JPH0520984A - Resistance breaking type circuit breaker - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a highly reliable resistance breaker type circuit breaker capable of preventing unbreakable accidents. [Structure] Main shutoff unit 1 consisting of a buffer type gas shutoff unit
In the resistance interruption type circuit breaker, in which resistance interruption sections 2A and 2B formed of buffer type gas interruption sections are connected in series with A and 1B, and interruption resistors 3A and 3B are connected in parallel with the main interruption sections 1A and 1B, respectively. The resistance breaking units 2A, 2B have a breaking ability of a main breaking current, which is a current to be broken without passing through the breaking resistors 3A, 3B, so as to have a breaking ability.
It has a diameter equal to or larger than the diameter of the buffer cylinder.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resistance breaking type circuit breaker, and more particularly to a resistance breaking type circuit breaker having a resistance breaking unit connected in series with a breaking resistor.

[0002]

2. Description of the Related Art As a conventional resistance breaking type circuit breaker, there is known an air circuit breaker adopting a resistance breaking type in order to reduce the voltage rise rate of the transient recovery voltage at the time of breaking the current, and also has excellent breaking performance. In the gas circuit breaker, it is considered that the reduced cutoff method is effective for reducing the switching surge level in the UHV transmission system of 1000 kV class where the operating voltage is very high.

A circuit configuration shown in FIGS. 4 and 5 is adopted for such a resistance interruption type circuit breaker. That is, as shown in FIG. 2, the breaking resistor 3 and the resistance breaking unit 2 are connected in series, and the main breaking unit 1 is connected in parallel to them, or
Further, as shown in FIG. 3, the main breaking unit 1 and the resistance breaking unit 2 are connected in series, and the breaking resistor 3 is connected in parallel with the main breaking unit 1. The operation characteristics of both configurations are as shown in FIG. That is, assuming that the stroke characteristic of the main breaking unit 1 is S ₁ , the stroke characteristic of the resistance breaking unit 2 is S ₂ , and the current to be broken is I, the main breaking unit 1 in the closed state C first opens and opens. The state O is entered, and the main breaking current I _c that has been flowing through the main breaking portion 1 as a current to be broken by this operation is diverted to the breaking resistor 3 at the current zero point t ₁ and flows as the resistance current I _r , After the current zero point t ₁ , the resistance cutoff portion 2 changes from the closed state C to the open state O, and the resistance current I _r is cut off at the current zero point t ₂ to enter the cutoff state.

As can be seen from the above description, in the conventional resistance breaking type circuit breaker, the main breaking unit 1 has the main breaking current I _c.
In addition to the load current cutoff performance, the fault current cutoff performance is also required. Therefore, the current cutoff capacity must be increased.
Since it suffices to interrupt the resistance current I _r limited by the interrupting resistor 3, the current interrupting capacity is relatively small. Therefore, in the buffer type gas circuit breaker adopting the circuit configuration shown in FIG. 4, there is disclosed in JP-A-58-51426.
As shown in the publication, the diameter of the buffer cylinder, which is related to the current interruption capacity, is larger in the main interruption section than in the resistance interruption section.

[0005]

SUMMARY OF THE INVENTION As described above, UHV
When the gas circuit breaker used in the power transmission system is of the resistance cutoff type, the heat generation amount of the resistor with respect to the same resistance value is proportional to the square of the voltage, so the heat resistance of the cutoff resistor becomes severe.
Of course, the breaking resistor is designed so that it can sufficiently withstand the normal operating conditions, but in the unlikely event that the breaking resistor is damaged due to mechanical or thermal causes, a short circuit current will flow due to a flashover. or, or when or thermal runaway, for those whose main cutoff current I _c flows through the resistance circuit breaking portion, can not be shut off this is a resistance circuit breaking portion, the risk of leading to the final cut-off impossible accident has been made.

An object of the present invention is to provide a highly reliable resistance breaker type circuit breaker capable of preventing unbreakable accidents.

[0007]

In order to achieve the above object, the present invention provides a main breaking unit having a breaking ability for a main breaking current, and is connected in parallel with the main breaking unit and commutated by its open circuit. In a resistance breaking type circuit breaker comprising a breaking resistor and a resistance breaking unit connected in series with a parallel circuit of the breaking resistor and the main breaking unit, the ability to break the main breaking current in the resistance breaking unit. Is provided so that when the breaking resistor is damaged and thermal runaway occurs, the main breaking current is cut off by the resistance breaking unit.

[0008]

In the resistance interrupting type circuit breaker of the present invention, the resistance interrupting portion has a main interrupting current interrupting ability larger than the interrupting ability of the resistance current limited by the interrupting resistor, that is, in the system configuration. Since it has the ability to independently cut off a specific blocking duty determined, even if thermal runaway or the like occurs in the blocking resistor, the main blocking current can be blocked by the resistance blocking section. Moreover, since the resistance breaking unit finally becomes a breaking unit that cuts off the current, the main breaking current can be broken even if an abnormality occurs in the main breaking unit, and the resistance breaking unit has a reliability determined by itself. It will be.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is an equivalent circuit diagram of a resistance breaking type circuit breaker according to an embodiment of the present invention. The main breaking sections 1A and 1B having the breaking ability of the main breaking current are constituted by two series breaking points, and the resistance breaking sections 2A and 2B having the breaking ability of the main breaking current.
Is also composed of two series cutoff points. Both main blocking section 1
Breaking resistors 3A and 3B are connected in parallel with A and 1B, respectively, while voltage dividing capacitors 4A and 4B are connected in parallel with the resistance breaking units 2A and 2B, respectively.

FIG. 1 shows the configuration of a resistance interrupting type circuit breaker based on this circuit diagram. 550 for the main breaker 1A, 1B
A link mechanism 1 which is a battery type gas breaker developed for a kV single-break circuit breaker, in which the central bracket 15 is supported by an insulating cylinder 16 and is connected to a movable contactor described later.
0A and 10B are connected to a common insulating operation rod 14 positioned inside the insulating cylinder 16 and are opened / closed by a common operating device 11 via the insulating operation rod 14. This main breaker 1
Breaking resistors 3A, 3B electrically in parallel with A, 1B
Are connected, and the central portion thereof is connected via a connecting conductor 17 fixed to the bracket 15. Also, the resistance breaker 2
A and 2B are made up of a buffer type gas shutoff unit having the same configuration as the main shutoff units 1A and 1B, and are opened / closed by a common operating device 18, and the voltage dividing capacitors 4A and 4A are connected to the resistance shutoff units 2A and 2B. 4B are electrically connected in parallel. The main breakers 1A and 1B and the resistance breakers 2A and 2B are electrically connected in series by a conductor 20 supported by an insulator 9. Each of these breakers is housed in a grounded container 6 filled with arc-extinguishing gas 5 and connected to central conductors 8A, 8B of bushings 7A, 7B to form a resistance breaker.

The buffer type gas cutoff portion constituting the main cutoff portions 1A and 1B and the resistance cutoff portions 2A and 2B will be described with reference to FIG. The fixed contact 26 is composed of a fixed arc contact 21 and a fixed main contact 24 provided so as to surround the fixed arc contact 21, and as shown in FIG.
It is supported by an insulator 19 which is supported and fixed to. The movable contact 23 facing the fixed contact 26 includes a movable arc contact 22 that contacts the fixed arc contact 21 and a movable main contact 25 that contacts the fixed main contact 24. The children 22 and 25 are attached to the buffer cylinder 27. An insulating nozzle 32 provided so as to surround both arc contacts 21 and 22 is also attached to the buffer cylinder 27. Puffer cylinder 27
Is slidably supported by a piston 29 fixed to the above-mentioned bracket 15 to form a buffer chamber 30. The buffer cylinder 27 is connected to the link mechanism 10A shown in FIG. 1 via a shaft 28.

The figure shows the closed state, in which the fixed arc contact 21 and the movable arc contact 22, and the fixed main contact 24 and the movable main contact 25 are in contact with each other. However, when a cutoff command is given to the operating device 11 shown in FIG.
The movable portion of the shutoff portion represented by the buffer cylinder 27 is driven to the right in the figure via the insulating operation rod 14 and the link mechanism 10A, and the arc extinguishing gas in the buffer chamber 30 is compressed in association with this operation, and First, the movable main contact 25 is separated from the fixed main contact 24, and then the movable arc contact 22 is separated from the fixed arc contact 21 to generate an arc. By this time, the movable arc contact 22 is compressed in the buffer chamber 30. The arc-extinguishing gas is guided by the insulating nozzle 32 and sprayed on the arc to extinguish it.

In the breaking operation as the resistance breaking type circuit breaker shown in FIG. 1, first, a breaking command is given to the operating device 11,
The main shut-off portions 1A and 1B are opened with operating characteristics such as the stroke S ₁ shown in FIG. As a result, the main interruption current I _c of the current I to be interrupted at the time point t ₁ is interrupted, and the current I to be interrupted is commutated to the series circuit of the interruption resistors 3A and 3B and the resistance interruption units 2A and 2B. . The cutoff command given to the operating device 11 is also given to the operating device 18 via a delay circuit, the details of which are omitted.
A and 2B are separated by operating characteristics such as the stroke S ₂ in FIG. A current I to be interrupted flowing through the resistance interrupters 2A and 2B
Is the resistance current I _{r of} FIG. 6 due to the breaking resistors 3A and 3B.
As described above, it is cut off at the current zero point at time t ₂ . The voltage applied to the resistance cutoff portions 2A and 2B during and after the cutoff of the current is the voltage dividing capacitor 4
A, 4B, while averaged by the main breaker 1A, 1B
In B, since the breaking resistors 3A and 3B are connected in parallel, the voltage averaging effect can be obtained by the breaking resistors 3A and 3B.

During this interruption operation, the interruption resistors 3A, 3
After the main breakers 1A and 1B are opened due to thermal runaway of B or an abnormality in the main breakers 1A and 1B, the resistance breakers 2A and 2B are separated.
To, blocking resistor 3A, as the main shut-off current I _c not be influenced by connexion limit to 3B flows, resistance circuit breaking portion 2A, since 2B has a cut-off capability of the main shut-off current I _c, this It can be cut off and reliability can be improved.
On the other hand, in the closing operation, a closing command is given to the operating device 18 to close the resistance breaking units 2A and 2B, and then a closing command is given to the operating device 11 via a delay circuit (not shown) to make the main breaking unit 1.
This is done by closing A and 1B.

FIG. 7 is a vertical sectional front view showing a resistance breaking type circuit breaker according to another embodiment of the present invention. In the embodiment shown in FIG. 1, both terminals of the resistance breaking type circuit breaker are connected to the bushing 7A,
7B, but in the present embodiment, both ends of the grounding container 6 are hermetically sealed by insulating spacers 12A and 12B, and the adjacent gas compartments 13A and 13B are connected via the central conductor.
1 are connected to the central conductors 8A and 8B, and other components that are the same as those in FIG. With such a configuration, it can be used as a circuit breaker for a gas insulated switchgear.

Looking at the breaking performance required for each breaking portion, the resistance breaking portions 2A, 2B are required to individually break the fault current, so that the breaking current and the recovery voltage are both large current and high voltage. Required. On the other hand, the breaking duty in the main breaking portions 1A and 1B is slightly easier than the resistance breaking portions 2A and 2B because the recovery voltage at the time of breaking the current is reduced by the small current breaking duty due to the effect of the parallel resistance. Therefore, when constructing such a resistance breaker type circuit breaker, the resistance breaker sections 2A and 2B having the same or higher breaking performance than the main breaker sections 1A and 1B are applied. This is because when the buffer type gas blocking section known as a large capacity circuit breaker is applied to each blocking section, comparing the diameters of the buffer cylinders 27 that directly reflect the blocking performance, the resistance blocking sections 2A and 2B are the main blocking sections. 1A, 1B having the same or larger diameter is used, and the operating device 18 for the resistance breaking portions 2A, 2B has the same or larger operating force as the operating device for the main breaking portions 1A, 1B. .

In the above embodiment, the operating device 11
The cutoff command given to the operating device 18 is passed through the delay circuit.
It is also provided to the cutoff resistors 3A, 3B.
When the outage is shut down because the thermal duty of the system is severe and the switching surge level is relatively low and there is no need to cut off the resistance, a signal indicating that it is the outage is received from the system monitoring device. If the interruption command is directly given to the operating device 18 without passing through the delay circuit, the interruption can be performed without supplying the main interruption current to the interruption resistors 3A and 3B.

[0018]

As described above, according to the present invention, the main cutoff that flows without passing through the cutoff resistor to the resistance cutoff unit connected in series in the parallel circuit of the main cutoff unit and the cutoff resistor. Since the current interruption performance is provided, even if an abnormality of the main interruption part or a thermal runaway of the interruption resistor occurs, an interruption failure is not caused, and a highly reliable resistance interruption type circuit breaker can be obtained.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a resistance breaking type circuit breaker according to an embodiment of the present invention.

FIG. 2 is an equivalent circuit diagram of the resistance interruption type circuit breaker shown in FIG.

FIG. 3 is an enlarged view of a main part of FIG.

FIG. 4 is an equivalent circuit diagram of a commonly known resistance interrupt type circuit breaker.

FIG. 5 is an equivalent circuit diagram of another commonly known resistance interrupting type circuit breaker.

FIG. 6 is a characteristic diagram showing the relationship between the stroke of each breaking unit of the resistance breaking type circuit breaker and the current to be broken.

FIG. 7 is a vertical cross-sectional view of a resistance breaking type circuit breaker according to another embodiment of the present invention.

[Explanation of symbols]

1A, 1B main interruption part 2A, 2B resistance breaker 3A, 3B breaking resistor 11,18 Operating device

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Osamu Koyanagi             4026 Kujimachi, Hitachi City, Ibaraki Japan             Tachi Works Hitachi Research Laboratory (72) Inventor Yukio Kurosawa             4026 Kujimachi, Hitachi City, Ibaraki Japan             Tachi Works Hitachi Research Laboratory

Claims (4)

[Claims] 1. A resistance breaking circuit breaker comprising a breaking resistor and a resistance breaking unit connected in series, and a main breaking unit connected in parallel with the breaking resistor, wherein the resistance breaking unit is a main breaking unit. A resistance breaking type circuit breaker, which is configured to have a current breaking ability. 2. The resistance breaking type circuit breaker according to claim 1, wherein the resistance breaking unit has a breaking performance that is substantially equal to or higher than that of the main breaking unit. 3. The resistor according to claim 1, wherein the main cutoff portion and the resistance cutoff portion are constituted by a cut-off type cutoff portion having a pusher cylinder for compressing an arc-extinguishing gas in connection with a cutoff operation. A resistance breaking type circuit breaker characterized in that the buffer cylinder of the breaking portion has a diameter substantially equal to or larger than that of the buffer cylinder of the main breaking portion. 4. The operating device for the main breaking unit according to claim 3, wherein the main breaking unit and the resistance breaking unit each have an operating device for performing an opening / closing operation. A resistance interrupting type circuit breaker, characterized in that it is configured to receive the interrupting command given to the via a delay circuit.