JPH0439089B2 - - 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.
There is no limit to the tap switching circuit 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 thyristor switches are connected to taps _t1 to _t4 of the regulating transformer, respectively.
An indirect switching type in which S ₁ to _{S 4} are connected and 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 has been known. Here, each thyristor switch has two
It consists of two thyristors SCR ₁ and SCR ₂ connected in antiparallel, and by making the thyristor switch of either tap conductive according to the line voltage, the tap is selected and the line voltage is adjusted to a predetermined value. It's becoming like that. 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 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, a thyristor is required to withstand the short circuit current when the load side is short-circuited. In the case of a large number of taps, it was inevitable that the equipment would become very expensive. Therefore, the present inventor first developed a static automatic thyristor that made it possible to use a thyristor with a relatively small current capacity by incorporating a cylindrical breaker into a direct switching type configuration and opening the cylindrical breaker in the event of a short-circuit accident. A voltage regulator was proposed. However, in the previously proposed device, when applied to a three-phase circuit, the
If a tap other than the designated tap is selected by mistake on a phase, an unbalanced output voltage will occur, which has a negative effect on the load.

As shown in Shozitsukō No. 53-35225,
A tap switching device has been proposed which locks an automatic operation command circuit when an extreme tap difference occurs, and then manually cancels the tap difference. However, with this configuration, if a tap difference occurs, the tap difference will remain as it is until the tap correction operation is performed, so if the tap correction operation is delayed, There was a risk that the transformer would burn out.

The purpose of the present invention is to eliminate the need to use a thyristor with a large current capacity, reduce loss, and, when misalignment occurs in the taps of each phase, to connect the power supply side line and load side line without going through a regulating transformer. It is an object of the present invention to provide a static type automatic voltage regulator for a three-phase circuit, which can be directly connected to the 3-phase circuit to prevent an adverse effect on the load.

The present invention provides a regulating transformer T, T connected to the line.
1, T, T2, and tap selection thyristor switches S1 to S connected to each tap of the regulating transformer.
This invention relates to a static automatic voltage regulator for a three-phase circuit, which is equipped with the following.

In the present invention, in order to achieve the above-mentioned object, a disconnector 5 inserted in the circuit on the power supply side than the regulating transformers T, T1, T, T2, and the regulating transformers T, T1, T, T2 A first automatic switch 6 inserted into the circuit on the load side, and a second automatic switch 6 that opens and closes between the power supply side terminal of the shield breaker 5 and the load side terminal of the first automatic switch 6. an automatic switch 7, a tap irregularity detection circuit 801 which detects the presence or absence of irregularities in the taps selected in each phase and outputs a tap irregularity detection signal e1 when the state in which the taps are irregular continues for a predetermined time; Using the output of the tap misalignment detection circuit as an input, when the tap misalignment detection signal e1 is output, the opening of the shim breaker 5, the opening of the first automatic switch 6, and the closing of the second automatic switch 7 are performed. A control device 8 is provided to perform the operations in sequence.

With the above configuration, when it is detected that the taps are not aligned for a predetermined period of time, the regulating transformer is disconnected from the power supply side circuit and the load side circuit,
Since the output of the power supply can be directly supplied to the load, power supply can be continued without adversely affecting the load, and power outages can be avoided.

Furthermore, as mentioned above, if the regulating transformer is disconnected from the power supply side circuit and the load side circuit when it is detected that the taps are not aligned for a predetermined period of time, burnout of the regulating transformer can be reliably prevented. can.

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. Further, 6 is a first automatic switch inserted into the circuit on the load side from the voltage regulator 3, and 7 is a switch for switching between the power side terminal of the shield 5 and the load side terminal of the first automatic switch 6. The second
This is an automatic switch. 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, it includes first and second regulating transformers T, T ₁ and T, T ₂ which are V-connected. Each regulating transformer consists of an autotransformer having multistage taps t ₁ to _{t 6} (the number of taps is arbitrary), and the taps t ₁ to t ₆ of each regulating transformer are equipped with thyristor switches S ₁ to _{S 6} , respectively.
is connected at one end. first regulating transformer T,
A tap that is directly connected to the primary and secondary sides of T ₁ and does not perform voltage conversion (hereinafter referred to as a "transparent tap"); one end on the t1 side and the second regulating transformer T, T ₂
One end of the transparent tap t ₁ side is the first automatic switch 6
output terminal 12a through contacts 61A and 61C of
and 12c, and the common connection point of the first and second regulating transformers T, T ₁ and T, T ₂ is connected to the output terminal 12b via the contact 61B of the first automatic switch 6. . A load side line is connected to each of these output terminals. Thyristor switches S ₁ to _{S 6} connected to the first regulating transformer T, T ₁
The other ends 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 connected to the input terminal 12A via the main contact 51A of the disconnector 5. There is. Thyristor switches _S1 to _S6 are also connected to the second regulating transformers T and _T2 .
The other ends are also 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 connected to the input terminal 12C via the main contact 51C of the disconnector 5. There is. The common connection point of the first and second regulating transformers is connected to the input terminal 12B via the main contact 51B of the disconnector 5.
Lines on the power supply side (substation side) are connected to A to 12C. Furthermore, the second automatic switch is configured to open and close between the power side terminals of the main contacts 51A, 51B and 51C of the breaker 5 and the load side terminals of the contacts 61A, 61B and 61C of the first automatic switch 6. Contacts 71A, 71B, and 71C of the switching path 7 are connected.

First and second regulating transformers T, T ₁ and T, T ₂
Auxiliary current transformers CT 1 to CT ₆ and CT _{′ 1} to CT′ ₆ are provided in lines connecting reactors L ₁ to _{L 6} and thyristor switches S _{1 to} S ₆ , respectively, provided in
These auxiliary current transformers allow the current flowing through the taps _t1 to _t6 of the respective regulating transformers to be detected.

The control device 8 controls 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 transformers T, T ₁ and T, T ₂ so as to maintain the line voltage at a predetermined value. In addition to the original control operations of the automatic voltage regulator, a control operation that continuously applies a firing signal to the thyristor switches connected to the open taps of each regulating transformer to close and open the mustard and disconnectors. Then, when an overcurrent is detected, the automatic circuit breaker 5 is opened, the first automatic switch 6 is opened, and when the tap opening is detected, the second automatic switch 7 is closed. control operation for controlling the switch and the first and second automatic switches, and when misalignment of the taps of each phase is detected, opening the shim breaker 5 and then opening the first automatic switch 6; It is configured to perform a control operation to close the second automatic switch 7 and to control the first and second automatic switches.

An example of the configuration of the control device 8 is shown in FIG. In the same figure, 801 is a tap irregularity detection circuit, and this circuit is a tap current detection circuit 8 which will be described later.
It receives an input signal from 11, 811' and outputs a tap misalignment detection signal _e1 when the taps selected in each phase remain misaligned for a predetermined period of time. The configuration of this tap misalignment detection circuit will be described later. The tap misalignment detection signal _e1 obtained from the tap misalignment detection circuit 801 is supplied to the base of the transistor _Tr1 whose emitter is grounded. The collector of the transistor Tr ₁ is connected to the DC power supply 8 through a parallel circuit with the coil of the relay RY ₁ and the diode D ₁ .
When the tap misalignment detection signal _e1 is generated, the transistor _Tr1
conducts, relay RY ₁ conducts, and relay RY ₁ is energized. 803 is a control power-on detection circuit that outputs one pulse signal when the switch 11 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 input to the base of the transistor Tr ₃ whose emitter is grounded through the OR circuit OR _a , and the output of the transistor Tr ₃
The collector of relay RY ₃ coil and diode
It is connected to the positive output terminal of the DC power supply 802 via a parallel circuit with _D3 . 805 is a detection signal when it is detected that the taps are open, that is, all of the taps _t1 to _t6 of the regulating transformers T, _T1 and T, _T2 are disconnected from the power supply and are not energized. This tap open detection circuit 805 receives an input signal from tap current detection circuits 811 and 811' (described later) through an OR circuit ORb, and the output signal is sent to a delay circuit 806.
and transistor Tr ₃ via the OR circuit ORa.
is supplied to the base.

Relay RY ₁ has normally open contact RY ₁ a and normally closed contact RY ₁ b
and relay RY ₂ has normally open contacts RY ₂ a, RY′ ₂
a and a normally closed contact RY ₂ b. Also relay
RY ₃ has normally open contacts RY ₃ a and RY' ₃ a, and the coil of relay RY ₄ is connected to DC power supply 802 via one normally open contact RY ₃ a and the above-mentioned normally closed contact RY ₂ b. ing. Relay RY ₄ has normally open contacts RY ₄ a, RY′ ₄ a
and one normally open contact RY ₄ a is the above normally open contact.
Connected in parallel with RY ₃ a. Also relay RY ₂
The contact RY ₂ a of the relay RY ₁ and the contact RY ₁ b of the relay RY 1 are connected in series, and the coil of the relay RY ₅ is connected to the series power supply 802 via these contacts. The relay RY ₅ has normally open contacts RY ₅ a and RY' ₅ a, and 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 a full-wave rectifier Rec ₁ to which an AC voltage of 100V is input from the control power transformer 9 shown in FIG. 2 through the control power switch 11.
and connect the above contact between the output terminals of this full-wave rectifier.
A series circuit of RY' ₂ a, the coil of relay RY ₆ , and normally closed contact RY ₇ b of relay RY ₇ , and a series circuit of diode D ₄ , resistor R ₁ , and capacitor C ₁ are connected in parallel. Coil of relay RY ₆ and normally closed contact RY ₇
A series circuit of a coil of relay RY ₇ and a normally open contact RY ₇ a of relay RY ₇ is connected in parallel to both ends of the series circuit with b, and a normally open contact RY is connected to the connection point of resistor R ₁ and capacitor C ₁ . ₁ One end of a is connected.

In the example shown in FIG. 4, the line breaker 5 is provided with auxiliary contacts 52x and 52y that open and close in conjunction with these main contacts in addition to main contacts 51A, 51B, and 51C that open and close the three-phase lines, respectively. , auxiliary contact 52
One end of x and 52y is commonly connected to the negative output terminal of the rectifier Rec ₁ . The other end of the auxiliary contact 52x is connected to the other end of the normally open contact RY ₁ a via a trip coil 53T, and the other end of the auxiliary contact 52y is connected to the coil of the relay RY ₇ and the contact RY ₇ a.
connected to the connection point. 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 .
A _smoothing capacitor _C3 is connected in parallel to the output terminal of the rectifier _Rec2 . Further, between the input terminals a and b of the second automatic switch 7, the output of the full-wave rectifier Rec ₃ to which the output of the control power transformer 9 is similarly input via the switch 11 is connected to a contact RY' ₄ a. 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, 61B, and 61C 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 results in contact points Xb and X′b
opens and relay Mc is deenergized. In this state, the excitation current of the closed coil CC is limited by the resistor _R2 , and the current of the closed coil CC is reduced to the holding current required to keep the switch in the closed state. Further, the excitation current of relay X is also limited to the holding current by resistors R ₃ and R ₄ . Input terminal a,
When the voltage across b is removed, the closed coil CC
contacts 61A, 61B and 61C are deenergized.
opens. The operation of the second automatic switch 7 is similar to that described above, except that the opening operation is delayed by the flywheel diode _D5 .

In FIG. 4, A ₁₁ to A ₁₆ , A ₂₁ to A ₂₆ and A ₃₁ to
A ₃₆ is a 2-input AND circuit, OR ₁ to OR ₆ are OR circuits,
FF ₁ ~ FF ₆ are flip-flop circuits, Am ₁ ~ _{Am 6}
is an amplifier consisting of a transistor, P ₁ to _{P 6} is composed 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} , a pulse-shaped ignition signal e is generated. A pulse output circuit that simultaneously outputs _g2 and e _g2 , and 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 control circuit I is configured to turn on and off the thyristors S ₁ to _{S 6} of the devices T and T ₁ . In more detail, AND circuit A ₁₁
A rectangular pulse signal e ₃ obtained from the signal source circuit 808 is input to one input terminal of each of _{~A 16} and A ₂₁ to _{A 26} , and the other input terminal of each AND circuit A ₁₁ to _{A 16} is input. Voltage adjustment relay 809a
Outputs v 1 to _{v 6 of} the tap switching command signal generation circuit 810 controlled by the reversible binary counter 809b
is entered. Tap switching command signal generation circuit 810 is comprised of, for example, a decoder, 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 809a. 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 , and the output of the AND circuit A ₂₂ ~
The output of _A26 is input to amplifiers _Am2 to _Am6 , respectively. The outputs of amplifiers Am ₂ - Am ₆ are respectively connected to pulse output circuits P ₂ - _{P 6} and filter circuits F ₂ - _{F 6}
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 AND circuit A ₂₁ is supplied to one input terminal of AND circuit A ₃₁ , and the outputs of AND circuits A ₂₂ to _{A 26} are supplied to one input terminal of AND circuits A ₃₂ to _{A 36} , respectively. 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 is
The outputs of the auxiliary current transformers CT ₁ to _{CT 6} provided for the taps t ₁ to t ₆ of the first regulating transformers T and T 1 are respectively rectified by the rectifier _{Rec 4 and} regulated by the constant voltage diode ZD. It inputs voltage-converted signals w ₁ to _{w 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, and when one of the taps is selected, that tap is When a current flows through the tap, the tap current detection circuit 811 outputs a tap current detection signal corresponding to the selected tap. AND circuit A ₃₁
The output of is input to the OR circuit OR ₂ , and the AND circuit
The output of _A32 is input to OR circuits _OR1 and _OR3 . The output of AND circuit A ₃₃ is OR circuit OR ₂ and
The output _{of AND circuit A34 is} input to OR circuits _OR3 and _OR5 . In addition, the output of AND circuit A ₃₅ is input to OR circuits OR ₄ and OR ₆ ,
The output of AND circuit _A36 is input to OR circuit _OR5 . The outputs of the OR circuits OR ₁ to _{OR 6} are supplied to the reset terminals of the flip-flop circuits FF ₁ to _{FF 6} , respectively, and when a signal in the state of "1" is output from each of the OR circuits OR ₁ to OR ₆ , the flip-flop circuits FF ₁ The output of ~ _FF6 becomes "0", and the outputs of AND circuits _A21 to _A26 become "0". In order to reset the control circuit when the switch 11 is turned on, a power-on reset circuit 812 is provided, and a reset signal e _r obtained from this circuit is provided.
is a reversible binary counter 809b, a tap switching command signal generation circuit 810, and a tap open detection circuit 80.
5, the circuit breaker opening command generation circuit 801, and one input terminal of OR circuits _OR1 to _OR6 .

In exactly the same way, a control circuit is provided for turning on and off the thyristor switches S ₁ to _{S 6} of the second regulating transformers T, T ₂ , and this control circuit is connected to the tap switching command signals v ₁ to v ₆ and the signal source. The pulse signal e ₃ of the circuit 808, the reset signal e _r obtained from the power-on reset circuit 812, and the second regulating transformer T, T ₂
Tap current detection circuit 81 that detects the tap current of
The thyristor switches S1 _{to S6} of the second regulating transformers T and T2 are turned on and off by inputting the tap current detection signals _u1 ' to _u'6 obtained from the transformers T _{and T2} . Here, the tap current detection circuit 811' detects the tap current of the second regulating transformer T, _{T2 .}
Signals w' ₁ to w' ₆ obtained by rectifying the output of CT' ₆ and making it constant voltage with a constant voltage diode ZD are input to correspond to taps t ₁ to _{t 6} of second regulating transformers T and T ₂ , respectively. It outputs tap current detection signals u' ₁ to u' ₆ to the output terminals, and is similar to the tap current detection circuit 811 described above.

Tap current detection signals u ₁ -u ₆ and u' ₁ - obtained from the tap current detection circuits 811 and 811'
u' ₆ is input to the tap irregularity detection circuit 801, and is also input to the tap open detection circuit 805 through the OR circuit ORb. As shown in FIG. 5, for example, the tap misalignment detection circuit 801 generates exclusive OR circuits EX ₁ to EX ₆ , an OR circuit ORx whose output is the input of these exclusive OR circuits, and a reference clock signal e _c . It consists of a reference clock generation circuit _OS1 , an AND circuit _AND1 which receives the reference clock signal _ec and the output of the OR circuit ORx, and a preset counter PC which counts the pulses obtained from the AND circuit _AND1 . Exclusive OR circuit EX ₁ ~ _{EX 6}
are the tap current detection signals (u ₁ , u′ ₁ ),
(u ₂ , u′ ₂ ), ... (u ₆ , u′ ₆ ) are input.
In this tap irregularity detection circuit, each exclusive OR circuit outputs a signal of "1" only when the levels of the two input signals are different, and outputs a signal of "0" when the two input signals are equal. Therefore the first and second regulating transformers T,
If there is a mismatch between the taps selected by T ₁ and T, T ₂ , the output of one of the exclusive OR circuits becomes "1", and the output of the OR circuit ORx becomes "1".
become. When the output of the OR circuit ORx becomes "1",
AND circuit every time the reference clock signal e _c is generated.
AND ₁ is established and a pulse of "1" is generated at the output terminal of AND circuit AND ₁ . The preset counter PC counts the "1" output signal pulses of this AND circuit AND ₁ , and detects tap misalignment when the counted value reaches a preset value, that is, when the tap misalignment continues for a predetermined period of time. Outputs signal e ₁ . Note that the count value of the preset counter PC can be set arbitrarily.

On the other hand, the tap open detection circuit 805 is connected to the sixth tap, for example.
As shown in the figure, there are six input terminals h1 _{, h2} to which tap current detection signals _u1 to _u6 or _u'1 to _u'6 are input.
...a NOR circuit with _h6 and a flip-flop circuit whose set input is the output of this NOR circuit.
FF ₀ , and when the firing signals of all thyristor switches are lost and all the input signals of the NOR circuit NOR become "0", the "1" state signal output from the NOR circuit NOR. At the rising edge, the flip-flop circuit FF ₀ is set, and the tap open detection signal e ₂ in the state of "1" is sent to its positive logic output terminal Q.
I'm starting to get more.

Furthermore, AND circuits A ₁₁ to A ₁₆ ……A ₃₁ to A ₃₆ , OR circuits OR ₁ to OR ₆ , flip-flop circuits FF ₁ to FF ₆
Electric power for operating each part of the control circuit is provided by a constant voltage power supply circuit 814 to which the output of the control power transformer 9 is input via the control power switch 11.

Next, the operation of the above embodiment will be explained. When the control power switch 11 is closed as shown in FIG. 7A at the start of energization, a reset signal e _r (see FIG. 7B) is output from the power-on reset circuit 812, and this reset signal activates the tap switching command signal generation circuit. 8
10. Control circuit and flip-flop circuit
FF ₁ to _{FF 6} , the breaker open command generation circuit 801 and the tap open detection circuit 805 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 _A21 outputs a rectangular wave signal, and this signal is input to the amplifier _Am1 . This allows the thyristor switch of S ₁ to pass through the thyristor switch of T ₁ .
Ignition signals eg ₁ and eg ₂ are applied to SCR ₁ and SCR ₂ (see Figure 7C)
is given, and the preparation for conduction of thyristor switch _S1 is completed. On the other hand, turning on of the control power switch 11 is detected by the control power turning on detection circuit 803,
One pulse-like signal is applied from this detection circuit to the transistor Tr ₃ through the OR circuit ORa. This makes transistor Tr ₃ conductive and relay RY ₃
is energized and its contact RY ₃ a closes. Contact RY ₃
Relay RY ₄ is energized by the closing of a, and its contacts
Self-maintained by RY ₄ a. At this time, the contact
Since RY' ₄ a is also closed, the automatic switch 7 is closed as shown in FIG. 7D. The pulsed output of the above-mentioned closing detection circuit 803 is also supplied to the transistor Tr ₂ through the delay circuit 804, so that after a certain period of time △T ₁ after the switch 11 is turned on, the transistor Tr ₂ is output, which corresponds to the width of the output pulse of the closing detection circuit 803. relay RY ₂ operates for a short time. When contact RY ₂ a of relay RY ₂ closes, relay RY ₅ is energized and its contact RY′ ₅ a closes, and contact RY′ ₂
By closing a, the sheath breaker 5 is closed. Further contacts
By closing RY ₅ a, relay RY ₅ is self-holding,
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 due to flywheel diode D ₅ , closed coil CC
Since the deenergization of the automatic switch 6 is delayed, the automatic switch 7 opens after a certain delay time ΔT ₂ has elapsed after the automatic switch 6 is closed, as shown in FIG. 7D. At the same time as the automatic switch 7 opens, as shown in FIG. 7F, the thyristor switch _S1 of the through-tap, to which the ignition signal has already been applied, becomes conductive and current flows through the through-tap _t1 . In this way, since thyristor switch _S1 immediately conducts when power starts,
No line voltage is applied to the thyristor switches _S2 to _S6 , and only a small voltage approximately corresponding to the tap-to-tap voltage is applied to the thyristor of each thyristor switch. Here, the delay time △T ₁
and ΔT ₂ are set to, for example, approximately ΔT ₁ =ΔT ₂ =1 [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
According to the operation of step 9a, 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 8
11,811' outputs a tap current detection signal corresponding to the newly selected tap, and this signal eliminates the firing signal applied to the thyristor switch of the previously selected tap. 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 transparent tap t ₁ is selected and the tap switching command signal generation circuit 810 outputs a signal v ₂ indicating that the tap should be switched to the tap t ₂ ,
Since the AND of AND circuit A ₁₂ is established, flip-flop circuit FF ₂ is set, and AND circuit A ₂₂
The AND is established. 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 is generated from the tap current detection circuits 811 and 811'.
u ₂ is output, and the AND of AND circuit A ₃₂ is established. The square wave signal of this AND circuit A ₃₂ is an OR circuit
It is supplied via OR ₁ and OR ₃ to the reset terminals of flip-flop circuits FF ₁ and FF ₃ corresponding to adjacent taps t ₁ and t ₃ . flip-flop circuit
By resetting FF ₁ and FF ₃ , the output signals of AND circuits A ₂₁ and A ₂₃ become "0", and the amplifier
The inputs of Am ₁ and Am ₃ become "0". Therefore, the supply of the ignition signal to the thyristor switches S ₁ and S ₃ is stopped, and the thyristor switches S ₁ and S ₃ are cut off when the anode potential of each thyristor becomes negative with respect to the cathode.

While energized by a tap, the first and second regulating transformers T,
The thyristor switches of different taps _T1, T, and _T2 are fired, and if this state continues, the taps will be in a state of misalignment. At this time, the tap misalignment detection circuit 801 generates a tap misalignment detection signal by the above-described operation.
Outputs e ₁ and turns on transistor Tr ₁ . This energizes relay RY ₁ , so the contact
RY ₁ a closes and contact RY ₁ b opens. Therefore, as shown in FIGS. 8A and 8B, if tap misalignment occurs at time _T1 , after the settling time △ _T3 determined by the count value of the preset counter PC has elapsed, the tap disconnector 5 and the automatic Switch 6 opens.

When the shield breaker 5 opens, no load current flows, so the tap open detection circuit 805 outputs a high level tap open detection signal _e2 . This detection signal e ₂
is applied to the transistor Tr ₃ through the delay circuit 806 and the OR circuit ORa.
Tr ₃ becomes conductive and relay RY ₃ is energized. This closes the contact RY ₃ a, so that the relay RY ₄ is energized, and the automatic switch 7 is turned on by the same operation as the above-mentioned operation when the power is turned on. Here, the delay time ΔT ₄ of the delay circuit 806 is set to about 0.5 [sec]. By turning on the automatic switch 7, power supply to the load is restarted.

In the above embodiment, two regulating transformers are V-connected to form a three-phase automatic voltage regulating device.
The present invention can be similarly applied to the case where an automatic voltage regulator is constructed by three-phase wiring of three regulating transformers.

As described above, according to the present invention, since the regulating transformer is disconnected from the power supply by opening the sheath disconnector when the taps are not aligned, it is possible to prevent burnout of the regulating transformer. In addition, in the present invention, when misalignment of the taps occurs, the automatic switch is opened after opening and the automatic switch is closed to continue energizing the load, thereby protecting the load from the negative balance voltage and making it useless. This has the advantage that power outages can be prevented, and the regulating transformer can be properly protected.

[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. 5 and 6 are respectively A connection diagram showing an example of a tap misalignment detection circuit and an open tap detection circuit used in the control device shown in FIG. 4, and FIGS. 7A to F are diagrams showing operations when the power is turned on when using the control device shown in FIG. 4. , and FIGS. 8A to 8D are diagrams illustrating the operation when a short circuit occurs between taps when the control device of FIG. 4 is used. 1... Substation, 2... Load, 3... Automatic voltage regulator, 5... Line breaker, 6... First automatic switch, 7... Second automatic switch, 8... Control device,
801... Tap misalignment detection circuit, 807... Edge breaker control circuit, 811... Tap current detection circuit, AND ₁ , A ₁ to A ₁₅ , A ₁₁ to A ₁₆ , A ₂₁ to A ₂₆ ,
A ₃₁ to A ₃₆ ...AND circuit, OR ₁ to OR ₆ , ORx,
ORy, ORa...OR circuit, FF ₀ , FF ₁ ~ FF ₆ ...
Flip-flop circuit, _S1 to _S6 ...Thyristor switch, _EX1 to _EX6 ...Exclusive OR circuit.

Claims (1)

[Claims] 1. Adjustment transformers T, T1, T, connected to the line.
In the static automatic voltage regulator for a three-phase circuit, the static automatic voltage regulator includes a voltage regulator T2 and tap selection thyristor switches S1 to S6 connected to each tap of the regulator transformer, wherein the regulator transformer T, T1, T, T2 a first automatic switch 6 inserted in a circuit closer to the load than the regulating transformers T, T1, T, T2; A second switch that opens and closes between the power supply side terminal of the disconnector 5 and the load side terminal of the first automatic switch 6.
an automatic switch 7, and a tap irregularity detection circuit 801 that detects the presence or absence of misalignment of the taps selected in each phase and outputs a tap irregularity detection signal e1 when the state where the taps are irregular continues for a predetermined period of time; With the output of the tap misalignment detection circuit as an input, when the tap misalignment detection signal e1 is output, the shingle breaker 5 is opened, the first automatic switch 6 is opened, and the second automatic switch is opened. 7. A static automatic voltage regulator for a three-phase circuit, comprising a control device 8 for sequentially closing and closing circuits in a three-phase circuit.