary winding of the series transformer T _S is applied to the primary winding of the regulating transformer T _R via these thyristor switches. something is known. Here, each thyristor switch has two thyristors SCR ₁ and SCR ₂ connected in antiparallel as shown in Figure 1B, and a surge absorption capacitor _CO and a resistor connected in parallel to these thyristors. It consists of a series circuit of R _O connected to a semiconductor arrester L _A1 , and the line voltage is adjusted to a predetermined value by selecting a tap by making one of the thyristor switches conductive depending on the direction of the line current. It's summery. This type of indirect switching type automatic voltage regulator has the advantage of being able to use low-voltage and inexpensive thyristors, but on the other hand, it requires two transformers, a series transformer and a regulating transformer, which makes the equipment difficult to operate. It has the disadvantage that both size and weight increase, and in particular, as the capacity increases, it becomes difficult to mount it on poles, so it has the disadvantage that only a small capacity can be realized. Furthermore, since this indirect switching type uses a series transformer, it also has the disadvantage of increased loss. In order to eliminate these drawbacks, it is necessary to adopt a direct switching type configuration that does not use a series transformer, but in the case of a direct switching type, each thyristor switch can withstand the entire circuit voltage and the voltage that flows when the load side is short-circuited. This had the disadvantage that it was very expensive because it required something that could withstand short circuit current.

SUMMARY OF THE INVENTION An object of the present invention is to provide a static automatic voltage regulator that does not require expensive thyristors with high withstand voltage and large current capacity, reduces loss, and can be miniaturized.

In order to solve the above problems, the present invention provides a static automatic voltage regulator comprising a regulating transformer connected to the line and a thyristor switch for tap selection connected to each tap of the regulating transformer. According to the present invention, a sheath breaker 5 is inserted in a circuit closer to the power source than the regulating transformer 11, and a control device 6 is also provided. The control device 6 outputs a first overcurrent detection signal e 1 when the load current becomes an overcurrent equal to or higher than a first set value I ₁ and less than a second set value I ₂ , and outputs a first overcurrent detection signal e ₁ and outputs a second overcurrent detection signal e _{1 .} In this case, an overcurrent detection circuit 601 is provided which outputs a first overcurrent detection signal e ₁ and a second overcurrent detection signal e ₂ , and the primary and secondary sides of the regulating transformer 11 are connected at the start of energization. A ignition signal is continuously given to the thyristor switch _S1 connected to a tap that is directly connected and does not undergo voltage conversion (hereinafter referred to as a through tap), and the mustard cutter 5 is turned on.
When the first overcurrent detection signal e ₁ is generated, the thyristor switch S ₁ is made conductive and switched to the through tap t ₁ , and when the second overcurrent detection signal e ₂ is generated, the shield breaker 5 is opened.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below along with embodiments thereof with reference to the drawings.

Figure 2 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. 2, the thick line portion indicates the high voltage portion.

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 adjustment transformer 11, and a terminal 12 _r connected to one end of the transparent tap t ₁ side of the adjustment transformer 11 and an adjustment terminal. Terminals _12'r connected to the other end of the transformer 11 are respectively connected to the load-side lines. The other ends of the thyristor switches 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 through the main contact 51 _A of the breaker 5. and is connected to the input terminal _12S . Also, the end connected to the output terminal _12'r of the regulating transformer 11 is connected to the main contact 51 of the disconnector 5.
It is connected to the input terminal 12 _'S through _B , and the line on the power supply side (substation side) is connected to the input terminals _12S and 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 to this, a thyristor switch connected to one of the regulating transformers is continuously supplied with an ignition signal to turn on the mustard cutter 5;
It is also configured to control the shield breaker and thyristor switch so that the shield breaker 5 is opened when an overcurrent is detected by the current transformer CT.

An example of the configuration of the control device 6 is shown in FIG. In the same figure, 601 is an overcurrent detection circuit, and this detection circuit is a current transformer installed in the breaker 5.
With the output of the CT as input, when the line current exceeds the first set value I ₁ (for example, 500A), the first overcurrent detection signal e ₁ with a logical value of "1" is output, and the line current is Second set value I ₂ higher than the first set value
(for example, 2500A) or more, the first overcurrent detection signal _e1 and the second overcurrent detection signal whose logic value is "1" are sent.
Outputs overcurrent detection signal _e2 . Such an overcurrent detection circuit includes, for example, a rectifier that rectifies the output of a current transformer CT, and first and second comparators that compare the output of the rectifier with first and second set values, respectively. be done.

Second detection signal e ₂ obtained from the above detection circuit
is a signal instructing to open the circuit breaker 5, and this signal is transmitted by a transistor whose emitter is grounded.
It is supplied to the base of Tr ₁ . transistor
The collector of Tr ₁ is connected to the positive output terminal of the DC power supply 602 through a parallel circuit of the coil of the relay RY ₁ and the diode D ₁ , and the transistor Tr ₁ becomes conductive when the second detection signal e ₂ is generated. relay RY ₁ is energized. Reference numeral 603 denotes a control power-on detection circuit that detects that the switch 10 shown in _FIG . The collector of ₂ is connected to the DC power supply 6 through a parallel circuit with the coil of relay RY ₂ and diode D ₂ .
It is connected to the positive input terminal of 02.

Relays RY ₁ and RY ₂ each have a normally open contact RY _1a
and RY _2a , and these contacts are connected to a circuit breaker control circuit 605. The breaker control circuit 605 is a full-wave rectifier to which an AC voltage of 100V is input through the control power switch 10 shown in FIG.
Rec ₁ is provided between the output terminals of this full wave rectifier and the coil of the contact RY _2a and relay RY ₃ and relay RY ₄
Series circuit with normally closed contact RY _4b and diode D ₃
A series circuit of resistor R ₁ and capacitor C ₁ is connected in parallel. Coil and normally closed contacts of relay RY ₃
A series circuit of the coil of relay RY ₄ and a normally open contact RY _4a of relay RY ₄ is connected in parallel to both ends of the series circuit with RY _4b , and the normally open contact is connected to the connection point of resistor R ₁ and capacitor C ₁ . One end of RY _1a is connected.

In the example shown in FIG.
Main contacts 51 _A and 5 that open and close the main tracks respectively
1 _B are provided with auxiliary contacts 52 _A and 52 _B that open and close in conjunction with these main contacts, and one end of the auxiliary contacts 52 _A and 52 _B is commonly connected to the negative output terminal of the rectifier Rec ₁ . . Also, the auxiliary contact 52
The other end of _A is connected to the other end of the normally open contact RY _1a via the trip coil _53T , and the other end of the auxiliary contact _52B is connected to the connection point between the coil of relay RY ₄ and contact RY _4a . . The shield breaker 5 is also provided with a closed coil _53C , which is connected between the DC output terminals of the rectifier _{Rec1 and} the relay _RY3C.
are connected in parallel via the normally open contacts RY _3a .

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 F ₁ to F ₆ are filter circuits for direct current conversion and noise removal consisting of a full-wave rectifier Rec ₃ , a resistor R ₂ , and a capacitor C ₂ . , 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 ,
The first detection signal _e1 of the overcurrent detection circuit 601 is input to the set terminal of _FF0 . Therefore, the first detection signal _e1 is generated and the flip-flop circuit
When FF ₀ is set, the AND circuit A ₀₀ outputs a signal of "1", and this signal is input to the amplifier A _n1 through the OR circuit OR ₀ , so that the ignition signal e _g1 and the pulse output circuit P ₁ are output. e _g2 is output. These signals are converted into direct current through a filter circuit _F1 and supplied to the gates of thyristors _SCR1 and _SCR2 of a thyristor switch _S1 connected to a transparent tap _t1 , respectively. In this state, when the circuit breaker 5 is turned on, the thyristors SCR ₁ and SCR ₂ become conductive alternately during the positive and negative half cycles of the line voltage, thereby connecting the line on the power supply side 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
is comprised of, for example, a shift register, and outputs 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 the AND circuits _A11 to _A16 are input to the set terminals of the flip-flop circuits FF1 to FF6, respectively, and the outputs of the AND circuits _A11 to _A16 are input to the set terminals of the flip-flop circuits FF1 to _FF6 , respectively.
The output of FF ₆ is input to one input terminal of 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 ,
In addition, the output of the AND circuits A ₂₂ to _{A 26} is output from the amplifier A _n2 to
Each is input to A _n6 . Amplifier A _n2 ~
The output of A _n6 is supplied to the thyristors of thyristor switches S ₂ to S 6 which select taps t ₂ to t ₆ via pulse output circuits P ₂ to _{P 6} and filter circuits F ₂ to _{F 6 ,} respectively. In addition, 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 22} are supplied to the AND circuits A 32 to A ₃₁ , respectively.
Supplied to one input terminal of A ₃₆ . Tap current detection circuits u ₁ to u ₆ obtained from tap current detection circuit 609 are input to the other input terminals of AND circuits A ₃₁ to A ₃₆ , respectively. 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. Enter u ₁ ′ to u ₆ ′ and tap t ₁ to _{t 6}
It outputs tap current detection signals u ₁ to _{u 6} to the output terminals corresponding to the respective taps, and when one of the taps is selected and current flows through that tap,
Tap current detection circuit 609 outputs a tap current detection signal corresponding to the selected tap. These tap current detection signals
Among 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 other input terminal of the AND circuit A _{30 is supplied to the input terminal of the AND circuit A 30} . The output of AND circuit A ₀₀ is supplied. Also, the output of AND circuit A ₃₀ is OR circuit OR ₂ ~
The output _{of AND circuit A 31 is} input to OR circuit OR ₂ . The output of AND circuit A ₃₂ is input to OR circuits OR ₁ and OR ₃ , and the AND circuit
The output of _A33 is input to OR circuits _OR2 and _OR4 . Furthermore, the output of AND circuit A ₃₄ is OR circuit OR ₃
and OR ₅ , the output of AND circuit A ₃₅ is OR circuit
Input to OR ₄ and OR ₆ respectively, AND circuit
The output of _A36 is input to the OR circuit _OR5 . The outputs of OR circuits OR ₁ to OR ₆ are supplied to the reset terminals of flip-flop circuits FF ₁ to FF ₆ , respectively.
When signals in the state of "1" are output from OR circuits OR ₁ to OR ₆ , flip-flop circuits FF ₁ to
When the output of FF ₆ becomes "0", AND circuit A ₂₁ ~ _{A 26}
The output is set to "0". In order to reset the control circuit when the switch 10 is turned on,
A power-on reset circuit 610 is provided, and a reset signal e _r obtained from this circuit is sent to the tap switching command signal generation circuit 608 and the flip-flop circuit.
FF ₀ reset terminal and OR circuit OR ₁ to 1 of OR ₆
are input to both input terminals. Furthermore, AND circuit A ₀₀ , A ₁₁ ~ _{A 16} ...A ₃₁ ~A ₃₆ , OR circuit
Electric power for operating each part of the control circuit such as OR ₀ to OR ₆ and flip-flop circuits FF ₀ to FF ₆ is provided by a constant voltage power supply circuit 611 to which the output of the control power transformer 8 is input via the switch 10. It's becoming like that.

Next, the operation of the above embodiment will be explained. When the control power switch 10 is closed as shown in FIG. 5A at the start of energization, a reset signal e _r (see FIG. 5D) is output from the power-on reset circuit 610, and this reset signal activates the tap switching command signal generation circuit. 6
08 and flip-flop circuits FF ₀ to FF ₆ are reset. At this time, the tap switching command signal generation circuit 608 outputs a signal v ₁ instructing to select the transparent tap t ₁ , and the AND circuit A ₁₁ is generated using the signal e ₃ from the signal source circuit 606 and the signal v ₁ . The AND is established and the flip-flop circuit _FF1 is set. 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 for clear tap t ₁
thyristor switch S ₁ thyristor SCR ₁ ,
The ignition signals e _g1 and e _g2 (see FIG. 5B) of SCR ₂ are applied, and the thyristor switch S ₁ is ready to conduct. On the other hand, turning on of the control power switch 10 is detected by the control power on detection circuit 603, and a signal is given to the delay circuit 604 from this detection circuit. The delay circuit 604 applies a signal to the base of the transistor Tr ₂ with a delay of a certain delay circuit ΔT after the switch 10 is turned on, thereby making the transistor Tr ₂ conductive. This energizes relay RY ₂ and closes its contact RY _2a . Relay when contact RY _2a closes
Since RY ₃ is energized and the contact RY _3a is closed, the closed coil _53C is energized. The excitation of the closed coil 53 _C closes the main contacts 51 _A and 51 _B of the shield breaker 5, and along with this, the auxiliary contact 52
_A and 52 _B are also closed. In this way, when the control power switch 10 is turned on, the breaker 5 closes after a certain period of time ΔT (see FIG. 5C), but by the time the breaker 5 closes, the operation is already complete Since the ignition signal is applied to each thyristor of the thyristor switch _S1 , the thyristor switch _S1 immediately becomes conductive. Therefore, thyristor switch S ₂
No line voltage is applied to ~ _S6 , and 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 60
7, one of the command signals _v2 to v6 instructing to select the boost taps _t2 to _t6 is output from the tap switching command signal generation circuit 608, and the boost taps _t2 to _{t6 are} selected. An ignition signal is given to a thyristor switch connected to one of the thyristor switches. 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, if the tap switching command signal generation circuit ₆₀₈ outputs a signal _v2 indicating that the tap should be switched to tap _t2 while the transparent tap t1 is selected, the AND of the AND circuit _A12 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.

Next, we will explain the operation when an overcurrent flows due to a short circuit accident on the load side while one of the taps is selected and the load is energized. This overcurrent is the first
If the set value I ₁ (e.g. 500A) or more, the second set value I ₂
(for example, 2500 A), only the first detection signal _e1 is generated from the overcurrent detection circuit 601.
At this time, since the flip-flop circuit FF ₀ is set, the AND of the AND circuit A ₀₀ is established, and a signal "1" is input to the through-tap amplifier A _n1 through the OR circuit OR ₀ . Therefore, the thyristor switch _S1 becomes conductive and the clear tap _t1 is selected. As a result, the detection signal _u1 is output from the tap current detection circuit 609, so the AND of the AND circuit _A30 is established, and the output signal "1" of the AND circuit _A30 is passed through the OR circuits _OR2 to _OR6 to the flip-flop circuit FF. ₂ to _FF6 reset terminals, respectively. This creates a flip-flop circuit.
All of FF ₂ to _{FF 6} are reset, and even if any of the taps t ₂ to _{t 6} is selected, the supply of the ignition signal to the thyristor switch of the selected tap is stopped. 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 is turned off when the polarity of the anode-cathode voltage is reversed. 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. In this way, if an overcurrent of less than the second set value _I2 occurs, switching to the open tap is performed unconditionally. If current flows through the transparent tap, it will remain fixed to the transparent tap.

Next, when an overcurrent equal to or greater than the second set value I ₂ flows, the overcurrent detection circuit 601 simultaneously outputs the first and second detection signals e ₁ and e ₂ . In this case, the first detection signal e ₁ causes an unconditional tap t ₁
The switching to is performed in the same way as above.
Since the second detection signal e ₂ is input to the base of the transistor Tr ₁ , the transistor Tr ₁ becomes conductive and the relay RY ₁ is excited. Contact RY _1a is therefore closed. The disconnector 5 is now closed and the auxiliary contact 52 _A ,
Since _{the contact RY 1a is} closed, the trip coil 53T is excited. This releases the mechanical lock of the shield breaker 5, opens the main contacts _51A and _51B , and opens the auxiliary contacts _52A and 5.
2 Open _B too. In this way, when an overcurrent exceeding the second set value is detected, the switch is first unconditionally switched to the through tap, and then the breaker 5 is switched on.
will be held. The sequence of operations in this case is shown in FIGS. 6A to 6C with time on the horizontal axis, where A shows the on/off operation of the thyristor switch of the tap during energization, and _FIG . This shows the on/off operation of thyristor switch _S1 . In addition, C in the same figure shows the operation of the cutter 5. In FIG. 6, when an overcurrent occurs at time T ₁ , the thyristor switch S ₁ of the open tap t 1 becomes conductive, and it takes a time ΔT ₁ for the thyristor switch S ₁ of the current-carrying tap to shut off, but this time ΔT ₁ is normally equivalent to about 1/2 cycle of the power supply voltage. Further, the time ΔT ₂ from when an overcurrent occurs until the mustard cutter 5 opens is a time corresponding to about 3 cycles.

Once the fault has been removed, the breaker is re-closed, but in this case the ignition signal has already been given to the thyristor switch S ₁ of the through tap t ₁ , so when the breaker is closed, the breaker is turned on again. The thyristor switch _S1 in the tap becomes conductive first. If it is necessary to select a boost tap, the operation of sequentially selecting taps _t2 to _t6 is performed until a predetermined tap is reached.

With the configuration of the above embodiment, since the tap is unconditionally switched to the through tap when an overcurrent occurs, it is possible to prevent excessive current from flowing into the thyristor switch of a tap other than the through tap. In addition, when turning on the power, first the thyristor switch with a clear tap is continuously given an ignition signal to turn on the thyristor switch, so the thyristor switch with a clear tap must be turned on at the same time as the breaker is turned on. conduction. Therefore, when the circuit breaker is turned on, the full circuit voltage is not applied to each thyristor switch. Also, as is well known, when a circuit breaker is turned on, an inrush current, which is a transient current, flows due to the phase of the circuit voltage, but if the thyristor switch connected to the through tap is always made conductive when a circuit breaker is turned on, This can prevent inrush current from flowing to other thyristor switches. Therefore, the current capacity of other thyristor switches can be reduced.
For these reasons, only the open-tap thyristor switch may use a thyristor with a large current capacity, and the other tap thyristor switches can be constructed from inexpensive thyristors with a small current capacity. In addition, transparent tap thyristor switches only need to withstand overcurrent for a short period of time before the overcurrent occurs and the circuit breaker opens, which is not necessary for conventional direct switching automatic voltage regulators. A large capacity thyristor is not required.

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.

As described above, according to the present invention, a direct switching type automatic voltage regulator using a thyristor switch is combined with a thyristor switch, and when the breaker is turned on, the thyristor switch connected to the through tap is continuously activated. Since the ignition signal is given to make the thyristor switch close, the entire circuit voltage is not applied to the thyristor switch when the breaker is closed, and the thyristor switch other than the one connected to the through tap is It is possible to prevent the inrush current that occurs when the thyristor switch is turned on or the circuit breaker is turned on from flowing. Further, according to the present invention, when the load current becomes an overcurrent exceeding the first set value, the thyristor switch connected to the through tap is made conductive to perform a switching operation to the through tap, and the load current is brought to the first setting. When the value exceeds the second set value, which is larger than the second set value, the circuit breaker opens, so when an overcurrent occurs, the overcurrent flows through the thyristor switches other than the one connected to the through tap. Moreover, it is possible to prevent overcurrent from flowing for a long time to the thyristor switch connected to the transparent tap. Therefore, according to the present invention, the thyristor switches other than the thyristor switch connected to the through tap can be constructed using inexpensive thyristors with small current capacity, and the thyristor switches connected to the through tap can also be configured using the conventional thyristor switches. Direct-switching automatic voltage regulators do not require large-capacity thyristors like those required with direct-switching automatic voltage regulators, and do not use series transformers, making the device smaller and lighter. There is an advantage that a static automatic voltage regulator can be provided at a low cost by taking advantage of the advantages of the device.

[Brief explanation of drawings]

FIG. 1A is a connection diagram showing an example of the configuration of a conventional static automatic voltage regulator, FIG. 1B is a configuration diagram of a thyristor switch, and FIG. 2 schematically shows the overall configuration of an embodiment of the present invention. 3 is a connection diagram showing essential parts of an embodiment of the present invention, FIG. 4 is a connection diagram showing an example of the configuration of a control device used in the present invention, and FIGS. FIGS. 6A to 6C are diagrams showing operations when the power is turned on when using the control device shown in FIG. 6, and FIGS. 6A to 6C are diagrams showing operations when overcurrent is detected. 1... Substation, 2... Load, 3... Automatic voltage regulator, 4... Line, 5... Line breaker, 6... Control device.

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 When the load current becomes an overcurrent of more than the first setting value (I ₁ ) and less than the second setting value (I ₂ ), the first An overcurrent detection circuit 601 that outputs an overcurrent detection signal e _{1 of} , and outputs a first overcurrent detection signal e ₁ and a second overcurrent detection signal e ₂ when the value exceeds a second set value (I ₂ ). The primary side and the secondary side of the regulating transformer 11 are directly connected at the start of energization, and the voltage is not converted.
After continuously giving an ignition signal to the thyristor switch S ₁ connected to t ₁ , the breaker 5 is turned on,
Further, when the first overcurrent detection signal _e1 is generated, the thyristor switch _S1 is made conductive and switched to the tap _t1 where the primary side and the secondary side are directly connected and voltage conversion is not performed, and the second overcurrent detection signal
_1. A static automatic voltage regulator comprising: a control device 6 that opens the shield breaker 5 when an error occurs.