JPH0235324B2 - 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 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 TS and a regulating transformer TR, and a thyristor switch S ₁ is connected to each tap t ₁ to _{t 4} of the regulating transformer. _An indirect switching type is known in which the voltage induced in the secondary winding of the series transformer TS is applied to the primary winding of the regulating transformer TR via these thyristor switches. It is being Here, each thyristor switch is as shown in Figure 1B.
It consists of two thyristors SCR ₁ and SCR ₂ connected in antiparallel, and the line voltage is adjusted to a predetermined value by selecting the tap by making one of the thyristor switches conductive according to the line current. It's getting old. This type of indirect switching type automatic voltage regulator has the advantage of being able to use a low-voltage thyristor, but on the other hand, it requires two transformers, a series transformer and a regulating transformer, which makes the device size and It has the disadvantage that the weight also increases, 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 shortcomings, 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 short circuit that flows when the load is short-circuited. It had the disadvantage that it was very expensive because it required something that could withstand the current.

SUMMARY OF THE INVENTION An object of the present invention is to provide a static automatic adjustment device that does not use a thyristor with high withstand voltage and large current capacity, reduces loss, and can be downsized.

The present invention relates to a static automatic voltage regulator comprising a regulating transformer connected to a line and a thyristor switch for tap selection connected to each tap of the regulating transformer. 11, the first automatic switch 6 inserted into the circuit on the load side of the adjustment transformer 11, and the power supply side terminal of the shield breaker 5. The present invention is characterized by comprising a second automatic switch 7 that opens and closes between the terminal and the load side terminal of the first automatic switch 6, and a control device 8. The control device 8 has a first load current.
When the overcurrent is greater than or equal to the set value I ₁ and less than the second set value I ₂ , the first overcurrent detection signal e ₁ is output, and when it is greater than or equal to the second set value I ₂ , the first overcurrent detection signal is output. _e1 and a second overcurrent detection signal e2, 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. It is called tap.) t ₁
After continuously giving an ignition signal to the thyristor switch S ₁ connected to the thyristor switch S 1 , the second automatic switch 7 is closed, and the circuit breaker 5 is turned on and the first automatic switch 6 is closed in sequence. After this, the second automatic switch 7 is opened, and when the first overcurrent detection signal _e1 is generated, the thyristor switch _S1 is made conductive, so that the primary side and the secondary side are directly connected and no voltage conversion occurs. When the switch is switched to tap _t1 and the second overcurrent detection signal _e2 is generated, the circuit breaker 5 is opened, and then the first automatic switch 6 is opened and the second automatic switch 7 is closed. Have them do it in order.

With the above configuration, when an overcurrent is detected, the thyristor can be protected by opening the circuit breaker, so a thyristor with a small current capacity can be used.

In addition, if a configuration is adopted in which the second automatic switch is closed after the shiya breaker opens as described above, the shiya breaker is bypassed by the second automatic switch and the power supply side and the load side are connected. If the fault has been resolved, the power supply to the load can be restarted immediately, and if the fault has not been resolved, the substation switch can be immediately activated.

Furthermore, as mentioned above, if the ignition signal is continuously given to the thyristor switch connected to the through-tap of the regulating transformer at the start of energization to cause the mustard or breaker to close, the thyristor is fully activated. It is possible to prevent circuit voltage from being applied.

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 together with a power distribution system. In the figure, 1 is a substation, 2 is a load, and 3 is a direct switching switch connected to a line 4 connecting the substation and the load. type static automatic voltage regulator,
Reference numeral 5 denotes a circuit breaker inserted in a circuit closer to the power source than the voltage regulator 3. 6 is a first automatic switch inserted into the circuit on the load side of the voltage regulator 3; This is a second automatic switch provided to open and close. 8 is a control device that controls the voltage regulator 3, the shield breaker 5, the first automatic switch 6, and the second automatic switch 7; The output of the fluid CT is input. 9 is a control power transformer connected to the line on the power supply side than the cutter 5, and the output voltage (usually 100V) of this transformer is connected to the control device 8 through the control power cable 10 and the control power switch 11. is supplied to. 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 regulation transformer 11, and one end of the transparent tap t ₁ side of the regulation transformer 11 and the other ends of the regulation transformer 11. The ends are connected to output terminals 12r and 12'r through contacts 61A and 61B of the first automatic switch 6, and load-side lines are connected to these output terminals, respectively. The other ends of thyristor switches S ₁ to _{S 6} are reactors L ₁ to _{L 6} , respectively.
The other ends of the reactors L ₁ to _{L 6} are commonly connected and connected to the input terminal 12s via the main contact 51A of the shield breaker 5. The other end connected to the output terminal 12'r of the regulating transformer 11 is connected to the input terminal 1 through the main contact 51B of the disconnector 5.
2's, and the input terminals 12s, 12's
The line on the power supply side (substation side) is connected to. Furthermore, the power supply side terminals of the main contacts 51A and 51B of the breaker 5 and the contacts 61A and 61B of the first automatic switch 6
Contacts 71A and 71B of the second automatic switch 7 are connected to open and close the terminals on the load side of the second automatic switch 7, respectively.

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 8 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, there is also a control operation that continuously applies a firing signal to the thyristor switch connected to a specific tap on the regulating transformer to close or open the disconnector, and when an overcurrent is detected. At times, the capacitor breaker 5 is opened, the first automatic switch 6 is opened, and when the opening of the tap is detected, the second automatic switch 7 is closed. The automatic switch is configured to perform a control operation to control the automatic switch.

An example of the configuration of the control device 8 is shown in FIG. In the same figure, 801 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 802 through a parallel circuit of the coil of the relay RY ₁ and the diode D ₁ , and when the second detection signal e ₂ is generated, the transistor Tr ₁ becomes conductive. relay RY ₁ is energized. 803 is a control power-on detection circuit that outputs one pulse signal when the switch 10 shown in _FIG. The collector of the transistor Tr ₂ is connected to the positive output terminal of the DC power supply 802 via a parallel circuit of the coil of the relay RY ₂ and the diode D ₂ . The output of the control power-on detection circuit 803 is also inputted to the base of the transistor Tr ₃ whose emitter is grounded through the OR circuit ORa, and the collector of the transistor Tr ₃ receives direct current through the parallel circuit of the coil of the relay RY ₃ and the diode D ₃ . power supply 8
It is connected to the positive side output terminal of 02. 80
5 is the opening of the tap, that is, the tap of the regulating transformer 11.
This tap open detection circuit 805 outputs a detection signal when it is detected that all of t ₁ to _{t 6} are disconnected from the power supply and are not energized. An input signal is obtained from the circuit 811, and its output signal is supplied to the base of the transistor _Tr3 via the delay circuit 806 and the OR circuit ORa.

The relay RY ₁ has a normally open contact RY ₁ a and a normally closed contact RY ₁ b, and the relay RY ₂ has a normally open contact RY ₂ a, RY' ₂ a and a normally closed contact RY ₂ b. . Also relay RY ₃
has a normally open contact RY ₃ a, and the coil of relay RY ₄ is connected to DC power supply 802 via this normally open contact RY ₃ a and the above-mentioned normally closed contact RY ₂ b. relay
RY ₄ has normally open contacts RY ₄ a and RY′ ₄ a, and one normally open contact RY ₄ a is connected in parallel with the normally open contact RY ₃ a. In addition, contact RY ₂ a of relay RY ₂ and contact RY ₁ b of relay RY ₁ are connected in series, and the coil of relay RY ₅ is connected to DC power supply 8 via these contacts.
Connected to 02. Relay RY ₅ is a normally open contact
RY ₅ a and RY′ ₅ a, one normally open contact RY ₅ a is connected in parallel to the contact RY ₂ a.

Normally open contacts RY ₁ a and relays RY ₁ and RY ₂
RY′ ₂ a is connected to the breaker control circuit 807. The breaker control circuit 807 is connected from the control power transformer 9 in FIG. 2 through the control power switch 11.
It is equipped with a full-wave rectifier Rec ₁ to which an AC voltage of 100V is input, and the contact point is connected between the output terminals of this full-wave rectifier.
Series circuit of RY′ ₂ a, coil of relay RY ₃ , normally closed contact RY ₇ b of relay RY ₇ , diode D ₄ and resistor
A series circuit of R ₁ and capacitor C ₁ is connected in parallel. A series circuit consisting of the coil of relay RY ₇ and normally open contact RY ₇ a of relay RY ₇ is connected in parallel to both ends of the series circuit consisting of the coil of relay RY ₆ and normally closed contact RY ₇ b, and resistors R ₁ and RY 7 a are connected in parallel. One end of the normally open contact RY ₁ a is connected to the connection point of the capacitor C ₁ .

In the example shown in FIG.
Main contacts 51A and 5 that open and close the main tracks respectively
1B are provided with auxiliary contacts 52A and 52B that open and close in conjunction with these main contacts, and the auxiliary contact 52A
and 52B have one end commonly connected to the negative output terminal of the rectifier Rec ₁ . The other end of the auxiliary contact 52A is connected to the other end of the normally open contact RY1a via a trip coil _53T , and the other end of the auxiliary contact 52A is
The other end of 2B is connected to the connection point between the coil of relay RY ₇ and contact RY ₇ a. The breaker 5 is also provided with a closed coil 53C, which is connected in parallel between the DC output terminals of the rectifier Rec ₁ via a normally open contact RY ₆ a of a relay RY ₆ .

The first and second automatic switches 6 and 7 are constantly energized automatic switches that do not have a mechanical lock mechanism that closes only while the closed coil CC is energized, and the closed coil CC of these switches is It is connected between input terminals a and b via a resistor _R2 . A series circuit of resistors R ₃ and R ₄ and the coil of relay X is also connected between input terminals a and b, and the coil of relay Mc is connected in parallel to both ends of the series circuit via the normally closed contact It is connected. Capacitor _C2 is connected in parallel to both ends of the coil of relay X, and normally open contact Mca of relay Mc and normally closed contact X'b of relay X are connected in parallel to both ends of resistor _R2 and both ends of resistor _R3 , respectively. has been done. Further, a flywheel diode _D5 for delaying the opening operation is connected in parallel to both ends of the closed coil CC of the second automatic switch 7. The output of the transformer 9 is inputted between the input terminals a and b of the first automatic switch 6 via the control power switch 11. The output of the full-wave rectifier Rec ₂ is connected to the normally open contact of the relay RY ₅ .
It is applied via RY′ ₅ a, and a smoothing capacitor C ₃ is connected in parallel to the output terminal of the rectifier Rec ₂ .
Further, between the input terminals a and b of the second automatic switch 7, the output of the full-wave regulator Rec ₃ to which the output of the control power transformer 9 is inputted via the switch 11 is applied. A smoothing capacitor _C4 is connected in parallel between the output terminals of the full-wave rectifier _Rec3 .

When voltage is applied between the input terminals a and b of the first automatic switch 6, the relay Mc
Current flows through the coil and contact Mca closes. As a result, the closed coil CC is excited, and the contacts 61A and 61B of the automatic switch 6 are closed. The voltage applied between input terminals a and b is also applied to capacitor C ₂ via contact X'b and resistor R ₄ , and when charging of capacitor C ₂ is completed, relay X is energized. This opens contacts Xb and X′b,
Relay Mc is deactivated. In this state, the excitation current of the closed coil CC is limited by the resistor _R2 ,
The current in the closed coil CC is reduced to the holding current required to keep the switch closed.
Further, the excitation current of relay X is also limited to the holding current by resistors R ₃ and R ₄ . When the voltage between input terminals a and b is removed, the closed coil CC is deenergized and the contacts 61A and 61B are opened. The operation of the second automatic switch 7 is controlled by the flywheel diode D ₅
This is the same as above except that the opening operation is delayed.

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, Am ₁
~Am ₆ is an amplifier consisting of transistors, P ₁ ~P ₆
consists of a DC power supply E and a pulse transformer Pt, and when a signal of "1" is input to each of the amplifiers Am ₁ to _{Am 6} , pulsed ignition signals eg ₁ and eg are generated.
The pulse output circuit that outputs eg ₂ at the same time, F ₁ to F ₆ are filter circuits that combine direct current conversion and noise removal, consisting _of a full-wave rectifier Recf, a resistor Rf, and a capacitor _Cf. A circuit for on/off control is configured. More specifically, a signal source circuit 808 is connected to one input terminal of each of the AND circuits A ₀₀ , A ₁₁ to A ₁₂ and A ₂₁ to _{A 26} .
_The rectangular _pulse signal e ₃ obtained from
Am ₁ is entered. The output of the flip-flop circuit FF ₀ is input to the other input terminal of the AND circuit A ₀₀ , and the first detection signal e ₁ of the overcurrent detection circuit 801 is input to the set terminal of FF ₀ . Therefore, when the first 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 Am ₁ through OR ₀ , thereby outputting the ignition signals eg ₁ and eg ₂ from the pulse output circuit P ₁ . These signals are converted into direct current through the filter circuit _F1 and supplied to the gates of thyristors _SCR1 and _SCR2 of the thyristor switch _S1 connected to the through tap _t1 , respectively. When the circuit breaker 5 is turned on in this state, the thyristors SCR ₁ and SCR ₂ become conductive alternately during the positive and negative half cycles of the line voltage.
Connect the line on the power supply side to tap _t1 .

The other input terminals of the AND circuits A ₁₁ to _{A 16} are provided with outputs v ₁ to v ₆ of a tap switching command signal generation circuit 810 controlled by a voltage regulating relay 809, respectively.
is entered. Tap switching command generation circuit 81
0 consists of a shift register, for example, and outputs one of the signals v ₁ to v ₆ instructing to select the taps t ₁ to t ₆ , respectively, in response to the signal from the voltage adjustment relay 809. 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 Am ₁ via the OR circuit OR ₀ ,
In addition, the outputs of AND circuits A ₂₂ to _{A 26} are output from amplifiers Am ₂ to
Am ₆ is entered respectively. Amplifier Am ₂ ~
The output of Am ₆ is supplied to the thyristors of thyristor switches S ₂ -S ₆ which select taps t ₂ -t ₆ via pulse output circuits P ₂ -P ₆ and filter circuits F ₂ -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 ₃₂ , respectively.
Supplied to one input terminal of A ₃₆ . Tap current detection signals u ₁ to u ₆ obtained from the tap current detection circuit 811 are input to the other input terminals of the AND circuits A ₃₁ to A ₃₆ , respectively. The tap current detection circuit 811 rectifies the outputs of the auxiliary current transformers CT ₁ to _{CT 6} provided for the taps t ₁ to t ₆ , respectively, with a full-wave rectifier Rec ₄ , and converts the outputs to the constant voltage diodes.
Input the signals u′ ₁ to u′ ₆ made constant voltage by ZD and tap
Tap current detection signals u ₁ to u ₆ are output to the output terminals corresponding to t ₁ to t ₆ , respectively. When one of the taps is selected and a current flows through that tap, the tap current detection circuit 311 outputs the tap current detection signals u 1 to u 6 to the output terminals corresponding to t 1 to t 6, respectively. A tap current detection signal corresponding to the selected tap is output. 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 . The output of the AND circuit A ₀₀ is supplied to the other input terminal. Also, the output of AND circuit A ₃₀ is an OR circuit
It is input to OR ₂ to OR ₆ , and the output of AND circuit A ₃₁ is input to OR circuit OR ₂ . AND circuit A ₃₂
The output of AND circuit A33 is input to OR circuits OR ₁ and OR ₃ , and 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 input 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 ₅ . ing.
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", the outputs of AND circuits A ₂₁ to A ₂₆ become "0". In order to reset the control circuit when the switch 10 is turned on, a power-on reset circuit 812 is provided, and a reset signal e _r obtained from this circuit is sent to the tap switching command signal generation circuit 810 and the flip-flop circuit FF _{0 .}
and one input terminal of OR circuits _OR1 to _OR6 , respectively. Furthermore, AND circuit A ₀₀ , A ₁₁ ~A ₁₆ ...A ₃₁ ~A ₃₆ , OR circuit OR ₀ ~
The power for operating each part of the control circuit such as OR ₆ and the flip-flop circuits FF ₀ to _{FF 6} is now provided by a constant voltage power supply circuit 813 into which the output of the control power transformer 9 is input via the switch 11. ing.

Next, the operation of the above embodiment will be explained. When the control power switch 11 is closed as shown in FIG. 5A at the start of energization, a reset signal e _r (see FIG. 5) is output from the power-on reset circuit 812, and this reset signal causes the tap switching command signal generation circuit 81 to be output.
0, and flip-flop circuits FF ₀ -FF ₆ are reset. At this time, the tap switching command signal generating circuit 810 _outputs a signal _v1 instructing selection of the transparent tap t1, and the AND of the AND circuit _A11 is established to set the flip-flop circuit _FF1 . At this time, the AND circuit A ₂₁ outputs a square wave signal, and this signal is passed through the OR circuit OR ₀ to the amplifier.
Entered into Am ₁ . This allows the thyristor switch _S1 of tap t1 to pass through, and the thyristors _SCR1 and _{SCR2 of} S1.
ignition signals eg ₁ and eg ₂ (see Figure 5B) are given,
Preparation for conduction of thyristor switch _S1 is completed.
On the other hand, the turning on of the control power switch 11 is detected by the control power turning on detection circuit 803, and from this detection circuit a signal is sent to the transistor Tr ₃ through the OR circuit ORa.
gives pulse-like signals. This causes transistor Tr ₃ to conduct, energizing relay RY ₃ and closing its contact RY ₃ a. Closing contact RY ₃ a energizes relay RY ₄ and is self-held by contact RY ₄ a. At this time, since the contact RY' ₄ a is also closed, the automatic switch 7 is closed as shown in FIG. 5C. Since the pulsed output of the above-mentioned closing detection circuit 803 is also supplied to the transistor Tr ₂ through the delay circuit 304, a certain period of time △ after the switch 11 is closed.
T ₁ delay, transistor Tr ₂ turns on detection circuit 803
conducts for a time corresponding to the width of the output pulse, and relay RY ₂ operates for a short time. Contacts of relay RY ₂
When RY ₂ a closes, relay RY ₅ is energized and its contact RY' ₅ a closes, and the closure of contact RY' ₂ a closes the shield breaker 5. Furthermore, the relay RY ₅ is self-held by closing the contact RY ₅ a, and the automatic switch 6 is closed by closing the contact RY' ₅ a. Also, when contact RY ₂ b opens, relay RY ₄ is deenergized, so contact
RY′ ₄ a opens, but the deenergization of the closed coil CC is delayed due to the flywheel diode D ₅ , so
The automatic switch 7 opens after a certain delay time ΔT ₂ has elapsed after the automatic switch 6 has closed, as shown in FIG. 5C. As soon as the automatic switch 7 opens, Fig. 5 F
As shown in , the thyristor switch S ₁ of the through-tap to which the ignition signal has already been applied becomes conductive, and current flows through the through-tap t ₁ . In this way, since the thyristor switch S ₁ becomes conductive immediately, no line voltage is applied to the thyristor switches S ₂ to _{S 6} , and only a small voltage approximately equivalent to the tap-to-tap voltage is applied to the thyristor switches S 2 to S 6. . Here, the delay times △T ₁ and △T ₂ are, for example, △T ₁ = △T ₂ = 1
Set it to about [sec].

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 80
9, the tap switching command signal generation circuit 810 outputs one of the command signals _v2 to _{v6 instructing to appropriately select the boost taps t2 to t6 , and} the boost taps _{t2 to} t6 are output. A firing signal is given to a thyristor switch connected to one of _t6 . 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 81
1, a tap current detection signal corresponding to the newly selected tap is output, 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 810 outputs a signal v ₂ indicating that the tap should be switched to tap t ₂ while the transparent tap t ₁ is selected, the AND circuit A ₁₂
Since the AND of is established, the flip-flop circuit
_FF2 is set and the AND circuit establishes the AND of _A22 . Therefore, a rectangular wave signal is applied to the amplifier Am ₂ , 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 811, and the AND of the AND circuit _A32 is established. This AND circuit A ₃₂
The square wave signals of are supplied to the reset terminals of flip-flop circuits FF ₁ and FF ₃ corresponding to adjacent taps t ₁ and t ₃ via OR circuits OR ₁ and OR ₃ .
By resetting the flip-flop circuits FF ₁ and FF ₃ , the output signals of the AND circuits A ₂₁ and A ₂₃ become "0", and the inputs of the amplifiers Am ₁ and Am ₃ become "0".
become. Therefore, the supply of the firing signal to the thyristor switches S1 and S3 is prohibited, and the supply of the firing signal to the thyristor switch S1 is stopped (the firing signal is not originally supplied to the thyristor S3). At this time, thyristor switch S1
Of the two thyristor switches making up the thyristor switch, one thyristor to which a forward voltage is applied between its anode and cathode is in a conductive state; It becomes cut off when the polarity 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 other thyristor does not become conductive. In this way, the thyristor switch S1 enters the cut-off state, and the tap switching operation from tap t1 to tap t2 is completed.

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 801.
At this time, since the flip-flop circuit _FF0 is set, the AND of the AND circuit _A00 is established, and a rectangular wave signal is input to the through-tap amplifier _Am1 through the OR circuit _OR0 . 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 811, so the AND of the AND circuit _A30 is established, and the rectangular wave output signal of the AND circuit _A30 is passed through the OR circuits _OR2 to _OR6 to the flip-flop circuit FF2 _. ~ _FF6 reset terminals, respectively. As a result, the flip-flop circuit FF ₂ ~
All FFs ₆ are reset, and even if any of the taps _t2 to _t6 is selected, the supply of the ignition signal to the thyristor switch of the selected tap is stopped. In this way, the second set value
In the event of an overcurrent of less than I ₂ , switching to the through tap occurs unconditionally. In addition, if an overcurrent flows while energizing with 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 801 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.
If an overcurrent of I ₂ or more occurs at current time T ₁ , _the thyristor switch S ₁ becomes conductive as shown in FIG. The tap thyristor switch shuts it off. This delay time ΔT ₃ is a time corresponding to about 1/2 cycle of the normal power supply voltage. The second detection signal _e2 is input to the base of the transistor _Tr1 , so the transistor _Tr1 becomes conductive, and the relay _RY1
is excited. Contact RY ₁ a is therefore closed and contact RY ₁ b is opened. Since the disconnector 5 is now closed and the auxiliary contacts 52A and 52B are in the closed state,
When the contact RY ₁ a closes, the trip coil 53T is energized, which releases the mechanical lock of the sheath breaker 5, opens the main contacts 51A and 51B, and also opens the auxiliary contacts 52A and 52B. Also, when contact RY ₁ b opens, relay RY ₅ is deenergized, and contact RY ₅ a
and RY′ ₅ a opens. This opens the first automatic switch 6 as shown in FIG. 6D. Since there is a certain delay between the automatic switch's closed coil being deenergized and its contacts opening, the first automatic switch 6 opens a predetermined time later than the switch and disconnector 5.
The time ΔT ₄ from when an overcurrent occurs until the automatic switch 6 opens is approximately 3 cycles of the power supply. When the tap open detection circuit 805 detects that no tap current is flowing at the time when the breaker 5 is disconnected, the detection circuit 805 sends a signal to the delay circuit 80.
A signal is supplied to the transistor Tr ₃ via the transistor Tr 6 and the OR circuit ORa. This allows transistor Tr ₃
conducts, relay RY ₃ is energized and its contacts
RY ₃ a closes. At this time, contact RY ₂ b of relay RY ₂
is closed, so the relay RY ₄ is energized, the relay RY ₄ is self-held by the contact RY ₄ a, and the closing of the contact RY′ ₄ a causes the second automatic activation as shown in FIG. 6E. Switch 7 closes. Automatic switch 7
When the fault is closed, if the fault has not been removed, the fault current will flow to the fault point via the switch 7, and the current will be detected by the overcurrent relay (not shown) in the substation and will be activated by the overcurrent relay at the substation. is opened as shown in FIG. 6F. Since the second automatic switch 7 closes, the voltage of the control power supply drops extremely due to an accident, but the switch 7 is able to close the substation due to the action of the flywheel diode in its control circuit. remain closed for a sufficient period of time until it opens.

The operation after the fault is removed and the substation switch is turned on again is the same as the operation at the start of energization.

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. When turning on the power, first give a continuous ignition signal to the clear tap thyristor switch, then turn on the second automatic switch, and then
Since the second automatic switch is opened after the first automatic switch is turned on, the thyristor switch of the transparent tap is necessarily conductive. Therefore, no circuit voltage is applied to the thyristor switches of other taps. 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.

As mentioned above, if the first and second automatic switches are provided, the load side line can be disconnected by opening the first automatic switch in the event of an accident on the load side, so it is possible to protect the load. can. In addition, since the second automatic switch closes after the overcurrent is detected and the circuit breaker opens, if the fault has been resolved, power can be supplied to the load as is, and the fault has not been resolved. If there is no power supply, the substation's circuit breakers can be operated.

Incidentally, the first and second automatic switches or breakers may be used, but since they do not cut off a large current, a simple switch without a current cutoff function can be used. Furthermore, when the control power switch 11 is closed, it goes without saying that the tap open detection circuit is also reset by a reset signal from the power-on reset circuit.

In the above embodiment, a thyristor switch connected to a through-tap is selected as the thyristor switch that is continuously applied to the ignition signal before the breaker is turned on. A connected thyristor switch may also be selected.

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. Moreover, the first automatic switch 6 can be omitted.

As described above, according to the present invention, a direct switching type automatic voltage regulator using a thyristor switch is combined with a breaker and an automatic switch, and when the breaker is closed, the thyristor switch is switched on and off. A ignition signal is given to the thyristor switch to close the thyristor switch, and when an overcurrent is detected, a specific thyristor switch is made conductive to open the thyristor switch. Thyristor switches other than thyristor switches can be configured with small-capacity thyristors, and are static automatic voltage regulators that take advantage of the advantages of direct switching voltage regulators, such as not using a series transformer and making the device more compact. There is an advantage that the adjustment device can be provided at low cost. Furthermore, since conventional automatic voltage regulators do not have the function of cutting off the current, they cannot prevent accidents that occur on the line from spreading to other equipment, but in the present invention, the automatic voltage regulator itself Since it has a damping function, it can prevent accidents from spreading. In addition, since the second automatic switch is closed after the overcurrent is detected and the circuit breaker is opened, if the fault has been resolved, power can be supplied to the load as is, If the problem has not been resolved, the substation can be opened immediately.

[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 6F are diagrams showing the operation when the power is turned on when using the control device shown in the figure, and FIGS. 6A to 6F are diagrams showing the operation when an overcurrent is detected. 1... Substation, 2... Load, 3... Automatic voltage regulator, 4... Line, 5... Line breaker, 6... First
automatic switch, 7... second automatic switch, 8...
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 a first automatic switch 6 inserted into a circuit on the load side of the regulating transformer 11; a second automatic switch 7 that opens and closes between the power supply side terminal and the load side terminal of the first automatic switch ₆ ; When the overcurrent becomes less than (I ₂ ), the first overcurrent detection signal e ₁ is output, and when the overcurrent becomes more than the second set value (I ₂ ), the first overcurrent detection signal e ₁ and the second overcurrent are output. Equipped with an overcurrent detection circuit 801 that outputs a detection signal _e2 , the primary side and secondary side of the adjustment 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 the thyristor switch S ₁ , the second automatic switch 7 is closed, and the shutoff switch 5 is turned on and the first automatic switch 6 is closed. After closing the circuit in sequence, the second automatic switch 7 is opened, and the first overcurrent detection signal e ₁ is
When this occurs, 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 no voltage conversion is performed, and the second
When an overcurrent detection signal _e2 is generated, a control device 8 opens the shield breaker 5 and then sequentially opens the first automatic switch 6 and closes the second automatic switch 7. A static automatic voltage regulator characterized by comprising: