JP3292783B2 - DC circuit breaker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-excited commutation type DC circuit breaker used in a DC power transmission circuit.

[0002]

2. Description of the Related Art FIG.
FIG. 6 is a configuration diagram of a conventional DC circuit breaker disclosed in Japanese Unexamined Patent Application Publication No. 6-2006.
In FIG. 13, reference numeral 1 denotes a blocking unit, which includes a fixed contact 1a and a movable contact 1b. 2 is a reactor, 3 is a capacitor. In addition, the reactor 2 and the capacitor 3
Are connected in series to form a commutation circuit 4. The commutation circuit 4 is connected to the cutoff unit 1 in parallel. DC breaker 5 is constituted by breaking section 1 and commutation circuit 4.

FIG. 14 shows, for example, Japanese Patent Application Laid-Open No. 56-141.
FIG. 129 is another configuration diagram of the conventional DC circuit breaker shown in Japanese Patent Publication No. 129. In FIG. 14, reference numeral 6 denotes a varistor made of a zinc oxide (ZnO) element, which is connected in parallel with the cutoff unit 1.
DC breaker 7 with breaking unit 1, commutation circuit 4 and varistor 6
Is configured. 8 is a disconnecting portion.

Next, the operation will be described. 13 and 14, when the cutoff unit 1 is in the closed state, the DC current I flows through the cutoff unit 1. When the contact between the two contacts 1a and 1b of the interrupting unit 1 is opened by an interruption command, an arc is generated between the contacts 1a and 1b, and a potential difference (arc voltage) is generated between the contacts 1a and 1b. This arc voltage is
While the vibration is repeated due to a short circuit at the bent portion of the arc or the like, it increases as the separation distance between the two contacts 1a and 1b increases.

If this arc has a negative characteristic that the arc voltage decreases as the current increases, the oscillating current of the oscillating current that has begun to flow through the closed loop formed by the commutation circuit 4 and the cutoff unit 1 triggered by the above-described voltage oscillation The amplitude increases. The direction of the flow of the oscillating current flowing through the breaking unit 1 is opposite to the direction of the DC current I,
When the peak value exceeds the value of the DC current I, the current flowing through the breaking unit 1 reaches a zero point, and the current of the breaking unit 1 is cut off.

FIG. 15 shows an example in which the DC circuit breaker 5 of FIG. 13 is applied as a neutral circuit protection circuit breaker for a DC transmission circuit. In FIG. 15, 9 and 10 are converters, 11 is a main line of a DC power transmission circuit, and 12 is a neutral line.

When a ground fault occurs in the neutral line 12, a current If flows from the grounding point 13 of the converter 9 to the converter 9 from the ground fault point 13 via the ground. At this point, the DC breaker 5
Of the circuit, and the current ICB of the circuit flows through the path from the DC circuit breaker 5 to the grounding section 14 via the grounding section 15 and the ground. Then, after the arc at the ground fault point 13 is extinguished, the DC breaker 5 is shut off to return to the state before the ground fault.

FIG. 16 is an explanatory diagram showing changes in current and voltage of each part when the DC breaker 5 is cut off. In FIGS. 15 and 16, at time zero, the breaking section 1 opens and an arc is generated between the contacts 1a and 1b. As the time elapses, the arc voltage Va increases, and the oscillating current Ic increases between the arc and the commutation circuit 4. The oscillating current Ic is superimposed on the DC current I, and is interrupted when the peak value of the oscillating current Ic exceeds the value of the DC current I at time T1 and the current flowing to the interrupting unit 1 becomes zero.

After the current interruption, the DC current I flows into the capacitor 3 and the voltage of the capacitor 3 rises. Accordingly, the current flowing in the DC breaker 5 is commutated to the neutral wire 12. The current Il flowing through the neutral wire 12 and the current Ic flowing through the commutation circuit 4 repeat oscillation at a vibration frequency determined mainly by the inductance value of the neutral wire 12 and the capacitance of the capacitor 3 of the commutation circuit 4. And finally the current I in the neutral 12
1 becomes equal to the current I flowing through the converters 9 and 10, and the current Ic of the commutation circuit 4 of the DC breaker 5 becomes zero.

FIG. 17 shows an example in which the DC circuit breaker 7 shown in FIG. 14 is applied to a neutral circuit protection circuit breaker for a DC power transmission circuit. FIG.
FIG. 4 is an explanatory diagram showing changes in current and voltage of each unit when the DC breaker 7 is cut off.

In FIGS. 17 and 18, at time zero, the breaking section 1 is opened, and an arc is generated between the contacts 1a and 1b. The arc voltage Va increases with time,
The oscillating current Ic between the arc and the commutation circuit 4 increases.
The oscillating current Ic is superimposed on the DC current I, and at time T1, the peak value of the oscillating current Ic exceeds the value of the DC current I, and
When the current flowing through becomes zero, the current is cut off.

After the current is cut off by the cutoff unit 1, the voltage of the capacitor 3 rises. When the voltage reaches the limit voltage VB of the varistor 6, the current flowing through the DC breaker 7 shifts to the varistor 6. After the current IB of the varistor 6 becomes almost zero,
The voltage of the capacitor 3 starts oscillating again. The current Ic and the current Il corresponding to this vibration are respectively supplied to the capacitor 3
And the neutral wire 12.

After the DC circuit breakers 5 and 7 are shut off, FIG.
5 and the DC power transmission circuit of FIG. 17 are connected to the ground by the commutation circuit 4. Usually, the capacitor of the commutation circuit of the self-excited commutation type DC circuit breaker has a large capacitance of several μF to several tens of μF.
A large current corresponding to the voltage fluctuation of the harmonic of the converter flows, causing an induction failure.

Therefore, it is necessary to connect a disconnector in series with the commutation circuit of the DC circuit breaker and to disconnect the commutation circuit immediately after the DC circuit breaker is cut off. However, as described with reference to FIGS. 16 and 18, the oscillating current continues to flow in the commutation circuit 4 even after the current is cut off by the cutoff unit 1 of the DC circuit breakers 5 and 7.
Disconnectors without current interrupt capability cannot be opened. Therefore, the circuit is opened after waiting until the oscillating current stops and the current of the commutation circuit 4 becomes zero.

[0015] In addition, most of the ground faults of the neutral wire that require the breaking operation by the DC breaker are caused by lightning. And many of the lightning strikes are so-called multiple lightning strikes that continuously attack. For this reason, the DC circuit breaker is sometimes required to repeat the closing operation and the closing operation two to three times within a short time. Further, since the disconnecting switch cannot be opened immediately after the interruption of the DC circuit breaker, if an overvoltage enters the DC circuit breaker from a neutral line immediately after the interruption, the commutation circuit 4 is exposed to the overvoltage in the configuration of FIG. . For this reason, it is necessary that the reactor 2 and the capacitor 3 have specifications corresponding to the overvoltage. Further, in the configuration of FIG. 17, since the varistor 6 is exposed to the invading overvoltage, the varistor 6 is destroyed when energy exceeding the processing capability of the varistor 6 is injected.

If the ground fault recurs after the interruption of the DC circuit breaker and it becomes necessary to continue the closing operation, the closing operation must be performed at a sufficient time interval after the interruption to leave the commutation circuit. The resulting charge is short-circuited through a relatively small reactor, so that an inrush current flows through the capacitor of the commutation circuit. For this reason, the capacitor may be destroyed depending on the size of the residual charge of the capacitor of the commutation circuit, the capacity of the reactor, the closing phase, and the like.

[0017]

Since the conventional DC circuit breaker is configured as described above, there is a restriction on the time from the interruption of the interruption section to the opening of the commutation circuit, and the cause of the induction failure is limited. There was a problem that it was easy to occur.

Further, there is a problem that the varistor may be destroyed if an overvoltage enters from the neutral wire immediately after the cutoff and energy exceeding the processing capability of the varistor is injected.

Furthermore, if the ground fault recurs after the interruption and the closing operation is performed, the electric charge remaining in the commutation circuit is short-circuited by a relatively small reactor. Inrush current may flow and the capacitor may be destroyed. Therefore, in order to suppress the inrush current of the capacitor, it is necessary to turn on the capacitor after it has been discharged to a level that does not cause a problem. Therefore, there is a problem that the time from shutting down to turning on the capacitor cannot be reduced.

The present invention has been made in order to solve the above-mentioned problems, and a self-excited commutation method capable of preventing an induction failure, preventing a varistor from being destroyed, and shortening the time from shutoff to closing. The present invention provides a DC breaker.

[0021]

According to the present invention, a commutation circuit in which a reactor and a capacitor are connected in series is connected in parallel to a first cutoff portion having a pair of first contacts that can be mechanically connected and separated. A DC breaker that superimposes an oscillating current generated between the reactor and the capacitor on the DC current due to the arc characteristics of the first breaking portion to generate a zero point in the current flowing in the first breaking portion to cut off the current. According to claim 1,
Claim 6 will be described below.

[0022] Claim 1, the second blocking portion having a second contact pair is capable of mechanically separable in parallel circuit with the first blocking portion and the commutation circuit connected in series, the The first cut-off and the second
A varistor is connected in parallel with the first interrupter, and a closing resistor circuit in which a resistor contact having a contactable / separable third contact and a closing resistor are connected in series is connected to the first resistor. Are connected in parallel with each other so that the third contact is closed before the first contact, and the third contact is opened before the first contact.

According to a second aspect of the present invention, a parallel connection between the first cut-off portion and the commutation circuit is connected in series with a second cut-off portion having a pair of second contacts that can be mechanically connected to and separated from each other. The first cut-off and the second
A varistor is connected in parallel with the first breaking unit, and a closing resistance circuit in which a resistance contact having a contactable / separable third contact and a closing resistance are connected in series is provided. Are connected in parallel with each other, so that the third contact is closed before the second contact, and the third contact is opened before the second contact.

According to a third aspect of the present invention, a second circuit having a pair of second contacts mechanically connectable and detachable is connected in series to a parallel circuit of the first circuit and the commutation circuit. The first cut-off and the second
And a varistor were connected in parallel with the first breaking part, and a first resistance contact having a detachable third contact and a first closing resistance were connected in series. A first closing resistor circuit is connected in parallel to the first cut-off section,
A second closing resistor circuit in which a second resistor contact having a second contact and a second resistor are connected in series is connected in parallel to the second interrupter, and the third contact and the fourth contact are connected to each other. The first contact and the second contact are supplied earlier, and the third contact and the fourth contact are opened earlier than the first contact and the second contact. It was done.

A fourth aspect of the present invention is directed to the first or second aspect.
The first and second cut-off portions are arranged on the same straight line in a metallic tank filled with an insulating gas, and the closing resistance circuit is arranged in the tank.

According to a fifth aspect of the present invention, in the third aspect, the first cut-off portion and the second cut-off portion are arranged on the same straight line in the metallic tank filled with the insulating gas, and the first injection is performed. A resistor circuit and a second closing resistor circuit are arranged in a tank.

[0027] Claim 6 relates to Claim 4 or Claim 5.
Then, it is led out of the tank by the first bushing from the connection portion between the first blocking portion and the second blocking portion, and the second blocking portion is connected to the second blocking portion from the side opposite to the connection portion of the first bushing of the first blocking portion. It is led out of the tank by the bushing, and led out of the tank by the third bushing from the side of the second blocking portion opposite to the connection portion of the first bushing, and is connected to the first bushing and the second bushing. A commutation circuit is connected between the second bushing and the third
Are connected to a DC power transmission circuit.

[0028]

According to a first aspect of the present invention, there is provided a DC breaker in which a closing resistance circuit in which a resistance contact having a third contact and a closing resistance are connected in series is connected in parallel to the first breaking portion having the first contact. Connection, the third contact is turned on before the first contact, and the third contact is opened before the first contact. Is discharged in a closed loop of the capacitor, the reactor, and the closing resistance circuit, so that an inrush current at the time of closing can be suppressed.

[0029] Claim 2, the closing resistor circuit connected in series with the resistor contact and a closing resistor having a third contact connected in parallel with the second blocking portion having a second contact, the third contact The second contact is inserted before the second contact, and the third contact is
By opening the contacts before the contact of the above, the charge of the capacitor of the commutation circuit is
Since the discharge is performed in the closed loop of the closing resistance circuit, the neutral line, and the return path to the ground, the inrush current at the time of closing can be suppressed.

In a third aspect, a first closing resistance circuit in which a first resistance contact having a third contact and a first closing resistance are connected in series is provided as a first breaking section having the first contact. And a second closing resistor circuit in which a second resistor contact having a fourth contact and a second resistor are connected in series with each other and connected in parallel to a second interrupter having the second contact. , The third contact and the fourth contact are supplied before the first contact and the second contact, and the third contact and the fourth contact are opened first. As a result, the charge of the capacitor of the commutation circuit is reduced by the capacitor, the reactor, and the first closing resistance circuit,
Since the discharge is performed in a closed loop including the capacitor, the reactor, the second closing resistance circuit, the neutral line, and the return path to the ground, the inrush current at the time of closing can be suppressed.

A fourth aspect of the present invention is directed to the first or second aspect.
Te, a first blocking portion and the second blocking portions arranged on the same straight line in the tank, by placing the closing resistor circuit to the tank, the connection between each other can be performed in the tank, simple configuration become.

According to a fifth aspect of the present invention, in the third aspect, the first breaking part and the second breaking part are arranged on the same straight line in the tank, and the first closing resistance circuit and the second closing resistance circuit are connected to each other. By arranging in the tank, the connection between them can be made in the tank, so that the configuration is simplified.

According to a sixth aspect of the present invention, the first bushing and the second bushing are respectively provided for deriving from the first and second blocking portions.
And a third bushing are provided, and a commutation circuit is connected between the first bushing and the second bushing at both ends of the first cut-off portion, and the second bushing and the third bushing are respectively provided. By connecting to the DC power transmission circuit, the commutation circuit can be arranged outside the tank.

[0034]

EXAMPLES Reference Example 1 FIG . Hereinafter, Embodiment 1 of the present invention will be described. FIG. 1 is a configuration diagram in a case where the DC breaker is applied as a neutral line protection circuit breaker of a DC power transmission circuit. In FIG. 1, 1-4,
6, 9 to 12, 14, and 15 are the same as the conventional ones.
Reference numeral 16 denotes a cutoff unit including a fixed contact 16a and a movable contact 16b, which are connected in series to a parallel circuit of the cutoff unit 1 and the commutation circuit 4. Reference numeral 17 denotes a metallic tank in which an insulating gas of SF6 is sealed, and both shut-off portions 1 and 16 are arranged on the same straight line.

Reference numeral 18 denotes an operating device which mechanically connects and drives the movable contacts 1b and 16b of the blocking portions 1 and 16. Reference numeral 19 denotes a bushing fixed to the tank 17, which is led out of the tank 17 from a connection between the two shut-off portions 1 and 16. Reference numeral 20 denotes a bushing.
Derived from the opposite side. Reference numeral 21 denotes a bushing, which is led out from a side of the blocking unit 16 opposite to the bushing 19.

FIG. 2 is an explanatory diagram showing changes in current and voltage of each part when the DC breaker is cut off. In FIG. 1 and FIG. 2, when a ground fault occurs in the neutral wire 12, the shutoff commands cause the shutoff sections 1 and 16 to be opened almost simultaneously. Thereafter, the current interruption of the interruption unit 1 is performed at time T1 in the same manner as in the conventional case. During this time, an arc exists in the cutoff section 16.

After the cutoff unit 1 cuts off the current, the current I of the DC transmission circuit flows into the capacitor 3 of the commutation circuit 4,
The voltage Vc of the capacitor increases. And the commutation circuit 4
The current Ic that has flowed through is gradually commutated to the neutral line 12. At this time, the current Ic flowing through the capacitor 3 and the current Il flowing through the neutral wire 12 repeat oscillation at a frequency substantially determined by the capacitance of the capacitor 3 and the inductance value of the neutral wire 12. Then, the current I flowing through the breaking unit 16 is
CB goes to zero.

Further, the current Il flowing through the neutral line 12 is settled down to the current I of the DC power transmission circuit. And the blocking unit 1
The current ICB flowing through 6 reaches a zero point at time T2 after a １ ／ cycle of the above-mentioned oscillation frequency has elapsed. As a general value of each circuit constant, if the capacitance of the capacitor of the commutation circuit of the DC circuit breaker of the self-excited commutation method is 10 μF to 100 μF, and the inductance value of the neutral wire is 50 mH to 100 mH, the above oscillation frequency becomes 50 Hz to 225 Hz.

Therefore, the load current of the DC power transmission circuit is set to 3 KA.
, The current change rate at the current zero point (di / d
t) is 0.94 A / μs to 4.24 A / μs.
This current change rate is a value that can be interrupted for a puffer type gas circuit breaker using SF6 gas as an arc-extinguishing medium, for example. Therefore, for example, when a puffer type gas circuit breaker is applied to the cutoff section, the current ICB flowing through the capacitor 3 of the commutation circuit 4 is cut off at time T2. At that time, the entire current I flowing through the DC power transmission circuit flows through the neutral line 12, and returns to the state before the occurrence of the ground fault. At this time, the capacitor 3
Is the maximum voltage.

From the point of view of construction, both bushings 19 and 20
The commutation circuit 4 arranged outside the tank 17 is connected between them. This facilitates connection between the cutoff unit 1 and the commutation circuit 4. Further, by removing the bushing 19 and leaving only the bushings 20 and 21 at both ends, 2
It can be applied as a breaking unit of a DC breaker having a breaking point configuration.

FIG. 3 is an explanatory diagram showing the timing when the shut-off unit 1 is preliminarily turned on. 1 and 3,
Surge impedance of commutation circuit 4 (square root of L / C)
Is large and the inrush current at the time of closing is small, the electric charge of the capacitor 3 of the commutation circuit 4 is extinguished and attenuated by the resistance in the closed loop constituted by the cutoff unit 1 and the commutation circuit 4. Therefore, there is no effect on the DC transmission system.

FIG. 4 is an explanatory diagram showing the timing when the shut-off section 16 is preliminarily closed. This case is applied to a case where the inrush current is large when the cutoff section 1 precedes the input. 1 and 4, for example, the capacitance of the capacitor 3 of the commutation circuit 4 is 50 μF, the residual voltage is 30 kV,
Assuming that the inductance of the neutral wire 12 is 50 mH, the peak of the rush current when the cutoff unit 16 is turned on is 950 A. It is applied when the effect of this current on the DC transmission system is not a problem.

As shown in FIGS. 3 and 4, even if either of the interrupting sections 1 and 16 is preliminarily turned on, both of the interrupting sections 1 and 16 are opened at the time of interrupting. As a result, since the capacitor 3 of the commutation circuit 4 is disconnected from the DC power transmission circuit, even if, for example, an electric shock is applied to the neutral line 12 immediately after the interruption, the capacitor 3 is insulated by the interruption unit 16. The dielectric strength can be reduced. Therefore, the size of the capacitor 3 can be reduced.

Reference Example 2 In the above-described reference example 1 , since both of the breaking portions 1 and 16 are simultaneously opened during the breaking operation, and the breaking portion 16 breaks later than the breaking portion 1, the breaking portion 16 can break up to an arc time longer than the breaking portion 1. Performance is required. Therefore, by configuring the breaking unit 16 to be opened later than the breaking unit 1, the arc time of the breaking unit 16 is reduced. Therefore, the breaking unit 16 having the same arc time width as that of the breaking unit 1 can be applied, and the consumption of the arc contact is reduced.

Embodiment 1 FIG. 5 is a configuration diagram of the first embodiment . FIG. 6 is an explanatory diagram showing the timing at the time of insertion. In FIG. 5, reference numeral 22 denotes a resistance contact, which includes a fixed contact 22a and a movable contact 22b. 23 is a closing resistance. A closing resistor circuit 24 is configured as a series circuit in which a resistance contact 22 and a closing resistor 23 are connected in series. The closing resistance circuit 24 is connected in parallel with the cutoff unit 1, and the two contacts 22 a of the resistance contact 22 are connected.
And 22b are thrown before the shutoffs 1 and 16. When the contact is opened, the resistance contact 2 is provided before both the breaking parts 1 and 16.
2 is configured to open.

Next, the operation will be described. 5 and 6
After the resistance contact 22 is turned on, the electric charge of the capacitor 3 of the commutation circuit 4 is discharged in a closed loop of the capacitor 3, the reactor 2 and the closing resistance circuit 24. After the two shutoff units 1 and 16 are turned on, discharge is performed in the closed loop of the capacitor 3, the reactor 2, the shutoff unit 16, the neutral wire 12, and the ground return path. Immediately after the input, the charge of the capacitor 3 of the commutation circuit 4
4, the rush current can be suppressed.

Further, at the time of breaking, both breaking sections 1 and 16 are opened. As a result, since the capacitor 3 of the commutation circuit 4 is disconnected from the DC power transmission circuit, even if, for example, an electric shock is applied to the neutral line 12 immediately after the interruption, the capacitor 3 is insulated by the interruption unit 16. The dielectric strength can be reduced. Therefore, the size of the capacitor 3 can be reduced.

Embodiment 2 FIG . FIG. 7 is a configuration diagram of the second embodiment . FIG. 8 is an explanatory diagram showing the timing at the time of closing. In FIG. 7, reference numeral 25 denotes a resistance contact, which comprises a fixed contact 25a and a movable contact 25b. 26 is a closing resistance. The resistance contact 25 and the closing resistance 26 constitute a closing resistance circuit 27. Then, the closing resistance circuit 27 is connected in parallel with the breaking section 16, and both contacts 25 a and 25 b of the resistance contact 25 are closed before the breaking sections 1 and 16. Also, when the contact is opened, the resistance contact 25 is opened prior to the breaking sections 1 and 16.

Next, the operation will be described. 7 and 8
After the resistance contact 25 is turned on, the electric charge of the capacitor 3 of the commutation circuit 4
Discharge occurs in the closed loop of the neutral wire 12 and the ground return.
After the shutoff sections 1 and 16 are turned on, the closed loop including the capacitor 3, the reactor 2, and the shutoff section 1 and the condenser 3, the reactor 2, the shutoff section 16, the neutral line 12, and the ground return path are formed. Discharge occurs in a closed loop.

As described above, since the charge of the capacitor 3 of the commutation circuit 4 is discharged in a closed loop immediately after being turned on, the rush current can be suppressed. Further, at the time of breaking, both breaking sections 1 and 16 are opened. As a result, since the capacitor 3 of the commutation circuit 4 is disconnected from the DC power transmission circuit, even if, for example, an electric shock is applied to the neutral line 12 immediately after the interruption, the capacitor 3 is insulated by the interruption unit 16. The dielectric strength can be reduced. Therefore, the size of the capacitor 3 can be reduced.

Embodiment 3 FIG . FIG. 9 is a configuration diagram of the third embodiment . FIG. 10 is an explanatory diagram showing the timing at the time of insertion. FIG. 9 shows a combination of the configuration of FIG. 5 of the first embodiment and the configuration of FIG. 7 of the second embodiment .
In FIG. 9, both resistance contacts 22 and 25 are closed prior to both interruption parts 1 and 16. Then, at the time of interruption, both resistance contacts 22 and 25 are configured to open before the interruption parts 1 and 16.

Next, the operation will be described. 9 and 1
At 0, after both resistance contacts 22 and 25 are closed,
The electric charge of the capacitor 3 is discharged by the closed loop of the capacitor 3, the reactor 2, and the closing resistor circuit 24, and the closed loop of the capacitor 3, the reactor 2, the closing resistor circuit 27, the neutral line 12, and the ground return. Then, both blocking parts 1 and 16
Is charged, the electric charge of the capacitor 3 is discharged by the closed loop of the capacitor 3, the reactor 2, and the cutoff unit 1, and the closed loop of the capacitor 3, the reactor 2, the cutoff unit 16, the neutral line 12, and the ground return path. .

As described above, the charge of the capacitor 3 of the commutation circuit 4 is discharged through the closing resistors 23 and 26 in a closed loop immediately after the closing, so that the rush current is suppressed. Further, at the time of breaking, both breaking sections 1 and 16 are opened. As a result, since the capacitor 3 of the commutation circuit 4 is disconnected from the DC power transmission circuit, even if, for example, an electric shock is applied to the neutral line 12 immediately after the interruption, the capacitor 3 is insulated by the interruption unit 16. The dielectric strength can be reduced. Therefore, the size of the capacitor 3 can be reduced.

In each of the first to third embodiments, the most preferable configuration is selected in consideration of the magnitude of the surge impedance of the commutation circuit, the influence on the DC power transmission circuit, and the like.

Embodiment 4 FIG . FIG. 11 is a configuration diagram of the fourth embodiment . FIG. 12 is an explanatory diagram showing the state of the voltage and current of each part at the time of interruption. 11 and 12, when a ground fault occurs in the neutral wire 12,
In response to the shutoff command, the shutoff units 1 and 16 are opened almost simultaneously. Thereafter, the current interruption of the interruption unit 1 is performed at time T1 in the same manner as in the conventional case. During this time, an arc exists in the cutoff section 16.

After the cutoff unit 1 cuts off the current, the current I of the DC transmission circuit flows into the capacitor 3 of the commutation circuit 4,
The capacitor 3 is charged and the voltage rises. When the voltage of the capacitor 3 reaches the limit voltage of the varistor 6,
The current flowing into the capacitor 3 flows through the varistor 6, and the voltage of the capacitor 3 is kept almost constant.

When the current flowing through the breaking unit 1 reaches a zero point,
The current is cut off at time T1. At this time, the entire current I of the DC power transmission circuit is flowing through the neutral wire 12. Then, the current flowing through each part becomes the state before the accident of the neutral wire 12. By the operation of the varistor 6, the time interval from the current interruption at the time T1 of the interruption unit 1 to the current interruption at the time T2 of the interruption unit 16 becomes longer than that in the case where the varistor 6 is not provided. Therefore, when the opening times of both the breaking portions 1 and 16 are the same, the arc time of the breaking portion 16 becomes longer. Therefore,
By delaying the opening timing of the interrupting section 16 from the opening time of the interrupting section 1 by the length of the arc time,
The arc time of both breaking parts 1 and 16 can be made equal.

Immediately after the interruptions of the interruption sections 1 and 16, the commutation circuit 4 responds to the overvoltage entering the neutral line 12 by the interruption section 1.
6, the dielectric strength of the commutation circuit 4 can be reduced, and the size can be reduced. Further, since the varistor 6 is also insulated by the blocking portion 16, the processing capability of the varistor can be reduced, and the size can be reduced.

Reference Examples 1 and 2 and Examples 1 to 2
In Section 4 , a self-excited commutation type DC circuit breaker was described.
The same effect can be expected even when applied to a DC circuit breaker of a forced commutation type in which the capacitance of the capacitor 3 for the commutation circuit is smaller than that of the self-excited commutation type.

[0060]

According to a first aspect of the present invention, a closing resistor circuit in which a resistance contact having a third contact and a closing resistor are connected in series is connected in parallel to a first breaking portion having the first contact. ,
Since the third contact is turned on before the first contact and the third contact is opened before the first contact, the charge of the capacitor of the commutation circuit is reduced by the capacitor,
Since the discharge is performed in the closed loop of the reactor and the closing resistance circuit, the rush current at the time of closing is suppressed, and the time interval between the closing operation and the breaking operation can be shortened.

[0061] Claim 2, the closing resistor circuit connected in series with the resistor contact and a closing resistor having a third contact connected in parallel with the second blocking portion having a second contact, the third contact The second contact is inserted before the second contact, and the third contact is
By opening the contacts before the contact of the above, the charge of the capacitor of the commutation circuit is
Since the discharging is performed in the closed loop of the closing resistance circuit, the neutral line, and the return path to the ground, the rush current at the time of closing is suppressed, and the time interval between the closing operation and the breaking operation can be shortened.

In a third aspect, a first closing resistor circuit having a first contact is provided with a first closing resistor circuit in which a first resistance contact having a third contact and a first closing resistor are connected in series. And a second closing resistor circuit in which a second resistor contact having a fourth contact and a second resistor are connected in series with each other and connected in parallel to a second interrupter having the second contact. , The third contact and the fourth contact are supplied before the first contact and the second contact, and the third contact and the fourth contact are opened first. As a result, the charge of the capacitor of the commutation circuit is reduced by the capacitor, the reactor, and the first closing resistance circuit,
Since the discharge is performed in a closed loop including the capacitor, the reactor, the second closing resistance circuit, the neutral wire, and the return path to the ground, the inrush current at the time of closing is suppressed, and the time interval between the closing operation and the breaking operation can be shortened.

A fourth aspect is the first or second aspect.
Te, a first blocking portion and the second blocking portions arranged on the same straight line in the tank, by placing the closing resistor circuit to the tank, the connection between each other can be performed in the tank, simple configuration become.

According to a fifth aspect, in the third aspect, the first breaking part and the second breaking part are arranged on the same straight line in the tank, and the first closing resistance circuit, the second closing resistance circuit, By arranging in the tank, the connection between them can be made in the tank, so that the configuration is simplified.

In the present invention , the first bushing and the second bushing are respectively provided for leading out from the first blocking portion and the second blocking portion.
And a third bushing are provided, and a commutation circuit is connected between the first bushing and the second bushing at both ends of the first cut-off portion, and the second bushing and the third bushing are respectively provided. By connecting to the DC power transmission circuit, the commutation circuit can be arranged outside the tank.

[Brief description of the drawings]

FIG. 1 is a configuration diagram in which a first embodiment of the present invention is applied to a DC power transmission circuit.

FIG. 2 is an explanatory diagram showing current and voltage of each unit at the time of interruption in FIG.

FIG. 3 is an explanatory diagram showing a timing at the time of closing of a blocking unit in FIG. 1;

FIG. 4 is an explanatory diagram showing timing at the time of closing of a blocking unit.

FIG. 5 is a configuration diagram in which the first embodiment is applied to a DC power transmission circuit.

FIG. 6 is an explanatory diagram showing a timing at the time of turning on a breaking unit and a resistance contact in FIG. 5;

FIG. 7 is a configuration diagram in which the second embodiment is applied to a DC power transmission circuit.

FIG. 8 is an explanatory diagram showing a timing at the time of closing of a breaking unit and a resistance contact in FIG. 7;

FIG. 9 is a configuration diagram in which Embodiment 3 is applied to a DC power transmission circuit.

FIG. 10 is an explanatory diagram showing a timing at the time of closing of a breaking unit and a resistance contact in FIG. 9;

FIG. 11 is a configuration diagram in which Embodiment 4 is applied to a DC power transmission circuit.

FIG. 12 is an explanatory diagram showing currents and voltages of respective units at the time of interruption in FIG. 11;

FIG. 13 is a configuration diagram showing a conventional DC breaker.

FIG. 14 is another configuration diagram showing a conventional DC circuit breaker.

FIG. 15 is a configuration diagram in which a conventional circuit breaker is applied to a DC power transmission circuit.

FIG. 16 is an explanatory diagram showing currents and voltages of respective parts at the time of interruption in FIG.

FIG. 17 is a configuration diagram in which another conventional circuit breaker is applied to a DC power transmission circuit.

FIG. 18 is an explanatory diagram showing currents and voltages of respective units at the time of interruption in FIG.

[Explanation of symbols] 1, 16 cut-off section, 2 reactor, 3 condenser,
4 commutation circuit, 6 varistor, 17 tank, 19-2
1 bushing, 22, 25 resistance contact, 23, 26
Resistance, 24, 27 closing resistance circuit.

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Naoaki Takeharu 3-3-22 Nakanoshima, Kita-ku, Osaka City Inside Kansai Electric Power Co., Inc. (72) Inventor Masahiro Hirose 2-5 Marunouchi, Takamatsu City, Kagawa Prefecture Shikoku Electric Power Co., Inc. (72) Inventor Yoshinobu Makino 6-15-1, Ginza, Chuo-ku, Tokyo Inside Power Development Co., Ltd. (72) Inventor Takeshi Yonezawa 8-1-1 Tsukaguchi Honcho, Amagasaki City Mitsubishi Electric Corporation Itami Works ( 56) References JP-A-5-234471 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01H 33/59

Claims (6)

(57) [Claims] 1. A method in which a reactor and a capacitor are connected in series.
A pair of first contacts that can mechanically contact and separate the commutation circuit
Connected in parallel with the first interrupting section having
Depending on the arc characteristics, the reactor and the capacitor
Is superimposed on the DC current,
A zero point is generated in the current flowing through the interrupting section 1 to interrupt the current.
In the DC breaker, the first breaker is provided.
And a pair that can be mechanically connected to and separated from the parallel circuit of the commutation circuit
A second interrupter having a second contactor is connected in series,
Mechanically connecting the first and second blocking parts
And the varistor is connected in parallel with the first interrupting section,
Series with a resistive contact with a functional third contact and a closing resistor
The connected closing resistor circuit is connected in parallel to the first breaking section
Then, the third contact is input before the first contact.
And the third contact is opened before the first contact.
DC cut-off characterized by being configured to be poled
vessel. 2. A method in which a reactor and a capacitor are connected in series.
A pair of first contacts that can mechanically contact and separate the commutation circuit
Connected in parallel with the first interrupting section having
Depending on the arc characteristics, the reactor and the capacitor
Is superimposed on the DC current,
A zero point is generated in the current flowing through the interrupting section 1 to interrupt the current.
In the DC breaker, the first breaker is provided.
And a pair that can be mechanically connected to and separated from the parallel circuit of the commutation circuit
A second interrupter having a second contactor is connected in series,
Mechanically connecting the first and second blocking parts
And the varistor is connected in parallel with the first interrupting section,
Series with a resistive contact having an active third contact and a closing resistor
The connected closing resistor circuit is connected in parallel to the second breaking section
And the third contact is input before the second contact.
And the third contact is opened before the second contact.
DC cut-off characterized by being configured to be poled
vessel. 3. A series connection of a reactor and a capacitor.
A pair of first contacts that can mechanically contact and separate the commutation circuit
Parallel connected to the first blocking portion having, of the first cut-off portion
Depending on the arc characteristics, the reactor and the capacitor
Is superimposed on the DC current,
A zero point is generated in the current flowing through the interrupting section 1 to interrupt the current.
In the DC breaker, the first breaker is provided.
And a pair that can be mechanically connected to and separated from the parallel circuit of the commutation circuit
A second interrupter having a second contactor is connected in series,
Mechanically connecting the first and second blocking parts
And the varistor is connected in parallel with the first interrupting section,
A first resistive contact having a third contact and a first dosing
A first closing resistor circuit in which a resistor and a resistor are connected in series is connected to the first
It has a fourth contact that is connected in parallel to the interrupter and that can be separated
A second throw having a second resistance contact and a second resistance connected in series
An input resistance circuit is connected in parallel to the second cutoff section,
And the fourth contact are in contact with the first contact.
The second contact is input earlier than the third contact,
The fourth contact is in contact with the first contact and the second contact.
It is characterized that it is configured to open the electrode earlier with the
DC circuit breaker. 4. The insulating material according to claim 1, wherein
The first line on the same straight line in the metallic tank filled with gas
And the second interrupting section are arranged, and the closing resistance circuit is
A DC circuit breaker, which is arranged in the tank. 5. The method according to claim 3, wherein the insulating gas is filled.
The first cutout and the first
2 interrupting sections, and a first closing resistor circuit and a second throw-in circuit.
Characterized in that an input resistance circuit is arranged in the tank.
DC breaker. 6. The method according to claim 4, wherein
A first bushing from a connection between the blocking portion and the second blocking portion;
To the outside of the tank at the first
At the second bushing from the opposite side of the bushing connection
Leading to the outside of the tank, and
The third bushing from the side opposite to the connection of the first bushing
To the outside of the tank with the first bushing.
A commutation circuit is connected between the first bushing and the second bushing.
The second bushing and the third bushing are each
And connected to a DC power transmission circuit.
DC breaker.