JP2012156038A - Drive control circuit for automatic distribution line circuit breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive control circuit for an automatic distribution line circuit breaker, capable of switch-on operation of a main switch without burdening an excess load on a control power transformer for outputting a power voltage by stepping down a distribution line voltage.SOLUTION: The drive control circuit includes: an auxiliary switch 12, provided to mechanically cooperate with main switches Su-Sw, for retaining an ON state when the main switches are in an open path state and for retaining an OFF state when the main switches are in an ON state; an excitation changeover switch 11 which is connected in series with the auxiliary switch 12 and becomes an ON state only for a certain period of time when the main switches are switched ON; and a current-limiting element 13 connected in parallel to both ends of the auxiliary switch 12. Between output terminals of a rectifier 7 for rectifying the output of a control power transformer 6, a switch-on coil 3 for the main switches is connected through a parallel circuit of the auxiliary switch 12 and the current-limiting element 13 and through the excitation changeover switch 11.

Description

  The present invention relates to a drive control circuit for an automatic switch connected to a distribution line.

  As disclosed in Patent Document 1, an automatic switch is used as a switch that is inserted into a dividing point or a branch point of a distribution line. This type of switch performs a main switch inserted in series in the distribution line, a main switch closing operation, a closing holding operation (an operation for maintaining the closing state), and an opening operation using an electromagnet as a driving source for operation. And a manual operation mechanism that allows the main switch to be turned on and open by manual operation, and the electromagnet is energized by a drive control circuit provided in the switch slave station attached to the switch. By controlling this, the operation of turning on and holding the main switch is performed. The electromagnet includes a return spring, and when the energization of the exciting coil of the electromagnet is cut off, the opening operation of the main switch is performed by the action of the return spring.

  In an automatic switch for power distribution, a large electromagnetic force is required when the main switch is turned on, but when the main switch is turned on after the main switch is turned on, the electromagnetic force is Even if it weakens, it does not cause trouble. Therefore, in this type of switch, as shown in Patent Document 1, as an exciting coil of an electromagnet, a closing coil and a holding coil having a larger impedance than that of the closing coil are provided, and the exciting power source is changed to the closing coil. The main switch is turned on by supplying a sufficiently large input current, and then the main switch is held in the on state by supplying a limited current to the holding coil.

  FIG. 5 shows an automatic switch for power distribution and a conventional drive control circuit for controlling the automatic switch. In the figure, 1 is an automatic switch, and 2 is a switch slave station constituting the main part of the drive control circuit. The automatic switch 1 includes main switches Su, Sv and Sw inserted in series in U, V and W three-phase distribution lines, respectively, and a closing coil (CC) which is excited when these main switches are automatically operated. 3 and an electromagnet having a holding coil (HC) 4. In the illustrated example, a closing coil 3 and a holding coil 4 are connected in series, an electromagnet having these coils, a mechanism for transmitting the displacement of the movable iron core of the electromagnet to the movable contact of the main switch, and a main switch. An electromagnetic operating mechanism of the automatic switch is configured by a return spring that biases the movable iron core to the opening side.

  In addition to the electromagnetic operation mechanism, the automatic switch 1 is also provided with a manual operation mechanism for forcibly opening the main switches Su to Sw and turning them on by manually operating the operation handle via the operation cord. Thus, the opening and closing operations of the main switches Su to Sw can be performed also by manual operation.

  The illustrated switch slave station 2 includes a rectifier 7 in which the output of the control power transformer 6 that steps down the voltage of the distribution line is input through the switch 5, and a resistor 8 and a capacitor 9 that are connected between the DC output terminals of the rectifier 7. And a timer relay 10 that starts a timed operation when the output voltage of the control power transformer 6 is applied to the rectifier 7 through the switch 5, and the output voltage of the rectifier 7 is the input coil 3. And the holding coil 4 are applied to both ends of a series circuit.

  The timer relay 10 includes a normally open contact MCa, and an excitation changeover switch 11 is configured by the contact MCa. The contact MCa constituting the excitation changeover switch 11 is connected in parallel to both ends of the holding coil HC, and the holding coil HC is short-circuited when the contact MCa is in an on state. When the output voltage of the control transformer 6 is input to the rectifier 7 through the switch 5 and the rectifier generates the output voltage, the timer relay 10 starts a timed operation for measuring a predetermined time T, and sets the contact MCa for a predetermined time. Turn on for T.

  The control power transformer 6 may be provided in the automatic switch 1 or may be provided outside the automatic switch. In the illustrated example, an excitation power source is constituted by a control power transformer 6, a switch 5, a rectifier 7, a smoothing circuit comprising a resistor 8 and a capacitor 9, and an automatic switch is constituted by this excitation power source and the timer relay 10. A drive control circuit for controlling energization to the making coil 3 and the holding coil 4 is configured to perform the making operation 1 and the making and holding operation and the opening operation. The switch 5 is turned off when the power of the switch slave station 2 is turned off as necessary, but is normally kept in the on state.

  In the operation mode of the automatic switch 1, the energization to the closing coil 3 and the holding coil 4 is controlled by the drive control circuit when a condition for allowing the closing operation and the opening operation to be performed automatically is satisfied. Thus, there are an automatic mode in which the main switches Su to Sw are automatically turned on and opened, and a manual mode in which the main switches Su to Sw are opened and turned on manually.

  In automatic mode, when the substation breaker is turned on and voltage is applied to the distribution line upstream of the installation point, the main switch Su or Sw is automatically turned on and the substation breaker is opened. Thus, the main switch is automatically opened when the voltage of the distribution line disappears.

  By the way, in the power distribution system, when an accident that requires restoration work occurs in a specific section, the circuit breaker of the power supply substation of the system is opened, and power is supplied from the mobile power generator to the healthy section downstream from the accident section. In such a state, the automatic switch (section switch) between the accident section and the healthy section is manually opened to disconnect the accident section from the system, and without causing a power failure in the section downstream from the accident section, Perform recovery work. After the restoration work for the accident section is completed, turn on the circuit breaker of the power substation and turn on the power supply side switch in the section where the work is completed. At this time, the switch on the downstream side of the section where the restoration work has been completed (the work completion section) is in a state where it is opened manually. In this state, adjust the power generation output of the mobile power generator that supplies power to the section downstream from the section where the construction is completed, and the voltage supplied from the power substation in the section where the construction is completed , After synchronizing with the output of the mobile power generator, manually turn on the switch on the downstream side of the construction end section that is open in the manual mode, and then turn on the switch by electromagnetic operation Switch the operation mode of the switch to the automatic mode (the state where the electromagnetic is turned on). Through these operations, the power supply of the system is switched from the mobile power generator to the transformer of the power supply substation without any power failure.

  As mentioned above, when the accident recovery work is completed, in order to perform the operation of switching the power supply of the system without interruption, the switch that has been opened is manually turned on and then manually turned on and off. It is necessary to change the operation mode of the switch to the automatic mode by shifting the switch to a state in which the electromagnetic switch is turned on as it is. The drive control circuit shown in FIG. 5 is configured to be able to perform such a switching operation.

  In the drive control circuit shown in FIG. 5, when the substation breaker is turned on and voltage is applied to the distribution line upstream of the installation point of the automatic switch 1 (substation side), automatic switching FIG. 6 shows a time chart showing the operation when the container is automatically charged. 6A schematically shows the output voltage of the rectifier 7, and FIG. 6B schematically shows the current flowing through the making coil and the holding coil. 6C shows the on / off operation of the contact MCa (excitation switching switch) of the timer relay 10, and FIG. 6D shows the on / off operation of the main switches Su to Sw.

  In the drive control device shown in FIG. 5, the control power transformer 6 steps down the distribution line voltage upstream of the installation point of the automatic switch 1 and supplies it to the rectifier 7. As shown in FIG. 6A, when a voltage is applied to the distribution line upstream of the installation point of the automatic switch at time t1, and a voltage is applied from the control power transformer 6 to the rectifier 7, the timer relay 10 is turned on. When the operation starts, the contact MCa constituting the excitation changeover switch 11 is turned on as shown in FIG. 6C, so that the holding coil 4 is short-circuited through the contact MCa and the output voltage of the rectifier 7 is changed to the input coil 3. Applied to both ends. Therefore, as shown in FIG. 6B, a making current Icc flows through the making coil 3. As a result, the movable iron core of the electromagnet is attracted to the inside of the exciting coil, and due to the displacement of the movable iron core, the movable contacts of the main switches Su to Sw are displaced toward the fixed contacts, and the main switch is turned on. When the turning on of the main switches Su to Sw is completed at time t2, the current Icc flowing through the making coil 3 increases, and a very large current flows because the movable iron core eventually becomes magnetically saturated.

  When a certain time T elapses after the voltage is applied to the distribution line and the time t3 is reached, the contact MCa is turned off, the short circuit of the holding coil 4 is released, and the holding coil 4 is connected in series with the closing coil 3. Therefore, the excitation current decreases in a stepped manner up to the holding current Ihc. While the voltage is applied to the distribution line and the voltage is applied from the control transformer 6 to the rectifier 7, the holding current Ihc continues to flow through the holding coil 4, and the main switches Su to Sw are held in the ON state. When the distribution line voltage upstream of the automatic switch installation point is reduced to zero at time t4, the holding current Ihc flowing through the closing coil 3 and the holding coil 4 is cut off. Su to Sw are automatically opened.

  As described above, in the drive control circuit of the automatic switch for power distribution, the excitation changeover switch 11 that keeps the ON state for a certain time T from the time t1 when the voltage is applied to the rectifier 7 from the control transformer 6 is provided. An energizing current is supplied from the exciting power source to the energizing coil 3 for a certain time T while the switch 11 is kept on. When the elapse of the certain time T, the switch 11 is opened and the retaining current restricted through the retaining coil 4 is limited. When the structure is switched to the state where the current flows, the time T for holding the excitation switch 11 in the ON state needs to be set to be somewhat long, so that the switch is turned on even after the main switches Su to Sw are turned on. It was inevitable that a large excitation current continued to flow through the coil 3. In this case, if the capacity of the control power transformer 6 is insufficient, the output voltage of the control power transformer 6 is greatly reduced when a large current flows through the input coil 3, and other components provided in the switch slave station 2. May malfunction.

  For example, the switch slave station is provided with an accident determination unit that determines that the distribution line has failed when the output voltage of the control power transformer 6 falls below the set determination voltage. If the output voltage of the control power transformer 6 is greatly reduced, there is a risk that this voltage drop is erroneously determined as a power failure. In order to prevent such an erroneous determination in the switch slave station 2, it is necessary to use a control power transformer 6 having a large capacity. However, if the capacity of the transformer 6 is increased, the transformer 6 In addition to the increase in size, there arises a problem that the cost is increased.

  Therefore, as shown in Patent Document 2, a drive control circuit for an automatic switch for distribution lines has been proposed in which the current flowing through the closing coil can be limited after the main switch has been turned on. . FIG. 7 shows the configuration of the drive control circuit disclosed in Patent Document 2, in which 1 is an automatic switch and 2 is a switch slave station. The switch slave station 2 includes a rectifier 7 that rectifies the output of the control power transformer 6, and the output voltage of the rectifier 7 is applied to both ends of the series circuit of the holding coil 4 and the closing coil 3. The output voltage of the rectifier 7 is also applied to the coil of the relay 22 through a contact 21 that is mechanically interlocked with the main switches Su to Sw. The contact 21 mechanically interlocked with the main switches Su to Sw is in an on state when the main switches Su to Sw are in an open state, and is in an off state when the main switches Su to Sw are turned on. The output voltage of the rectifier 7 is also applied to the coil of the delay operation relay 25 through the contact 21, the diode 23, and the resistor 24, and a timer capacitor 26 is connected in parallel across the coil of the relay 25. The timer capacitor 26 is charged with a constant time constant through the contact 21, the diode 23, and the resistor 24 when the rectifier 7 generates an output voltage.

  The relays 22 and 25 have normally open contacts 22a and 25a, respectively, and the output voltage of the rectifier 7 is applied to both ends of the closing coil 3 through the contacts 25a and 22a. A temperature sensitive resistance element (resistance element whose resistance value increases as temperature rises) 28 having a positive temperature coefficient is connected in parallel to both ends of the contact 22a. The delay operation relay 25 operates when a predetermined time has elapsed after the rectifier 7 generates the output voltage and the voltage across the timer capacitor 26 reaches a set value, and turns on the contact 25a. When a certain time elapses after the contact 21 is opened and the voltage across the timer capacitor 26 drops to a predetermined value, the contact 25a is turned off.

  In the drive control circuit shown in FIG. 7, when voltage is applied to the distribution line upstream of the installation point of the automatic switch 1 with the main switches Su to Sw open and the contact 21 closed. Since the output voltage of the rectifier 7 is applied to the coil of the relay 22 through the contact 21, the relay 22 is excited and the contact 22a is turned on. After a certain period of time has elapsed after the relay 22 is energized, the delay operation relay 25 operates to close the contact 25a, so that a current is supplied from the rectifier 7 to the closing coil 3 through the contacts 25a and 22a. As a result, the main switches Su to Sw are turned on. When the main switches Su to Sw are turned on, the contact 21 is opened, so that the relay 22 is demagnetized and the contact 22a is opened. Therefore, the temperature sensitive resistance element 28 is connected in series with the making coil 3, and the current flowing through the making coil 3 is limited. When the current flowing through the making coil flows through the temperature-sensitive resistance element 28, the temperature of the temperature-sensitive resistance element 28 rises, so that the resistance value increases and the current flowing through the making coil 3 decreases.

  When a predetermined time has elapsed after the main switches Su to Sw are completely turned on and the contact 21 is opened, the delay operation relay 25 is demagnetized, so that the contact 25a is opened. As a result, a limited holding current flows from the rectifier 7 through the holding coil 4 and the closing coil 3, and the main switches Su to Sw are held in the closing state.

Japanese Patent Laid-Open No. 4-101314 JP-A-1-291409

  As described above, according to the drive control circuit described in Patent Document 2 (FIG. 7), when the main switches Su to Sw are completely turned on, the temperature sensitive resistance element 28 is connected in series with the closing coil 3. Since it is inserted, the current flowing through the closing coil is limited, and the burden on the control power transformer 6 is reduced.

  However, in the drive control circuit shown in FIG. 7, the automatic switch 1 is manually turned on when the power supply of the system is switched from the mobile power generator to the transformer of the power substation after the restoration work for the accident section is completed. After that, there was a problem that it was not possible to shift to the state where the electromagnetic was input as it was. That is, in the drive control circuit shown in FIG. 7, when the main switches Su to Sw of the automatic switch on the downstream side of the section where the restoration work has been completed are manually turned on, the main switches Su to Sw are interlocked. Therefore, even when a voltage is applied from the control power transformer 6 to the rectifier 7, the relay 22 is not excited and the contact 22a cannot be closed. At this time, the contact point 25a of the relay 25 is also kept open, so that no current can flow through the closing coil 3, and the main switch cannot be shifted to the electromagnetically switched state. In order to shift the main switch to the electromagnetically switched state, it is necessary to apply the output voltage of the control power transformer 6 to the rectifier 7 after the main switches Su to Sw are once opened manually. When the restoration work is completed, the operation of switching the power supply of the system from the mobile power generation device to the transformer of the power supply substation cannot be performed without a power failure.

  The object of the present invention is to allow the main switch to be turned on automatically without imposing a heavy burden on the control power transformer so that the control power transformer can be reduced in size and cost can be reduced manually. Automatic switching for power distribution, which allows the system to be switched to an electromagnetically switched on state without opening the main switch as it is, so that uninterruptible switching of the system power supply can be performed at the time of accident recovery An object of the present invention is to provide a drive control circuit for a container.

  The present invention comprises a main switch inserted in series with a distribution line, a closing coil and a holding coil, and the main switch is turned on by flowing a closing current through the closing coil, and the holding current is passed through the holding coil. Supplying current to the closing coil and holding coil of an automatic switch for distribution with an electromagnetic operating mechanism that keeps the switch in the on state and a manual operating mechanism that manually turns on and opens the main switch The target is a drive control circuit of an automatic switch for power distribution to be controlled.

  In the present invention, the auxiliary switch is provided so as to be mechanically interlocked with the main switch, maintains the on state when the main switch is in the open state, and turns off when the main switch is in the on state. An excitation switch that is connected in series to the switch and the auxiliary switch, maintains an on state for a certain time when the main switch is turned on, and is turned off when the certain time has elapsed, and an auxiliary switch And a rectifier for rectifying the output of the control power transformer that steps down the voltage of the distribution line. The closing coil is provided so that the output voltage of the rectifier is applied through a parallel circuit of an excitation changeover switch, an auxiliary switch and a current limiting element, and the holding coil is connected in series to the closing coil, A rectifier output voltage is applied through the coil. In the present invention, when the output voltage of the rectifier is applied to the closing coil through the current limiting element while the auxiliary switch is open, the closing current of the magnitude required for turning on the main switch is turned on. The impedance of the current limiting element is set so that it can flow through the coil.

  With the above configuration, a large closing current flows through the closing coil only until the main switch is completely turned on, and only a current limited by the current limiting element flows after the main switch has been turned on. Therefore, it is possible to reduce the burden on the control power transformer when the main switch is turned on, and it is possible to use a control power transformer having a smaller capacity than the conventional one. Therefore, it is possible to reduce the size and cost of the control power transformer. Further, since the drop in the output voltage of the control power transformer that occurs when the main switch is turned on can be reduced, it is possible to prevent the control circuit in the switch slave station from malfunctioning when the main switch is turned on.

  In addition, when configured as described above, even when the main switch is in a manually turned on state, by applying a distribution line voltage to the control power transformer, the excitation switch is turned on and the main switch is turned on. Therefore, when the restoration work is completed, the main switch that was manually turned on is shifted to the state where it is electromagnetically turned on, and the power supply of the system is removed from the mobile power generator. It is possible to cause the transformer of the power supply substation to perform the operation of switching without interruption without any trouble.

  In the above configuration, the holding coil is connected in series with the closing coil so that the output voltage of the rectifier is applied to the holding coil through the closing coil. However, the holding coil is connected in parallel to the closing coil. Then, the output voltage of the rectifier may be applied to the holding coil without going through the closing coil.

  As the current limiting element, a reactor or a resistance element may be used.

  In the present invention, when the main switch is turned on, in addition to the excitation changeover switch that keeps the on state for a certain time, the main switch is in the on state when the main switch is in the open state, and the main switch is in the on state. An auxiliary switch that is sometimes turned off and a current limiting element connected in parallel to both ends of the auxiliary switch are provided, and an excitation changeover switch and an auxiliary are connected to a closing coil to which a closing current is supplied when the main switch is turned on. Since it is configured to apply the rectified output of the control power transformer through the parallel circuit of the switch and the current limiting element, when the main switch is turned on, a large input current is applied to the input coil only for a short time until the input operation is completed. After the main switch is turned on, only the current limited by the current limiting element can flow through the closing coil.

  Therefore, according to the present invention, the burden on the control power transformer when the main switch is turned on can be reduced, and the control power transformer having a smaller capacity than the conventional one can be used. And cost reduction. Further, since the drop in the output voltage of the control power transformer that occurs when the main switch is turned on can be reduced, the possibility that the control circuit in the switch slave station malfunctions when the main switch is turned on can be eliminated.

  Further, in the present invention, even when the main switch is turned on manually, a turn-on current necessary for turning the main switch on is supplied to the making coil by applying a distribution line voltage to the control power transformer. The main switch that has been manually turned on can be shifted to the state of being electromagnetically turned on as it is, so that when the restoration work is completed, the power supply of the system is switched from the mobile power generator to the transformer of the power substation without interruption. The operation can be performed without any trouble.

It is the circuit diagram which showed the structure of one Embodiment of this invention. It is a time chart for demonstrating operation | movement of embodiment shown in FIG. It is the circuit diagram which showed the structure of other embodiment of this invention. It is the circuit diagram which showed the structure of other embodiment of this invention. It is the circuit diagram which showed the structure of the drive control circuit of the conventional automatic switch for power distribution. 6 is a time chart for explaining the operation of the drive control circuit shown in FIG. 5. It is the circuit diagram which showed the structure of the drive control circuit of the other conventional automatic switch for power distribution.

Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS.
FIG. 1 shows the configuration of the first embodiment of the present invention. In FIG. 1, 1 is an automatic switch and 2 is a switch slave station. The automatic switch 1 includes main switches Su, Sv and Sw inserted in series in U, V and W three-phase distribution lines, respectively, and a closing coil (CC) 3 which is excited when these main switches are operated. And an electromagnetic operating mechanism that performs a turning-on operation and a holding-holding operation of the main switch, an auxiliary switch 12 and a current limiting element 13 using an electromagnet having a holding coil (HC) 4 as an operation drive source. The closing coil 3 and the holding coil 4 are connected in series by commonly connecting one end of each of them, and one end of the auxiliary switch 12 is connected to the connection point of both coils. The electromagnet that constitutes the drive source of the electromagnetic operation mechanism has a return spring that urges the movable core toward the side that opens the main switch, and returns when the excitation current of the closing coil and holding coil is reduced to zero. The main switch is automatically opened by the action of the spring.

  The auxiliary switch 12 is a switch that is mechanically interlocked with the main switches Su to Sw and performs an operation opposite to that of the main switch, and maintains the ON state when the main switches Su to Sw are in the open state (OFF state). When the main switches Su to Sw are turned on (on state), they are turned off. The current limiting element 13 includes a reactor, and the current limiting element is connected in parallel to both ends of the auxiliary switch 12.

  The automatic switch 1 is also provided with a manual operation mechanism that puts the main switch into an on state and an open state by a turning operation of an operation handle that is manually operated through an operation string.

  The switch slave station 2 includes a switch 5 that is normally maintained in an ON state, and a rectifier 7 that rectifies the output of the transformer 6 when the output of the control power transformer 6 that steps down the voltage of the distribution line is input through the switch 5. And a smoothing circuit comprising a series circuit of a resistor 8 and a capacitor 9 connected between the DC output terminals of the rectifier 7 and a timer relay 10 having an exciting coil connected between the output terminals of the rectifier 7.

  In the illustrated example, the positive output terminal of the rectifier 7 is connected to the other end (terminal opposite to the holding coil 4) of the closing coil 3 in the automatic switch 1, and the negative output terminal of the rectifier 7 is Connected to the other end of the holding coil 4 in the automatic switch 1 (terminal opposite to the making coil 3), the output voltage of the rectifier 7 is applied to both ends of the series circuit of the making coil 3 and the holding coil 4. ing.

  The timer relay 10 has a normally open contact MCa, and starts a timed operation for measuring a certain time T when a voltage is applied from the control power transformer 6 to the rectifier 7 and the rectifier 7 generates a rectified output. The contact MCa is turned on, and the contact MCa is turned off when a predetermined time T has elapsed. In the present embodiment, the excitation changeover switch 11 is configured by the contact MCa. In the illustrated example, one end of the excitation changeover switch 11 is connected to the negative output terminal of the rectifier 7, and the other end of the excitation changeover switch 11 is connected to the other end of the auxiliary switch 12. Therefore, the making coil 3 is provided so that the output voltage of the rectifier 7 is applied through the parallel circuit of the excitation switch 11, the auxiliary switch 12 and the current limiting element 12, and the holding coil 4 is connected to the making coil 3. They are connected in series so that the output voltage of the rectifier 7 is applied through the input coil. The control power transformer 6 is provided outside the automatic switch 1 and is disposed in the vicinity of the switch slave station 2.

  In the normal automatic switch 1, sensors such as a current transformer for detecting the current of each phase and a zero-phase current transformer for detecting the zero-phase current are further provided. In the switch slave station 2, Although a detection unit for detecting a ground fault or a short-circuit accident is provided from the output of a sensor provided in the automatic switch, these are not shown.

  In the present embodiment, even when the output voltage of the rectifier 7 is applied to the closing coil 3 through the current limiting element 13 in a state where the auxiliary switch 12 is open, the magnitude necessary for turning on the main switches Su to Sw is large. The impedance of the current limiting element 13 is set so that the current can be supplied to the coil 3.

  In the present embodiment, the circuit in the switch slave station 2, the auxiliary switch 12, and the current limiting element 13 constitute a drive control circuit for the automatic switch. A time chart showing the operation of this drive control circuit is shown in FIG. 2A schematically shows the output voltage of the rectifier 7, and FIG. 2B shows the input currents Icc1 and Icc2 flowing through the input coil 3, and the holding current Ihc flowing through the input coil 3 into the holding coil 4. This is shown schematically. 2 (C) and 2 (D) show the on / off operation of the auxiliary switch 12 and the on / off operation of the excitation changeover switch (MCa) 11, respectively. FIG. 2 (E) shows the on / off operation of the main switches Su to Sw. Yes.

  When the main switches Su to Sw are in the open circuit state, the auxiliary switch 12 is in the on state and the current limiting element 13 is short-circuited. As shown in FIG. 2 (A), when a distribution line voltage is applied to the primary side of the control power transformer 6 at time t1 and the rectifier 7 generates an output voltage, the excitation changeover switch 11 as shown in FIG. 2 (D). 2 is turned on, and as shown in FIG. 2B, a closing current Icc1 flows from the rectifier 7 through the auxiliary switch 12 and the excitation switching switch 11 to the closing coil 3.

  At time t2, when the movable electrodes of the main switches Su to Sw come into contact with the fixed contact electrodes and the main switch is turned on, the auxiliary switch 12 is turned off as shown in FIG. 13 is released, and the current limiting element 13 is connected in series to the closing coil 3. As a result, as shown in FIG. 2B, the input current flowing through the input coil 3 is reduced to Icc2 (<Icc1).

  After the rectifier 7 generates the output voltage at time t1, when a certain time T has elapsed and time t3 is reached, the excitation changeover switch 11 is turned off as shown in FIG. A holding current Ihc is supplied to the holding coil 4 through the coil 3. The holding current Ihc indicates a current value further limited than the limited input current Icc2. While the holding current Ihc flows through the holding coil 4, the main switches Su to Sw are held in the on state. As shown in FIG. 2A, when the distribution line voltage disappears at time t4 and the output voltage of the rectifier 7 becomes zero, the holding current Ihc supplied to the holding coil 4 disappears. As shown in FIG. 2E, the main switches Su to Sw are opened, and as shown in FIG. 2C, the auxiliary switch 12 interlocked with the main switch is turned on.

  As described above, in the drive control circuit of this embodiment, the auxiliary switch is connected in series to the closing coil 3 and the current limiting element is connected to both ends of the auxiliary switch, so that the turning on of the main switches Su to Sw is completed. Until this time, the auxiliary switch is turned on and the current limiting element is short-circuited to cause a large current to flow in the making coil, and when the making operation of the main switches Su or Sw is completed, the auxiliary switch 12 is turned off to limit the current. Since the closing current flowing in the closing coil is limited by releasing the short circuit of the element, it is possible to prevent the closing coil from being magnetically saturated and an excessive charging current from flowing, and to reduce the burden on the control power transformer 6. can do. Therefore, the control power transformer 6 having a smaller capacity than the conventional one can be used, and the control power transformer can be downsized and the cost can be reduced.

  In this embodiment, the current that flows through the current limiting element 13 and the closing coil 3 when the rectifier 7 generates an output voltage with the auxiliary switch 12 open and the excitation changeover switch 11 is turned on. However, since the impedance of the current limiting element 13 is set so as to indicate the size required to turn on the main switches Su to Sw, the distribution line voltage is maintained even when the main switch is manually turned on. Is input to the rectifier 7 through the control power transformer 6, so that the manually switched main switches Su to Sw can be shifted to the electromagnetically switched state as they are. Therefore, when the restoration work for the accident section is completed, the main switch that has been manually turned on is shifted to the state in which the electromagnetic switch is turned on as it is, and the power supply of the system is switched from the mobile power generator to the transformer of the power supply substation without interruption. The operation can be performed without any trouble.

  FIG. 3 shows a second embodiment of the present invention. In the first embodiment shown in FIG. 1, the control power transformer 6 is provided outside the automatic switch 1. However, in the embodiment shown in FIG. Control power transformers 6A and 6B are provided. The first control power transformer 6A is provided so as to take in and step down the voltage between two of the three phases (between UW phases in the illustrated example) on the upstream side (substation side) of the main switches Su to Sw. The second control power transformer 6B is provided to take in and step down the voltage between two of the three phases (between the UW phases in the illustrated example) on the downstream side of the main switches Su to Sw. One end of each secondary coil of the first control power transformer 6A and the second control power transformer 6B is connected to the ground potential section. In the present embodiment, the lightning arresters LAu1 to LAw1 connected between the upstream terminals of the three-phase main switches Su to Sw and the ground, and the lightning arresters connected between the downstream terminals of the three-phase main switches and the ground. LAu2 to LAw2 are provided in the automatic switch 1 together with the control power transformers 6A and 6B.

  In the present embodiment, a power source changeover switch 14 having fixed contacts 14 a and 14 b and a movable contact 14 c that selectively contacts these fixed contacts is provided in the switch slave station 2. The other end of the secondary coil of the first control power transformer 6A provided in the automatic switch 1 is connected to one fixed contact 14a of the power switch 14 and the secondary coil of the second control power transformer 6B. Is connected to the other fixed contact 14 b of the power source switch 14. The movable contact 14c of the power switch 14 is connected to one input terminal of the rectifier 7 through the switch 5, and the other input terminal of the rectifier 7 is connected to the ground side terminal of the secondary coil of the control transformers 6A and 6B. Yes.

  Although not shown, a control unit is provided for controlling the changeover switch 14 in accordance with the presence or absence of the output voltages of the control power transformers 6A and 6B. For example, when the control power transformer 6A generates an output voltage, the control unit brings the movable contact 14c of the power switch 14 into contact with the fixed contact 14a, and passes the output voltage of the control power transformer 6A through the switch 5. When there is no output voltage of the control power transformer 6A and the output voltage of the control power transformer 6B is input to the rectifier 7, the movable contact 14c of the power switch 14 is brought into contact with the fixed contact 14b to control the power transformer 6B. The changeover switch 14 is controlled so that the output voltage is input to the rectifier 7 through the switch 5. The other configuration of the drive control circuit shown in FIG. 3 is the same as that of the embodiment shown in FIG. 1, and the operation thereof is also the same as that of the embodiment shown in FIG.

  FIG. 4 shows a third embodiment of the present invention. In this embodiment, the holding coil 4 is connected in parallel to the making coil 3 so that the output voltage of the rectifier 7 is applied without going through the making coil 3. The other points are configured in the same manner as the embodiment shown in FIG. The operation of this embodiment is the same as that of the embodiment shown in FIG. 1 except that when a holding current is passed through the holding coil 4, no current is passed through the closing coil 3.

  In each of the above embodiments, the current limiting element 12 is configured by a reactor, but the current limiting element 12 may be configured by a resistance element.

  In each of the above embodiments, when the distribution line voltage disappears and no voltage is applied from the control power transformer 6 to the rectifier 7, the holding current flowing through the holding coil 4 is immediately cut off, and the main switches Su to Sw However, the automatic switch 1 has a delay cut-off characteristic so that the main switch is immediately opened when the distribution line voltage disappears in the event of a ground fault or short circuit. Rather than when the substation circuit breaker is opened and the distribution line is set to no voltage, when a certain delay time has elapsed, the main switches Su to Sw are configured to be in an open state, The present invention can be applied without particularly changing the excitation circuit of the closing coil and the holding coil for providing the delay cutoff characteristic. As a method for providing the automatic switch 1 with a delay cutoff characteristic, for example, after flywheel diodes are connected in parallel to both ends of the closing coil 3 and both ends of the holding coil 4, respectively, and the command switch 5 is turned off. The main switches Su to Sw are opened by flowing current through the flywheel diodes connected in parallel to the making coil 3 and the holding coil 4 with the energy stored in the making coil 3 and the holding coil 4, respectively. A method of delaying the operation is known.

  In each of the embodiments described above, the main switches Su to Sw may be ones in which the fixed electrode and the movable electrode are disposed in the air. The vacuum switch in which the fixed electrode and the movable electrode are disposed in the vacuum vessel, the fixed electrode, A movable electrode may consist of a gas switch etc. which are arrange | positioned in arc-extinguishing gas.

  In each of the above-described embodiments, a timed operation is started when a voltage is applied to the distribution line and a voltage is applied from the control power transformer 6 to the rectifier 7, and during a certain period of time until the timed operation is completed. The excitation changeover switch 11 is configured by the contact MCa of the timer relay 10 that maintains the ON state. However, the excitation changeover switch is not limited to the contact of the relay, and a voltage is applied from the control power transformer 6 to the rectifier 7. Sometimes, it may consist of a timer circuit that starts a timed operation that measures a certain time T, and a semiconductor switch that remains on while the timer circuit performs a timed operation.

  The present invention provides a normally-excited automatic switch for power distribution in which a main switch is turned on by flowing a turn-on current to a turn-on coil and then a main switch is held in a turn-on state by flowing a restricted holding current to the holding coil. Can be widely applied.

DESCRIPTION OF SYMBOLS 1 Automatic switch 2 Switch sub-station 3 Input coil 4 Holding coil 5 Command switch 6, 6A, 6B Control power transformer 7 Rectifier 11 Excitation switch 12 Auxiliary switch 13 Current limiting element

Claims (4)

A main switch inserted in series with the distribution line; and a closing coil and a holding coil. The main switch is turned on by passing a closing current through the closing coil, and the holding current is passed through the holding coil. An electromagnetic operation mechanism for holding the switch in a turned-on state and a manual operation mechanism for performing a turning-on operation and an opening operation of the main switch by manual operation. A drive control circuit of an automatic switch for power distribution that controls supply,
An auxiliary switch that is provided to be mechanically interlocked with the main switch, maintains an on state when the main switch is in an open state, and is in an off state when the main switch is in an on state; ,
An excitation changeover switch connected in series to the auxiliary switch, maintaining an on state for a certain time when the main switch is turned on, and being turned off when the certain time has elapsed,
A current limiting element connected in parallel to both ends of the auxiliary switch and connected in series to the excitation changeover switch,
A rectifier that rectifies the output of the control power transformer that steps down the voltage of the distribution line;
Comprising
The closing coil is provided so that the output voltage of the rectifier is applied through the excitation changeover switch, the auxiliary switch, and a parallel circuit of a current limiting element,
The holding coil is connected to the input coil in series, and is provided so that the output voltage of the rectifier is applied through the input coil.
When the output voltage of the rectifier is applied to the closing coil through the current limiting element while the auxiliary switch is open, the closing current of the magnitude required to turn on the main switch is also applied. The impedance of the current limiting element is set so that it can flow through the coil;
The drive control circuit of the automatic switch for power distribution characterized by this. A main switch inserted in series with the distribution line; and a closing coil and a holding coil. The main switch is turned on by passing a closing current through the closing coil, and the holding current is passed through the holding coil. An electromagnetic operation mechanism for holding the switch in a turned-on state and a manual operation mechanism for performing a turning-on operation and an opening operation of the main switch by manual operation. A drive control circuit of an automatic switch for power distribution that controls supply,
An auxiliary switch that is provided to be mechanically interlocked with the main switch, maintains an on state when the main switch is in an open state, and is in an off state when the main switch is in an on state; ,
An excitation changeover switch connected in series to the auxiliary switch, maintaining an on state for a certain time when the main switch is turned on, and being turned off when the certain time has elapsed,
A current limiting element connected in parallel to both ends of the auxiliary switch and connected in series to the excitation changeover switch,
A rectifier that rectifies the output of the control power transformer that steps down the voltage of the distribution line;
Comprising
The closing coil is provided so that the output voltage of the rectifier is applied through the excitation changeover switch, the auxiliary switch, and a parallel circuit of a current limiting element,
The holding coil is connected in parallel to the making coil, and is provided so that the output voltage of the rectifier is applied without going through the making coil,
When the output voltage of the rectifier is applied to the closing coil through the current limiting element while the auxiliary switch is open, the closing current of the magnitude required to turn on the main switch is also applied. The impedance of the current limiting element is set so that it can flow through the coil;
The drive control circuit of the automatic switch for power distribution characterized by this.   The drive control circuit for an automatic switch for power distribution according to claim 1 or 2, wherein the current limiting element comprises a reactor.   The drive control circuit for an automatic switch for power distribution according to claim 1 or 2, wherein the current limiting element comprises a resistance element.

Images