JP7312099B2 - on-load tap changer - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-load tap changer that switches taps of a transformer with a changeover switch.

A so-called indirect switching type voltage regulator consists of a series transformer whose secondary winding is connected in series with the distribution line, and a primary winding whose primary winding is connected in parallel with the distribution line and the secondary winding is provided with multiple taps. and a tap changer for switching the plurality of taps for connection to the primary winding of the series transformer.

The tap changer consists of a changeover switch for switching the taps connected to the primary winding of the series transformer, and a current limiting element such as a current limiting resistor that limits the bracing current flowing between the taps in the process of switching the taps. , and a rectifying switch for connecting and disconnecting between the taps of the current limiting element. By turning these switches on and off in a predetermined sequence, the tap changer switches the magnitude and polarity of the regulated voltage applied from the regulating transformer to the primary winding of the series transformer.

The changeover switch has one end connected to one of the taps and the other end to one of the outputs of the tap changer. In other words, the potentials at one end and the other end of the change-over switch are usually different depending on the change-over switch. For example, if the change-over switch is a thyristor, the gate signal for turning on the change-over switch is a signal with one end or the other end of the change-over switch as a reference potential. Therefore, the power source of the circuit that generates the gate signal is basically insulated for each thyristor.

On the other hand, Patent Document 1 describes a tap changer using a solid state contactor including three pairs of thyristors connected in anti-parallel and one control power supply section and control section. One tap-changing switch provided in this tap-changing device is configured for three phases by one solid-state contactor including three thyristor pairs. With this configuration, 5 solid state contactors are used (excluding the current limiting resistor switch) to switch 4 taps per phase for 3 phases for 7 tap positions.

The solid-state contactor described above is a general-purpose product, and can be used under the condition that the cathodes of all built-in thyristors are at different potentials. It is therefore evident that the control power supply actually contains six power supplies that are isolated from each other.

Japanese Unexamined Patent Application Publication No. 2014-115770

However, even the tap changer with seven tap positions described in Patent Document 1 requires five power supply sections, which is the same number as the solid state contactors, and strictly speaking, 30 power supplies are required (current limiting resistors (except instrument switches). To increase the number of tap positions to say thirteen, the number of power supplies must be increased to eight. In addition, this solid-state contactor is a commercial product and has many restrictions. For example, in order to secure the minimum operating voltage, there is a problem that a special tap other than the switching tap must be provided on the transformer.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and its object is to provide an on-load tap changer capable of reducing the number of power sources for turning on the tap changeover switches. be.

An on-load tap changer according to an aspect of the present invention includes a plurality of changeover switches for switching a plurality of taps of a winding of a tapped transformer, and the on-load taps that drive the plurality of changeover switches to ON. A changeover switch, wherein one end of each of the plurality of changeover switches is connected to one of the plurality of taps, and some of the changeover switches and other changeover switches Two insulated first power sources, the other ends of which are connected to each other, for separately supplying an ON signal to each of the partial changeover switch and the other changeover switch; and a first connection circuit for alternatively connecting the switch to which the signal is supplied.

In this aspect, one end of each of the plurality of changeover switches for switching the plurality of taps of the winding of the tapped transformer is connected to any one of the plurality of taps. Some of the changeover switches are connected to each other at the other ends so as to be one output of the device itself, and the ON signal is selectively output from the first power supply of the insulation type through the first connection circuit. supplied. The other change-over switches are connected at the other ends to serve as other outputs of the device themselves, and are selectively supplied with ON signals from other first power supplies via other first connection circuits. Thereby, when one of the change-over switches and one of the other change-over switches are driven to ON, one tap is connected to one output, and the tap which is the same as or different from the one tap is connected. is connected to the other output. Also, all the change-over switches related to one winding are supplied with an ON signal from either of the two power sources.

In the on-load tap changer according to one aspect of the present invention, each first connection circuit includes a first isolation circuit between one end of the corresponding first power supply and the control terminal of the corresponding changeover switch. The other end of each first power supply is connected to the other end of a selector switch to which an ON signal is supplied from each first power supply. ing.

In this aspect, when the first switching element included in the first connection circuit is turned on in response to the first signal input through the first isolation circuit, the corresponding one end of the first power supply and the changeover switch is connected to the control terminal of The other end of the first power supply is connected to the other end of the corresponding selector switch. Thereby, the changeover switch can be turned on by the first signal insulated from the first power supply.

An on-load tap changer according to one aspect of the present invention includes an interlock circuit for each first connection circuit that exclusively outputs a first signal input to each first connection circuit.

In this aspect, while one first signal is being output from the interlock circuit to one first connection circuit, other first signals are prohibited from being output.

In the on-load tap changer according to one aspect of the present invention, each changeover switch includes a bidirectionally conductive triac, and the ON signal is a trigger signal supplied to the triac included in each changeover switch.

In this aspect, since the triac included in the change-over switch is bidirectionally conducted by the trigger signal supplied from the first power supply through the first connection circuit, the configuration of the change-over switch and the drive circuit for the change-over switch is Simplified.

In an on-load tap changer according to an aspect of the present invention, each changeover switch includes a first thyristor whose anode is connected to one of the taps and a second thyristor connected in anti-parallel to the first thyristor. wherein the ON signal is a trigger signal supplied to a first thyristor included in each changeover switch, and a trigger signal is separately supplied to a second thyristor included in each of the one changeover switch and the other changeover switch. and a second connection circuit for alternatively connecting each of the second power supplies and the second thyristors to which trigger signals are supplied from the respective second power supplies.

In this aspect, each selector switch includes a first thyristor and a second thyristor that are connected in anti-parallel. The first thyristors whose cathodes are connected to each other are alternatively supplied with a trigger signal from the corresponding first power supply via the corresponding first connection circuit. Anodes of the second thyristors included in some change-over switches are connected to each other, and a trigger signal is alternatively supplied from one second power source of an insulating type via one second connection circuit. The anodes of the second thyristors included in the other selector switches are connected to each other, and trigger signals are alternatively supplied from the other second power sources via the other second connection circuits. As a result, the first thyristor and the second thyristor included in one of the change-over switches and the first thyristor and the second thyristor included in one of the other change-over switches are turned on. If so, one tap is connected to one output and the same or different tap is connected to the other output. All the first thyristors and second thyristors associated with one winding are supplied with a trigger signal from any one of the four power sources.

In the on-load tap changer according to one aspect of the present invention, each second connection circuit has, between one end of the corresponding second power supply and the gate of the second thyristor included in the corresponding changeover switch, It has a second switching element that is turned on in response to a second signal input through the second isolation circuit, and the second thyristor included in the corresponding other end of the second power supply and the corresponding changeover switch. A third switching element is provided between the cathode and the third switching element which is turned on in response to a third signal input via a third insulating circuit.

In this aspect, the second switching element and the third switching element included in the second connection circuit respond to the second signal and the third signal input via the second isolation circuit and the third isolation circuit, respectively. When turned on, one end and the other end of the second power supply are connected to the gate and cathode of the second thyristor, respectively. Thereby, the second thyristor included in the changeover switch can be turned on by the second signal and the third signal insulated from the second power supply. Further, while the second thyristor is off, the tap to which the anode of the second thyristor is connected is separated from the second power supply, thereby preventing a short circuit between the taps.

According to the present invention, it is possible to reduce the number of power supplies for turning on the changeover switch of the tap.

1 is a block diagram showing a configuration example of a voltage regulator including an on-load tap changer according to Embodiment 1; FIG. 4 is a chart showing the relationship between the tap position and the changeover switch to be turned on for the OU phase. FIG. 4 is an explanatory diagram showing the relationship between the voltage induced in the secondary winding of the regulating transformer and the voltage supplied to the primary winding of the series transformer; FIG. 4 is a circuit diagram showing a first configuration example of each change-over switch for switching the taps of the secondary windings and the driving section in the tap changer according to the first embodiment; FIG. 4 is a circuit diagram showing a first configuration example of each change-over switch for switching the taps of the secondary windings and the driving section in the tap changer according to the first embodiment; FIG. 11 is a circuit diagram showing a configuration example of a first power supply used in a drive section of a tap changer according to Modification 1; FIG. 10 is a circuit diagram showing a configuration example of an interlock circuit used in the driving section of the tap changer according to Embodiment 2; FIG. 11 is a circuit diagram showing a second configuration example of each change-over switch for switching the taps of the secondary windings and the driving section in the tap changer according to Embodiment 3; FIG. 11 is a circuit diagram showing a second configuration example of each change-over switch for switching the taps of the secondary windings and the driving section in the tap changer according to Embodiment 3; FIG. 11 is a circuit diagram showing a configuration example of a driver circuit used in a driving section of a tap changer according to modification 2; FIG. 11 is a circuit diagram showing a configuration example of a driver circuit used in a driving section of a tap changer according to Modification 3;

Hereinafter, the present invention will be described in detail based on the drawings showing its embodiments.
(Embodiment 1)
FIG. 1 is a block diagram showing a configuration example of a voltage regulator including an on-load tap changer according to Embodiment 1. FIG. A voltage regulator (SVR=Step Voltage Regulator) 100 adjusts the U-phase, V-phase, and W-phase AC voltages supplied from the power supply on the left side of the page, and connects the distribution lines 1u, 1v, and 1w to the loads on the right side of the page. u-phase, v-phase, and w-phase AC voltages are distributed through the

A voltage regulator 100 includes a series transformer 1 in which secondary windings 112, 122, and 132 are connected in series to distribution lines 1u, 1v, and 1w, respectively, and primary windings 211 and 221 to distribution lines 1u, 1v, and 1w. , 231 are Δ-connected, and a regulating transformer 2 (corresponding to a tapped transformer). The voltage regulator 100 further includes on-load tap changers (hereinafter referred to as simply called a tap changer) 3. The tap changer 3 and the regulating transformer 2 constitute an on-load tap-changing transformer 200 .

In series transformer 1, primary windings 111, 121, and 131 correspond to secondary windings 112, 122, and 132, respectively. The primary windings 111, 121, 131 are delta-connected. The terminals of the primary windings 111, 121, 131 corresponding to the load-side terminals of the secondary windings 112, 122, 132 are u1, v1, w1. Further, the terminals of the primary windings 111, 121, 131 corresponding to the terminals on the power supply side of the secondary windings 112, 122, 132 are u2, v2, w2.

In the regulating transformer 2, the primary winding 211 is connected between the distribution lines 1u and 1v, the primary winding 221 is connected between the distribution lines 1v and 1w, and the primary winding 231 is connected between the distribution lines 1w and 1u. Secondary windings 212, 222, 232 correspond to the primary windings 211, 221, 231, respectively.

Each of the secondary windings 212, 222, 232 has taps t1 and t4 brought out from one end and the other, and intermediate taps t2 and t3 brought out from between one end and the other. Each of the secondary windings 212, 222, 232 is connected to the terminals u2, v2, w2 on the primary side of the series transformer 1 via the tap changer 3 and the terminals v1, w1, w1, w1, u1 and any other one is connected to ground as a neutral point N. That is, the secondary windings 212 , 222 , 232 of the regulating transformer 2 are Y-connected through the tap changer 3 .

In order to measure the voltage applied to the primary windings 211, 221, 231 of the regulating transformer 2, the distribution lines 1u, 1v, 1w are V-connected to the measuring transformers PT1, PT2. That is, the primary winding of the measuring transformer PT1 is connected between the distribution lines 1u and 1v, and the primary winding of the measuring transformer PT2 is connected between the distribution lines 1v and 1w. For example, assuming that the secondary windings of the measuring transformers PT1 and PT2 are a Δ-connected three-phase balanced circuit, the control unit 31, which will be described later, obtains the measured voltages for the three phases, so that the primary windings 211 and 221 , 231 is detected.

The tap changer 3 includes eight changeover switches ThA_U, ThB_U, ThC_U, ThD_U, Th1_U, Th2_U, Th3_U, Th4_U for switching the taps t1 to t4 of the secondary winding 212 of the regulating transformer 2, and the secondary winding 8 selector switches ThA_V, ThB_V, ThC_V, ThD_V, Th1_V, Th2_V, Th3_V, Th4_V for switching the taps t1 to t4 of the secondary winding 232, and eight selector switches ThA_W for switching the taps t1 to t4 of the secondary winding 232. , ThB_W, ThC_W, ThD_W, Th1_W, Th2_W, Th3_W, Th4_W.

The configuration of the tap changer is not limited to that shown in FIG. may

The tap changer 3 further includes a control section 31 for controlling switching of each changeover switch, and a drive section 32 for driving each changeover switch to ON based on a drive signal from the control section 31 . The control unit 31 is connected to the secondary windings of the measuring transformers PT1 and PT2 and the secondary windings of the measuring transformers PT3, PT4 and PT5, which will be described later. The connection between the control unit 31 and each measuring transformer and the connection between the drive unit 32 and each changeover switch are omitted from the drawing.

The control unit 31 has a CPU (Central Processing Unit) (not shown), and controls voltage adjustment according to a control program stored in advance in a ROM (Read Only Memory). Temporarily generated information is stored in RAM (Random Access Memory).

The tap t1 of the secondary winding 212 is connected to one end of the changeover switches ThA_U and Th1_U through a protective fuse (not shown; the same applies hereinafter), and the tap t2 is connected through the fuse to one end of the changeover switches ThB_U and Th2_U. , the tap t3 is connected via a fuse to one ends of the change-over switches ThC_U and Th3_U, and the tap t4 is connected to one end of the change-over switches ThD_U and Th4_U. The other ends of the selector switches ThA_U, ThB_U, ThC_U, and ThD_U are connected to the neutral point N. The other ends of the selector switches Th1_U, Th2_U, Th3_U, and Th4_U are connected to terminals u2 and v1 on the primary side of the series transformer 1 via a connection line 3u. The connection line 3u is for outputting a U-phase AC voltage from the tap changer 3, the phase of which is denoted by OU.

The tap t1 of the secondary winding 222 is connected via a fuse to one end of the changeover switches ThA_V and Th1_V, the tap t2 is connected via a fuse to one end of the changeover switches ThB_V and Th2_V, and the tap t3 is connected to the fuse. , and the tap t4 is connected to one end of the changeover switches ThD_V and Th4_V. The other ends of the selector switches ThA_V, ThB_V, ThC_V, and ThD_V are connected to the neutral point N. The other ends of the selector switches Th1_V, Th2_V, Th3_V, and Th4_V are connected to terminals v2 and w1 on the primary side of the series transformer 1 via a connection line 3v. The connection line 3v is for outputting a V-phase AC voltage from the tap changer 3, the phase of which is denoted by OV.

The tap t1 of the secondary winding 232 is connected via a fuse to one end of the changeover switches ThA_W and Th1_W, the tap t2 is connected via a fuse to one end of the changeover switches ThB_W and Th2_W, and the tap t3 is connected to the fuse. , and the tap t4 is connected to one end of the changeover switches ThD_W and Th4_W. The other ends of the switches ThA_W, ThB_W, ThC_W, and ThD_W are connected to the neutral point N. The other ends of the selector switches Th1_W, Th2_W, Th3_W, and Th4_W are connected to terminals w2 and u1 on the primary side of the series transformer 1 via a connection line 3w. The connection line 3w is for outputting a W-phase AC voltage from the tap changer 3, and its phase is represented as OW.

Between the connection lines 3u and 3v, a series circuit of a current limiting resistor R_UV and a shorting switch ThS_UV and an electromagnetic contactor MC_UV are connected in parallel. Between the connection lines 3v and 3w, a series circuit of a current limiting resistor R_VW and a straightening switch ThS_VW and an electromagnetic contactor MC_VW are connected in parallel.

The break-in switch ThS_UV is a current-limiting resistor between the taps in order to break-through between the taps via the current-limiting resistor R_UV in the process of switching the taps t1 to t4 of the secondary winding 212 or 222. It is for connecting and disconnecting the device R_UV. In the process of switching the taps t1 to t4 of the secondary winding 222 or 232, the break-in switch ThS_VW is a current-limiting resistor between the taps in order to break-through between the taps via the current-limiting resistor R_VW. It is for connecting and disconnecting the device R_VW. The magnetic contactors MC_UV and MC_VW are connected to the terminals u1 and u2 on the primary side of the series transformer 1 when an overcurrent is detected and all the changeover switches are turned off, or when the operation of the tap changer 3 is stopped. , terminals v1 and v2, and terminals w1 and w2 are braided to prevent an open state.

Measuring transformers PT3, PT4 and PT5 are Y-connected to the connection lines 3u, 3v and 3w in order to measure the voltages of the secondary windings 212, 222 and 232 output from the switched taps. That is, the primary winding of the measuring transformer PT3 is connected between the connecting line 3u and the ground, and the primary winding of the measuring transformer PT4 is connected between the connecting line 3v and the ground. A primary winding of a measuring transformer PT5 is connected between the connection line 3w and ground. The secondary windings of the measuring transformers PT3, PT4, and PT5 are Y-connected and connected to the controller 31. FIG. By the control unit 31 acquiring the measured voltages for the three phases OU, OV, and OW from the secondary windings of the measuring transformers PT3, PT4, and PT5, the tap-switched secondary windings 212, 222, and 232 Voltage is detected.

Next, a combination of switches to be turned on will be described. FIG. 2 is a chart showing the relationship between the tap position and the changeover switch to be turned on for the OU phase. For other OV phases and OW phases, similar charts with U replaced by V and W are shown. Although the OU phase will be mainly described below as an example, the same explanation holds for the OV and OW phases.

There are 13 combinations of change-over switches, and these combinations are represented by tap positions from tap 1 to tap 13. For example, when the tap position is set to tap 1, changeover switches ThD_U and Th1_U are turned on. As a result, the tap t1 of the secondary winding 212 is connected to the connection line 3u, and the tap t4 is connected to the neutral point N. In this case, the number of turns between the taps t1 and t4 is equal to the number of turns of the secondary winding 212, and the phase voltage of the OU phase is maximized.

For the taps 2 to 6, the changeover switch that connects the two taps to the connection line 3u and the neutral point N is determined according to the combination of taps that reduces the number of turns between taps to five levels. For example, when the tap position is set to tap 6, change-over switches ThD_U and Th3_U are turned on. As a result, the tap t3 of the secondary winding 212 is connected to the connection line 3u, and the tap t4 is connected to the neutral point N. In this case, the number of turns between the taps t3 and t4 is the minimum except zero, and the magnitude of the phase voltage of the OU phase is the minimum except zero.

When the tap position is set to tap 7, change-over switches ThD_U and Th4_U are turned on. As a result, the tap t4 of the secondary winding 212 is connected to the connection line 3u, and the same tap t4 is connected to the neutral point N. In this case, the number of turns between the taps t4 and t4 is 0, and the phase voltage of the OU phase is 0. This is the so-called straight tap.

For the taps 8 to 12, the changeover switch that connects the two taps to the connection line 3u and the neutral point N is determined according to the combination of taps that increases the number of turns between the taps to five levels. For example, when the tap position is set to tap 8, change-over switches ThC_U and Th4_U are turned on. Thereby, the tap t4 of the secondary winding 212 is connected to the connection line 3u, and the tap t3 is connected to the neutral point N. In this case, the number of turns between the taps t3 and t4 is the minimum except zero, and the magnitude of the phase voltage of the OU phase is the minimum except zero. However, compared to tap 6, the phase of the phase voltage of the OU phase is reversed.

When the tap position is set to tap 13, change-over switches ThA_U and Th4_U are turned on. Thereby, the tap t4 of the secondary winding 212 is connected to the connection line 3u, and the tap t1 is connected to the neutral point N. In this case, the number of turns between the taps t1 and t4 is equal to the number of turns of the secondary winding 212, and the phase voltage of the OU phase is maximized. However, compared to tap 1, the phase of the phase voltage of the OU phase is reversed.

As described above, the number of turns between the taps for the two taps connected to the connecting line 3u and the neutral point N by tap switching depends on the tap position, in other words, depending on the tap position, the regulating transformer A turns ratio of 2 is determined. The turn ratio referred to here is the ratio of the number of turns of the primary winding 211 to the number of turns between the taps of the two taps connected to the connection line 3u and the neutral point N by tap switching. Therefore, as shown in FIG. 2, the tap positions from tap 1 to tap 13 are associated with the turns ratio from NT_U1 to NT_U13. However, when the tap position is the tap 7, the turns ratio cannot be calculated according to the above definition, so the tap position and the turns ratio are not associated with each other. NT_U is a generic term for NT_U1 to NT_U13.

In this embodiment, a table in which the tap positions shown in FIG. By referring to this table each time the tap position is raised or lowered and reading out the information indicating the switch to be turned on and the turns ratio, the tap switching process can be easily performed.

Next, voltages added to or subtracted from the U-phase, V-phase, and W-phase AC voltages from the power supply side will be described. FIG. 3 is an explanatory diagram showing the relationship between the voltages induced in the secondary windings 212, 222, 232 of the regulating transformer 2 and the voltages applied to the primary windings 111, 121, 131 of the series transformer 1. . The secondary winding 212 of the regulating transformer 2 is connected to the connection line 3u by turning on any one of the changeover switches Th1_U, Th2_U, Th3_U, and Th4_U, and the changeover switches ThA_U, ThB_U, ThC_U, Any other tap is connected to the neutral point N by turning on any of ThD_U. The same can be said for the secondary windings 222 and 232 of the regulating transformer 2 by replacing U with V and W.

As described with reference to FIG. 2, when the tap position is any one of the taps 1 to 6 and when the tap position is any of the taps 8 to 13, the phase voltage of the OU phase is phases are inverted to each other. Here, a case where the tap position is between tap 1 and tap 6 will be described. In the regulating transformer 2, the primary windings 211, 221, 231 are delta-connected, and the secondary windings 212, 222, 232 are Y-connected via the tap changer 3. Therefore, the connection lines 3u, 3v, 3w , the phases of OU, OV, and OW lead 30 degrees with respect to the phases of u, v, and w in distribution lines 1u, 1v, and 1w as indicated by dashed lines.

On the other hand, to the primary winding 121 of the series transformer 1, V_UV, which is the phase-to-phase voltage between the OU phase and the OV phase, is applied from the terminal v2 to the terminal v1. Similarly, V_VW, which is the interphase voltage between the OV phase and the OW phase, is applied to the primary winding 131 in the direction from the terminal w2 to w1, and the primary winding 111 is applied with the voltage between the OW phase and the OU phase. A voltage, V_WU, is applied in the direction from terminal u2 to u1.

Returning now to FIG. 1, attention is directed to primary winding 121 and secondary winding 122 of series transformer 1, for example. As described above, a rightward voltage V_UV is applied between the terminals v1 and v2 of the primary winding 121 from the terminals v2 to v1. In this case, the voltage induced in the secondary winding 122 corresponding to V_UV is also a rightward voltage on the paper surface. Therefore, a voltage obtained by adding the voltage V_UV to the V-phase AC voltage from the power supply side is supplied to the load side.

On the other hand, the voltage V_UV is a voltage opposite in phase to the v-phase voltage indicated by the dashed line in FIG. That is, since the voltage V_UV having the opposite phase to the v-phase AC voltage is added to the V-phase AC voltage, the voltage having the same phase as the v-phase AC voltage is subtracted. In other words, the V-phase AC voltage from the power supply side is stepped down and the v-phase AC voltage is supplied to the load side. As the tap number of the tap position is increased from 1 to 6, the absolute value of the stepped-down voltage gradually decreases, and the stepped-down voltage at tap 7 (blank) becomes 0. After that, as the tap number of the tap position is further increased, the V-phase AC voltage from the power supply side is stepped up in sequence and supplied to the load side.

As described above, by switching the tap positions from tap 1 to tap 13, the U-phase, V-phase, and W-phase AC voltages from the power supply side are adjusted stepwise from stepped-down voltages to stepped-up voltages. , v-phase, and w-phase AC voltages. The control unit 31 detects the u-phase, v-phase, and w-phase line voltages using the measuring transformers PT1 and PT2, and when the detected voltages deviate from the dead band, the tap position is raised or lowered to detect u Phase, v-phase, and w-phase line voltages are adjusted so that they approach the reference voltage. In this embodiment, the tap positions of the secondary windings 212, 222, and 232 are adjusted to be the same. Voltage imbalance can also be improved.

Next, details of the drive unit 32 will be described. 4 and 5 are circuit diagrams showing a first configuration example of each switch for switching the taps of the secondary winding 212 and the driving section 32 in the tap changer 3 according to the first embodiment. FIG. 4 shows the configuration of changeover switches Th1_U, Th2_U, Th3_U, and Th4_U, and a circuit for driving these changeover switches. FIG. 5 shows the configuration of change-over switches ThA_U, ThB_U, ThC_U, and ThD_U, and circuits for driving these change-over switches. The configuration of each switch for switching each tap of the other secondary windings 212 and 232 and the driving section 32 is the same. The configuration of the correction switches ThS_UV and ThS_VW is the same as that of the other change-over switches, but the description of the circuit that drives these correction switches is omitted.

In the following, the names of signals are indicated by enclosing them in oblong pentagons. First, with regard to FIG. 4, the drive unit 32 selectively connects a first power supply 321a, which is an insulated DCDC converter (same below), any one of the switches Th1_u, Th2_U, Th3_U, and Th4_U, and the first power supply 321a. and a first connection circuit 331a for connecting. The first power supply 321a is for supplying an ON signal to the selector switches Th1_u, Th2_U, Th3_U, and Th4_U through the first connection circuit 331a.

Each of the selector switches Th1_U, Th2_U, Th3_U, and Th4_U has one main electrode (corresponding to one end) connected to the taps t1, t2, t3, and t4 of the secondary winding 212, and the other main electrode (corresponding to the other end). ) are connected to each other. The other main electrodes of the triacs Th1t_U, Th2t_U, Th3t_U, Th4t_U are connected to the connection line 3u and to the other end of the first power supply 321a.

The first connection circuit 331a includes transistors Q11, Q12, Q13, Q14 which are FETs (Field Effect Transistors) connecting the gates (corresponding to control terminals) of the triacs Th1t_U, Th2t_U, Th3t_U, Th4t_U and one end of the first power supply 321a. (both of which correspond to the first switching element). The first connection circuit 331a also has photocouplers PC11, PC12, PC13, and PC14 (each of which corresponds to a first isolation circuit) whose outputs are connected to the gates of the transistors Q11, Q12, Q13, and Q14, respectively. Th1ag_U, Th2ag_U, Th3ag_U, and Th4ag_U are input as exclusive first signals from the control unit 31 to the inputs of the photocouplers PC11, PC12, PC13, and PC14, respectively. Here, exclusive means that two or more of Th1ag_U, Th2ag_U, Th3ag_U, and Th4ag_U do not become significant at the same time (the same applies hereinafter).

5, the drive unit 32 includes a first power supply 321b and a first connection circuit 331b for selectively connecting any one of the switches ThA_u, ThB_U, ThC_U, ThD_U and the first power supply 321b. have. The first power supply 321b is for supplying ON signals to the change-over switches ThA_u, ThB_U, ThC_U, and ThD_U via the first connection circuit 331b.

Change-over switches ThA_U, ThB_U, ThC_U, and ThD_U are triac ThAt_U, ThBt_U having one main electrode connected to taps t1, t2, t3, and t4 of secondary winding 212 and the other main electrodes connected to each other. , ThCt_U, ThDt_U. The other main electrodes of the triacs ThAt_U, ThBt_U, ThCt_U, ThDt_U are connected to the neutral point N and to the other end of the first power supply 321b.

The configuration of the first connection circuit 331b is the same as that of the first connection circuit 331a, but the connection destination is different from that of the first connection circuit 331a. The transistors Q11, Q12, Q13, Q14 connect the gates of the triacs ThAt_U, ThBt_U, ThCt_U, ThDt_U and one end of the first power supply 321b. ThAag_U, ThBag_U, ThCag_U, and ThDag_U are input as exclusive first signals from the control unit 31 to the inputs of the photocouplers PC11, PC12, PC13, and PC14, respectively.

In the above configuration, when switching the tap position shown in FIG. 2 to tap 1, for example, the control unit 31 turns on the triacs Th1t_U and ThDt_U for the OU phase in the connection line 3u. Specifically, the control unit 31 inputs Th1ag_U as the first signal to the photocoupler PC11 of the first connection circuit 331a. The control unit 31 further inputs ThDag_U as a first signal to the photocoupler PC14 of the first connection circuit 331b. As a result, the triacs Th1t_U and ThDt_U are supplied with a trigger voltage to their gates to conduct bidirectionally. The OV phase and OW phase when switching to the tap 1 are the same as the OU phase. The same applies when switching to another tap position.

In FIGS. 4 and 5, a case where each of the change-over switches ThX_U (X=1, 2, 3, 4, A, B, C, D) includes a triac ThXt_U has been described, but the present invention is limited to this. isn't it. For example, the change-over switch ThX_U may be configured using a switch such as an interrupter or an electromagnetic contactor that includes a semiconductor element.

As described above, according to the first embodiment, eight changeover switches ThX_U (X=1, 2, 3, 4 , A, B, C, D) have one end connected to one of the taps t1, t2, t3, t4. Some of the change-over switches Th1_U, Th2_U, Th3_U, and Th4_U are connected to each other at the other ends so as to be the output of the tap changer 3 to the connection line 3u. An ON signal is alternatively supplied via . The other switches ThA_U, ThB_U, ThC_U, and ThD_U are connected to each other at the other ends so as to be the output of the tap changer 3 to the neutral point N. An ON signal is alternatively provided. Thus, when one of the changeover switches Th1_U, Th2_U, Th3_U, and Th4_U and one of the changeover switches ThA_U, ThB_U, ThC_U, and ThD_U are turned on, one tap is connected to the connection line 3u. , a tap that is the same as or different from the one tap is connected to the neutral point N. Also, all the changeover switches related to the secondary winding 212 are supplied with ON signals from either of the two first power sources 321a and 321b. Therefore, it is possible to reduce the number of power sources for turning on the eight selector switches ThX_U to two.

Further, according to the first embodiment, each of the transistors Q11, Q12, Q13, Q14 included in the first connection circuit 331a is turned on according to the first signal input via the photocouplers PC11, PC12, PC13, PC14. Then, one end of the first power supply 321a is connected to the control terminals of the switches Th1_U, Th2_U, Th3_U, and Th4_U. The other end of the first power supply 321a is connected to the other ends of the switches Th1_U, Th2_U, Th3_U, and Th4_U. Thereby, the changeover switches Th1_U, Th2_U, Th3_U, and Th4_U can be turned on by the first signal insulated from the first power supply 321a.

Similarly, when each of the transistors Q11, Q12, Q13, Q14 included in the first connection circuit 331b is turned on according to the first signal input via the photocouplers PC11, PC12, PC13, PC14, the first One end of the power supply 321b and the control terminals of the changeover switches ThA_U, ThB_U, ThC_U, and ThD_U are connected. The other end of the first power supply 321b is connected to the other ends of the switches ThA_U, ThB_U, ThC_U, and ThD_U. Thereby, the change-over switches ThA_U, ThB_U, ThC_U, and ThD_U can be turned on by the first signal insulated from the first power supply 321b.

Furthermore, according to the first embodiment, the triacs Th1t_U, Th2t_U, Th3t_U, and Th4t_U included in the change-over switches Th1_U, Th2_U, Th3_U, and Th4_U are the triggers supplied from the first power supply 321a via the first connection circuit 331a. Since the signals are bidirectionally conductive, the configuration of the switches Th1_U, Th2_U, Th3_U, Th4_U and the drive unit 32 can be simplified. Similarly, triacs ThAt_U, ThBt_U, ThCt_U, and ThDt_U included in change-over switches ThA_U, ThB_U, ThC_U, and ThD_U, respectively, are made bidirectionally conductive by a trigger signal supplied from the first power supply 321b via the first connection circuit 331b. Therefore, the configurations of the change-over switches ThA_U, ThB_U, ThC_U, ThD_U and the driving section 32 can be simplified.

(Modification 1)
In the first embodiment, the first power sources 321a and 321b are separate blocks, but they can be configured as one power source. FIG. 6 is a circuit diagram showing a configuration example of the power supply 320 used in the driving section 32 of the tap changer 3 according to Modification 1. As shown in FIG.

The power supply 320 includes an isolation transformer T1, a transistor Qd1 connected in series to one end of the primary winding of the isolation transformer T1, and a diode D1 and a capacitor C1 connected in parallel to one secondary winding of the isolation transformer T1. and a series circuit of diode D2 and capacitor C2 connected in parallel to another secondary winding. The other end of the primary winding is connected to, for example, a 24V common power supply. Diodes D1 and D2 are, for example, Schottky barrier diodes with a small forward voltage.

Resistors R1 and R2 are connected in parallel across capacitors C1 and C2, respectively. A connection point between one end of the capacitor C1 and the cathode of the diode D1 is one end of the first power supply 321a, and the other end of the capacitor C1 is the other end of the first power supply 321a. Similarly, the connection point between one end of the capacitor C2 and the cathode of the diode D2 is one end of the first power supply 321b, and the other end of the capacitor C2 is the other end of the first power supply 321b.

As described above, according to Modification 1, the two first power sources 321a and 321b for the drive unit 32 can be configured with one power source 320, and the apparent number of power sources can be further reduced. can be done.

(Embodiment 2)
In the first embodiment, for example, the controller 31 exclusively generates Th1ag_U, Th2ag_U, Th3ag_U, and Th4ag_U, which are the first signals input to the photocouplers PC11, PC12, PC13, and PC14, respectively. On the other hand, in the second embodiment, the interlock circuit generates Th1ag_U, Th2ag_U, Th3ag_U, and Th4ag_U as the first signals based on the ON/OFF signals generated by the control unit 31 for the switches Th1_U, Th2_U, Th3_U, and Th4_U, respectively. is output exclusively.

FIG. 7 is a circuit diagram showing a configuration example of an interlock circuit used in the driving section 32 of the tap changer 3 according to the second embodiment. The interlock circuit 323 a is inserted between the control section 31 and the first connection circuit 331 a included in the driving section 32 . The other interlock circuit inserted between the control unit 31 and the first connection circuit 331b has the same configuration as the interlock circuit 323a, so illustration and description thereof are omitted. The configuration of the voltage regulator 100 according to Embodiment 2 is the same as that shown in FIGS. 1 and 4 and 5 of Embodiment 1 except that an interlock circuit is added, so illustration thereof is omitted. .

The interlock circuit 323a includes four unit circuits that exclusively output Th1ag_U, Th2ag_U, Th3ag_U, and Th4ag_U as first signals. For example, a unit circuit that outputs Th1ag_U includes a 2-input OR gate OR1a, a 3-input OR gate OR1b, a 2-input AND gate AND1, and a flip-flop FF1. Other unit circuits will be described in the same manner by replacing 1 in the symbols with 2, 3, and 4. A unit circuit that outputs Th1ag_U will be mainly described below.

Th1n_U and Th1f_U, which are ON/OFF signals generated by the control unit 31, are input to one input of each of the AND gate AND1 and the OR gate OR1a. This signal is generated when The output of the OR gate OR1b is input to the other input of the OR gate OR1a. The output of the OR gate OR1a is input to the other input of the AND gate AND1 and the R terminal of the flip-flop FF1. The output of the AND gate AND1 is input to the S terminal of the flip-flop FF1. Th2x_U, Th3x_U, and Th4x_U, which are the outputs of the other three unit circuits, are input to the three inputs of the OR gate OR1b. Th1ag_U and Th1x_U are output from the Q terminal of the flip-flop FF1.

When the control unit 31 turns off the switch Th1_U, Th1f_U is input to the unit circuit, the OR gate OR1a opens, the AND gate AND1 closes, and the flip-flop FF1 is reset. As a result, Th1ag_U and Th1x_U are not output. When any one of Th2x_U, Th3x_U, and Th4x_U is output from the other three unit circuits, Th1ag_U and Th1x_U are not output because the OR gate OR1a opens regardless of whether Th1n_U and Th1f_U are input.

When the control unit 31 turns on the switch Th1_U, Th1n_U is input to the unit circuit. In this state, the AND gate AND1 is opened and the flip-flop FF1 is set only when Th1f_U is not input and neither Th2x_U, Th3x_U, or Th4x_U is input. As a result, Th1ag_U and Th1x_U are output.

In the case of a unit circuit that outputs Th2ag_U as the first signal, Th2ag_U and Th2x_U are output based on Th2n_U and Th2f_U input from the control unit 31 and Th1x_U, Th3x_U, and Th4x_U input from other unit circuits. be. In the case of a unit circuit that outputs Th3ag_U as the first signal, Th3ag_U and Th3x_U are output based on Th3n_U and Th3f_U input from the control unit 31 and Th1x_U, Th2x_U, and Th4x_U input from other unit circuits. be. In the case of a unit circuit that outputs Th4ag_U as the first signal, Th4ag_U and Th4x_U are output based on Th4n_U and Th4f_U input from the control unit 31 and Th1x_U, Th2x_U, and Th3x_U input from other unit circuits. be.

The configuration of the interlock circuit is not limited to that shown in FIG. 7, and can be realized by a configuration in which logic circuits such as various gates and flip-flops are combined.

As described above, according to the second embodiment, while any one of Th2ag_U, Th3ag_U, and Th4ag_U is being output as the first signal from the interlock circuit 323a to the first connection circuit 331a, the output of Th1ag_U is It is forbidden. Therefore, it is possible to reliably prevent two or more of the four switches connected to the first connection circuit 331a from being turned on at the same time.

(Embodiment 3)
While the first embodiment includes a triac in each changeover switch, the third embodiment includes a thyristor connected in anti-parallel to each changeover switch. Since the overall configuration of the voltage regulator 100 according to the third embodiment is the same as that shown in FIG. 1 of the first embodiment, the illustration is omitted.

Details of the drive unit 32 different from the first embodiment will be described. 8 and 9 are circuit diagrams showing a second configuration example of each switch for switching the taps of the secondary winding 212 and the driving section 32 in the tap changer 3 according to the third embodiment. FIG. 8 shows the configuration of changeover switches Th1_U, Th2_U, Th3_U, and Th4_U, and a circuit for driving these changeover switches. FIG. 9 shows the configuration of change-over switches ThA_U, ThB_U, ThC_U, and ThD_U and a circuit for driving these change-over switches. The configuration of each switch for switching the taps of the other secondary windings 222 and 232 and the driving section 32 is the same.

First, referring to FIG. 8, the drive unit 32 has a first power supply 321a, and a first connection circuit 331a for selectively connecting any one of the switches Th1_u, Th2_U, Th3_U, Th4_U and the first power supply 321a. . The drive unit 32 also has a second power supply 322a and a second connection circuit 332a for selectively connecting any one of the switches Th1_u, Th2_U, Th3_U, and Th4_U and the second power supply 322a.

The change-over switch Th1_U is formed by connecting in anti-parallel a first thyristor Th1a_U whose anode is connected to the tap t1 of the secondary winding 212 and a second thyristor Th1b_U whose anode is connected to the connection line 3u. The change-over switch Th2_U is formed by connecting in anti-parallel a first thyristor Th2a_U whose anode is connected to the tap t2 of the secondary winding 212 and a second thyristor Th2b_U whose anode is connected to the connection line 3u. The change-over switch Th3_U is formed by connecting in anti-parallel a first thyristor Th3a_U whose anode is connected to the tap t3 of the secondary winding 212 and a second thyristor Th3b_U whose anode is connected to the connection line 3u. The change-over switch Th4_U is formed by connecting in anti-parallel a first thyristor Th4a_U whose anode is connected to the tap t4 of the secondary winding 212 and a second thyristor Th4b_U whose anode is connected to the connection line 3u. That is, one end of each change-over switch Th1_U, Th2_U, Th3_U, and Th4_U is connected to taps t1, t2, t3, and t4, and the other ends are connected to the connection line 3u. These other ends are also connected to the other end of the first power supply 321a.

The configuration of the first connection circuit 331a is the same as that shown in FIG. 4 of the first embodiment, and the connection destination is different from that of the first embodiment. Each of the transistors Q11, Q12, Q13, Q14 connects the gates of the first thyristors Th1a_U, Th2a_U, Th3a_U, Th4a_U and one end of the first power supply 321a. The same Th1ag_U, Th2ag_U, Th3ag_U, and Th4ag_U as in the first embodiment are input to the photocouplers PC11, PC12, PC13, and PC14 as exclusive first signals.

The second connection circuit 332a has transistors Q21, Q22, Q23, Q24 that connect the gates of the second thyristors Th1b_U, Th2b_U, Th3b_U, Th4b_U and one end of the second power supply 322a. The second connection circuit 332a also has photocouplers PC21, PC22, PC23, and PC24 whose outputs are connected to the gates of transistors Q21, Q22, Q23, and Q24, respectively. Th1bg_U, Th2bg_U, Th3bg_U, and Th4bg_U are input as exclusive second signals from the control unit 31 to the inputs of the photocouplers PC21, PC22, PC23, and PC24, respectively.

The second connection circuit 332a has transistors Q31, Q32, Q33, Q34 that connect the cathodes of the second thyristors Th1b_U, Th2b_U, Th3b_U, Th4b_U and the other end of the second power supply 322a. The second connection circuit 332a also has photocouplers PC31, PC32, PC33, and PC34 whose outputs are connected to the gates of transistors Q31, Q32, Q33, and Q34, respectively. Th1bc_U, Th2bc_U, Th3bc_U, and Th4bc_U are input as exclusive third signals from the control unit 31 to the inputs of the photocouplers PC31, PC32, PC33, and PC34, respectively.

9, the drive unit 32 includes a first power supply 321b and a first connection circuit 331b for selectively connecting any one of the switches ThA_u, ThB_U, ThC_U, ThD_U and the first power supply 321b. have. The drive unit 32 also has a second power supply 322b and a second connection circuit 332b for selectively connecting any one of the change-over switches ThA_u, ThB_U, ThC_U, ThD_U and the second power supply 322b.

The change-over switch ThA_U is formed by connecting a first thyristor ThAa_U whose anode is connected to the tap t1 of the secondary winding 212 and a second thyristor ThAb_U whose anode is connected to the neutral point N in antiparallel. The selector switch ThB_U is formed by connecting a first thyristor ThBa_U whose anode is connected to the tap t2 of the secondary winding 212 and a second thyristor ThBb_U whose anode is connected to the neutral point N in antiparallel. The selector switch ThC_U is formed by connecting a first thyristor ThCa_U whose anode is connected to the tap t3 of the secondary winding 212 and a second thyristor ThCb_U whose anode is connected to the neutral point N in antiparallel. The selector switch ThD_U is formed by connecting a first thyristor ThDa_U whose anode is connected to the tap t4 of the secondary winding 212 and a second thyristor ThDb_U whose anode is connected to the neutral point N in antiparallel. That is, one end of each change-over switch ThA_U, ThB_U, ThC_U, and ThD_U is connected to taps t1, t2, t3, and t4, and the other ends are connected to the neutral point N, respectively. These other ends are also connected to the other end of the first power supply 321b.

The first connection circuit 331b has the same configuration as the first connection circuit 331a, but the connection destination is different from that of the first connection circuit 331a. Each of the transistors Q11, Q12, Q13, Q14 connects the gates of the first thyristors ThAa_U, ThBa_U, ThCa_U, ThDa_U and one end of the first power supply 321b. The cathodes of the first thyristors ThAa_U, ThBa_U, ThCa_u, ThDa_U are connected to the other end of the first power supply 321b. ThAag_U, ThBag_U, ThCag_U, and ThDag_U are input as exclusive third signals from the control unit 31 to the inputs of the photocouplers PC11, PC12, PC13, and PC14, respectively.

The second connection circuit 332b has the same configuration as the second connection circuit 332a, but the connection destination is different from that of the second connection circuit 332a. Each of the transistors Q21, Q22, Q23, Q24 connects the gates of the second thyristors ThAb_U, ThBb_U, ThCb_U, ThDb_U and one end of the second power supply 322b. ThAbg_U, ThBbg_U, ThCbg_U, and ThDbg_U are input as exclusive second signals from the control unit 31 to the inputs of the photocouplers PC21, PC22, PC23, and PC24, respectively. Each of the transistors Q31, Q32, Q33, Q34 connects the cathodes of the second thyristors ThAb_U, ThBb_U, ThCb_U, ThDb_U and the other end of the second power supply 322b. ThAbc_U, ThBbc_U, ThCbc_U, and ThDbc_U are input as exclusive third signals from the control unit 31 to the inputs of the photocouplers PC31, PC32, PC33, and PC34, respectively.

In the above-described configuration, when switching to tap 1 shown in FIG. 2, for example, the control unit 31 turns on the changeover switches Th1_U and ThD_U for the OU phase in the connection line 3u. Specifically, the control unit 31 inputs Th1ag_U as the first signal to the photocoupler PC11 of the first connection circuit 331a, and inputs Th1bg_U and Th1bg_U as the second and third signals to the photocouplers PC21 and PC31 of the second connection circuit 332a, respectively. Enter Th1bc_U. The control unit 31 further inputs ThDag_U as a first signal to the photocoupler PC14 of the first connection circuit 331b, and ThDbg_U and ThDbc_U as second and third signals to the photocouplers PC24 and PC34 of the second connection circuit 332b, respectively. Enter As a result, the change-over switches Th1_U and ThD_U are bidirectionally conductive. The OV phase and OW phase when switching to the tap 1 are the same as the OU phase. The same applies when switching to another tap position.

As described above, according to the third embodiment, the first thyristor ThXa_U and the second thyristor ThXa_U connected in anti-parallel to each selector switch ThX_U (X=1, 2, 3, 4, A, B, C, D) ThXb_U is included. The first thyristors Th1a_U, Th2a_U, Th3a_U, and Th4a_U whose cathodes are connected to each other are selectively supplied with a trigger signal from the first power source 321a via the first connection circuit 331a. The first thyristors ThAa_U, ThBa_U, ThCa_U, and ThDa_U, whose cathodes are connected to each other, are alternatively supplied with a trigger signal from the first power source 321b via the first connection circuit 331b.

The anodes of the second thyristors Th1b_U, Th2b_U, Th3b_U, and Th4b_U included in the change-over switches Th1_U, Th2_U, Th3_U, and Th4_U are connected to each other, and are triggered by an insulated second power source 322a via a second connection circuit 332a. A signal is alternatively supplied. The anodes of the second thyristors ThAb_U, ThBb_U, ThCb_U, and ThDb_U included in the selector switches ThA_U, ThB_U, ThC_U, and ThD_U are connected to each other, and are triggered by the second power source 322b of the insulating type via the second connection circuit 332b. A signal is alternatively supplied. Therefore, the first thyristor and the second thyristor included in one of the change-over switches Th1_U, Th2_U, Th3_U, Th4_U and the first thyristor and the second thyristor included in one of the change-over switches ThA_U, ThB_U, ThC_U, ThD_U When the two thyristors are turned on, one of the taps t1, t2, t3, and t4 is connected to the connection line 3U, and the same or different tap as the one tap is connected to the neutral point N. . All the first thyristors and second thyristors associated with the secondary winding 212 are supplied with trigger signals from either the first power sources 321a, 321b or the second power sources 322a, 322b.

Further, according to the third embodiment, the transistors Q21, Q22, Q23, and Q24 included in the second connection circuit 332a are turned on according to the second signals input via the photocouplers PC21, PC22, PC23, and PC24, respectively. When the transistors Q31, Q32, Q33, and Q34 are turned on in response to the third signal input via the photocouplers PC31, PC32, PC33, and PC34, one end and the other end of the second power supply 322a and the second The gates and cathodes of the thyristors Th1b_U, Th2b_U, Th3b_U, Th4b_U are connected. Accordingly, the second thyristors Th1b_U, Th2b_U, Th3b_U, and Th4b_U included in the switches Th1_U, Th2_U, Th3_U, and Th4_U can be turned on by the second signal and the third signal isolated from the second power supply 322a. Further, while the second thyristors Th1b_U, Th2b_U, Th3b_U, and Th4b_U are off, the taps to which the anodes of these thyristors are connected are separated from the second power supply 322a, thereby preventing a short circuit between the taps. can be done.

Similarly, the transistors Q21, Q22, Q23, Q24 of the second connection circuit 332b are turned on in response to the second signals input via the photocouplers PC21, PC22, PC23, PC24, and the transistors Q31, Q32, When Q33 and Q34 are turned on according to the third signal input via photocouplers PC31, PC32, PC33 and PC34, one end and the other end of the second power supply 322b and the second thyristors ThAb_U, ThBb_U and ThCb_U , ThDb_U are connected. Accordingly, the second thyristors ThAb_U, ThBb_U, ThCb_U, and ThDb_U included in the switches ThA_U, ThB_U, ThC_U, and ThD_U can be turned on by the second and third signals isolated from the second power supply 322b. Also, while the second thyristors ThAb_U, ThBb_U, ThCb_U, and ThDb_U are off, the taps to which the anodes of these thyristors are connected are separated from the second power supply 322b, thereby preventing a short circuit between the taps. can be done.

When using the same interlock circuit as in the second embodiment, two interlock circuits may be used for the first connection circuits 331a and 331b as in the second embodiment. In this case, the first signals exclusively output from these two interlock circuits can be applied to the second connection circuits 332a and 332b as the second and third signals.

(Modification 2)
In the third embodiment, it is assumed that the control unit 31 individually outputs the first signal and the second and third signals to the first connection circuit and the second connection circuit corresponding to one changeover switch. However, these signals may be output simultaneously from the same circuit. FIG. 10 is a circuit diagram showing a configuration example of a driver circuit used in the driving section 32 of the tap changer 3 according to Modification 2. As shown in FIG.

The driver circuit 324 shown in FIG. 10 outputs Th1ag_U, Th1bg_U, and Th1bc_U, which are the first signal and the second and third signals input to the first connection circuit 331a and the second connection circuit 332a, respectively, based on Th1x_U. It is. The same applies to the driver circuit that outputs ThAag_U, ThAbg_U, and ThAbc_U, which are the first signal and the second and third signals input to the first connection circuit 331b and the second connection circuit 332b, based on ThAx_U. Generally, a driver circuit for outputting ThXag_U and ThXbg_U, ThXbc_U (X=1, 2, 3, 4, A, B, C, D) based on ThXx_U has the same configuration as in FIG.

The driver circuit 324 has resistors R3, R3, R3, R3, one end of which is connected to the power supply Vcc, and four buffer ICs 325 of which the other ends of these resistors are connected to input terminals and pulled up. . When Th1x_U is input to the enable terminal of the buffer IC 325, the outputs of the four circuits of the buffer IC 325 become active, and Th1ag_U, Th1bg_U, and Th1bc_U are simultaneously output.

Th1x_U may be input, for example, from the interlock circuit 323a shown in FIG. When the first, second, and third signals Th1ag_U, Th1bg_U, and Th1bc_U are active low signals, one end of the resistors R3, R3, R3, and R3 is connected to the signal ground of the driver circuit 324. The other ends of these resistors may be connected to four input terminals of the buffer IC 325 and pulled down.

As described above, according to Modification 2, the first thyristor and the second thyristor included in each switch can be reliably driven simultaneously.

(Modification 3)
In modification 2, Th1ag_U and Th1bg_U and Th1bc_U are input in parallel. In Modification 3, Th1ag_U and Th1bg_U and Th1bc_U are equivalently input in series to photocouplers PC11 and photocouplers PC21 and PC31, respectively.

FIG. 11 is a circuit diagram showing a configuration example of a driver circuit used in the driving section 32 of the tap changer 3 according to Modification 3. As shown in FIG. In general, a driver circuit that equivalently outputs ThXag_U and ThXbg_U, ThXbc_U (X=1, 2, 3, 4, A, B, C, D) based on ThXx_U has the same configuration as in FIG. be.

The driver circuit 326 has an inverter 327 and an electric path for connecting the input sides of the photocouplers PC11, PC31, and PC21 in series between the output of the inverter 327 and the power supply Vcc. Specifically, the power supply Vcc is connected by an electric path to the output of the inverter 327 via the photodiodes of the photocouplers PC11, PC31, and PC21 in series.

When Th1x_U is input to the inverter 327 included in the driver circuit 326, a common current flows through the photodiodes of the photocouplers PC11, PC31, and PC21. In this case, Th1ag_U, Th1bg_U, and Th1bc_U are equivalently input simultaneously to the photocouplers PC11, PC21, and PC31, respectively.

As described above, according to Modification 3, the first thyristor and the second thyristor included in each switch can be reliably driven simultaneously.

According to the present application, not only can the tap changer 3 having such a characteristic configuration be realized, but also the on-load tap-changing transformer 200 including the tap changer 3, the voltage regulator 100, and the thyristor type A voltage regulator (TVR = Thyristor type Step Voltage Regulator) can also be realized.

The embodiments disclosed this time should be considered as examples in all respects and not restrictive. The scope of the present invention is indicated by the scope of the claims rather than the meaning described above, and is intended to include all modifications within the scope and meaning equivalent to the scope of the claims. Also, the technical features described in each embodiment can be combined with each other.

1u, 1v, 1w distribution line 100 voltage regulator 1 series transformer 111, 121, 131 primary winding 112, 122, 132 secondary winding u1, u2, v1, v2, w1, w2 terminals, 200 on-load tap-changing transformer, 2 regulating transformer, 211, 221, 231 primary winding, 212, 222, 232 secondary winding, t1, t2, t3, t4 taps, 3 tap changer, 31 control unit, 32 drive unit 320 power supply 321a, 321b first power supply 322a, 322b second power supply 324, 326 driver circuit 325 buffer IC 327 inverter 331a, 331b first connection circuit 332a, 332b second connection circuit PC11, PC12, PC13, PC14, PC21, PC22, PC23, PC24, PC31, PC32, PC33, PC34 Photocoupler Q11, Q12, Q13, Q14, Q21, Q22, Q23, Q24, Q31, Q32, Q33, Q34 Transistor , Th1_U, Th2_U, Th3_U, Th4_U, ThA_U, ThB_U, ThC_U, ThD_U Switch, Th1t_U, Th2t_U, Th3t_U, Th4t_U, ThAt_U, ThBt_U, ThCt_U, ThDt_U Triac, Th1a_U , Th2a_U, Th3a_U, Th4a_U, ThAa_U, ThBa_U, ThCa_U, ThDa_U First thyristor Th1b_U, Th2b_U, Th3b_U, Th4b_U, ThAb_U, ThBb_U, ThCb_U, ThDb_U Second thyristor 3u, 3v, 3w Connection line ThS_UV, ThS_VW Breaking switch R_UV, R_VW Current limiting resistor MC_UV, MC_VW magnetic contactor, PT1, PT2, PT3, PT4, PT5 measuring transformer

Claims (6)

An on-load tap changer comprising a plurality of changeover switches for switching a plurality of taps of a winding of a tapped transformer, and driving the plurality of changeover switches to ON,
one end of each of the plurality of selector switches is connected to one of the plurality of taps;
Some changeover switches and other changeover switches excluding the part are connected to each other at the other ends,
two insulation-type first power sources for separately supplying an ON signal to each of the partial changeover switch and the other changeover switch;
An on-load tap changer, comprising: a first connection circuit for selectively connecting each first power supply and a switch to which an ON signal is supplied from each; Each first connection circuit is turned on in response to a first signal input via a first isolation circuit between one end of the corresponding first power supply and the control terminal of the corresponding change-over switch. 1 switching element,
2. The on-load tap changer according to claim 1, wherein the other end of each first power supply is connected to the other end of a change-over switch to which an ON signal is supplied from each first power supply. 3. The on-load tap changer according to claim 2, wherein an interlock circuit for exclusively outputting the first signal input to each first connection circuit is provided for each first connection circuit. each changeover switch includes a triac conducting in both directions,
The on-load tap changer according to any one of claims 1 to 3, wherein the ON signal is a trigger signal supplied to a triac included in each changeover switch. Each switch includes a first thyristor whose anode is connected to one of the taps and a second thyristor connected in anti-parallel with the first thyristor,
The ON signal is a trigger signal supplied to a first thyristor included in each switch,
two isolated second power supplies for separately supplying trigger signals to the second thyristors included in each of the partial changeover switch and the other changeover switch;
The on-load tap according to any one of claims 1 to 3, further comprising: a second connection circuit for selectively connecting each second power supply and the second thyristor to which a trigger signal is supplied from each. Switcher. Each second connection circuit is
Second switching that is turned on according to a second signal input via a second isolation circuit between one end of the corresponding second power supply and the gate of the second thyristor included in the corresponding changeover switch having an element,
A third switching circuit which is turned on according to a third signal input via a third insulating circuit between the other end of the corresponding second power supply and the cathode of the second thyristor included in the corresponding switching switch. 6. The on-load tap changer of claim 5, comprising a switching element.

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