JPH09282982A - Synchronous type gas-blast load breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten an arc time in breaking so as to prolong a maintenance/ inspection cycle by detecting a breaking current or a voltage waveform, and controlling to bring a fixed contact piece and a movable contact piece into contact with or separation from each other in a suction type breaking system. SOLUTION: A control circuit is constituted such that an arithmetic circuit S1 calculates a predetermined arc timing so as to send a signal to a circuit breaker CB when a current flowing in the circuit breaker CB is monitored by a current transformer C4 so that a breaking signal C0 is output from a system control disk S. A voltage waveform may be detected in place of the current. When an insulating operation rod 12, a suction piston 7 and a movable contact piece 8 are operated rightward in breaking, a pressure inside a suction chamber 11 is rapidly decreased, so that an arc generated by contact or separation between a contact piece 8 and a fixed contact piece 3 is extinguished by a gas flow. Since a time until a predetermined pressure value required for breaking is short in a suction system as compared with a buffer system, the contact piece 8 is opened by sliding by a given distance, thus shortening an arc time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synchronous gas switchgear using a suction shutoff system, and more particularly to a synchronous gas switchgear suitable for frequent opening and closing.

[0002]

2. Description of the Related Art Circuit breakers and load switches break several hundred amperes of current even when switching small currents through a capacitor for phase adjustment or a reactor circuit, and thousands of amperes when switching load currents. Then, it is necessary to cut off the current of tens of thousands of amperes. At this time, the life of the circuit breaker becomes a problem, especially for a circuit breaker that interrupts the current a number of times. This is because the contacts are consumed by the arc generated when the current is cut off. In order to extend the life of the circuit breaker and prolong the maintenance and inspection cycle, it is essential to shorten the arc time.

By the way, in a conventional puffer type gas circuit breaker, the puffer cylinder moves along with the opening and closing action of the contact, compresses the gas in the puffer chamber constituted by the puffer piston, and forms an arc. The basic idea is to blow and extinguish the arc. For this reason, the puffer pressure rises and reaches the maximum value at the end of the stroke, and the arc time is relatively long.

Various efforts have heretofore been made to shorten the arc time. An example thereof is described in Japanese Patent Laid-Open No. 3-257727. The one disclosed in Japanese Patent Laid-Open No. 3-257727 is a method of controlling the opening phase of the circuit breaker so that the so-called arc time from the opening of the circuit breaker to the current zero point becomes constant.
Here, the opening phase is set immediately after the puffer pressure rises to a predetermined pressure necessary for shutting off.

[0005]

As described in JP-A-3-257727, the arc time can be shortened by setting the opening phase, but the gas in the puffer chamber is compressed. Since this is a system, it takes time to rise to a predetermined pressure, and there is a limit to shortening the arc time.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a synchronous gas switchgear which shortens the arc time at the time of interruption and prolongs the maintenance and inspection cycle in a circuit breaker and a switchgear which require relatively frequent switching. is there.

[0007]

In order to achieve the above object, the synchronous gas switchgear of the present invention comprises a separable fixed contact and a movable contact in a container filled with arc-extinguishing gas. ,
A suction type gas switchgear comprising a suction cylinder and a suction piston for expanding the arc extinguishing gas by the opening operation of the both contacts to blow the arc extinguishing gas to the arc generated during the opening operation. Providing a control means for detecting a breaking current or voltage waveform and outputting a breaking signal, and performing control for opening and closing the fixed contact and the movable contact in synchronization with the breaking current or voltage waveform by the breaking signal. It is a feature.

Further, in the container filled with the arc-extinguishing gas, the separable fixed contact and the movable contact are expanded, and the arc-extinguishing gas is expanded by the separation operation of the contact to expand the arc-extinguishing gas. A suction-combined puffer-type gas equipped with a suction cylinder and a suction piston for spraying an arc-extinguishing gas on a generated arc, and a puffer cylinder and a piston for compressing the arc-extinguishing gas and spraying the arc-extinguishing gas on the arc. A switchgear, which is provided with control means for detecting a breaking current or voltage waveform and outputting a breaking signal, and opens the fixed contact and the movable contact in synchronization with the breaking current or voltage waveform by the breaking signal. It is characterized by performing control.

Further, the fixed contact and the movable contact are separated by the control means so as to synchronize the stroke position where the expansion pressure in the suction cylinder and the suction piston is minimum with the position where the breaking current is zero. It was done like this. Further, the shutoff signal is divided into a shutoff signal at the time of normality and a shutoff signal at the time of fault current interruption from the system control board, and is controlled so as to perform synchronous interruption at the time of normality.

[0010]

1 to 4 show an embodiment of the present invention.
This will be described with reference to FIG. FIG. 1 is a vertical cross-sectional view showing a closed state of a suction type shutoff unit according to an embodiment of the present invention, and FIG.
3 is a vertical cross-sectional view showing the cut-off state of the cut-off portion of FIG. 3, FIG. 3 is a cut-off operation characteristic diagram of the suction-type cut-off portion of this embodiment, and FIG. is there. The present embodiment is an example in which a suction type gas circuit breaker is applied as shown in FIGS. 1 and 2, and is an application example of a synchronous gas switch. Container 1 filled with arc-quenching gas such as SF ₆ gas
The shut-off portion 2 of the suction type gas circuit breaker housed inside is mainly composed of a fixed contact 3, a conductor 4, a shield 5, and an insulating support tube 6.
And a movable side including a hollow movable contact 8 fixed to the suction piston 7, a suction cylinder 9, and an insulating support cylinder 10. Here, suction piston 7
A suction chamber 11 is formed with the suction cylinder 9, and an insulating operation rod 12 is connected to the suction chamber 9. The insulated operating rod 12 is operated by an operating device (not shown). Further, the hollow portion 13 of the movable contactor 8 is provided with an air supply port 14 communicating with the suction chamber 11, and the suction cylinder 9 is provided with the suction chamber 11 and the container 1 in the latter half of the shutoff operation.
An opening 15 that communicates with the gas space inside is provided.

FIG. 4 shows a control circuit for use in the system, which is controlled by the current flowing through the circuit breaker CB. The current is monitored by the current transformer Ct and shut off from the system control board S. When the signal _Co is issued, the arithmetic circuit S1 calculates the time at which a predetermined arc time is reached and sends the interruption signal to the circuit breaker CB. Here, the case where the current is detected has been described, but it may be detected by a voltage waveform.

With this construction, the insulating operating rod 1 is operated by an operating device (not shown) in FIG.
2, by operating the suction piston 7 and the movable contactor 8 in the right direction in FIGS. 1 and 2, the horizontal axis represents time T, and the vertical axis represents the stroke characteristic showing the operation of the movable contactor 8 at the time of interruption operation. S
As can be seen from FIG. 3 in which the pressure characteristic Ps in the suction chamber 11 is shown, the pressure Ps in the suction chamber 11 rapidly decreases due to expansion. The arc generated by the separation between the fixed contact 3 and the movable contact 8 is a gas flow 16 generated by the pressure difference between the gas pressure Po in the container 1 and the pressure Ps in the suction chamber 11.
Extinguishes by spraying. In the latter half of the shutoff operation, since the suction chamber 11 and the gas space in the container 1 communicate with each other through the opening 15, the pressure Ps in the suction chamber 11 returns to the gas pressure Po in the container 1.

In the puffer type shutoff portion, the blowing pressure is maximized at the end of the stroke, while in the suction type shutoff portion, the pressure in the suction chamber formed by the suction cylinder and the suction piston is increased. It has a characteristic that the change with time is fast and the pressure difference between the gas pressure Po in the container and the pressure Ps in the suction chamber reaches the maximum value immediately after the start of the operation. By combining such characteristics with the synchronous interruption method, it becomes possible to maximize the effect of shortening the arc time required for the synchronous interruption method. This will be described in more detail with reference to FIG. 8, which shows a result of comparison of blowing pressure characteristics at the time of the breaking operation of the puffer type circuit breaker and the suction type circuit breaker by the pressure difference with the container gas space. In the pressure characteristic P1 of the puffer type circuit breaker corresponding to the stroke characteristic S, the arrival time to the predetermined pressure value Pc required for breaking is t1, whereas in the pressure characteristic P2 of the suction type circuit breaker, it is time t2. It's getting faster.
Therefore, when the circuit breaker is to be synchronously interrupted, it is necessary to adjust the opening phase so that the current zero point comes at time ts1 in the puffer breaker and at time ts2 in the suction breaker. Become. Here, since the contacts are set to open at the time Tw after sliding by a certain distance sw, the arc time is Ta1 for the puffer type circuit breaker and Ta2 for the suction type circuit breaker. . As described above, by applying the suction type circuit breaker to the synchronous circuit breaking type, it is possible to efficiently reduce the arc time, and it is possible to obtain a circuit breaker having a long maintenance and inspection cycle and improved economy.

The above-described suction-type shutoff portion can quickly achieve the blowing pressure condition required for shutoff, and as a result, the arc time can be greatly shortened. or,
Short arc achieved in the suction system interruption part by performing synchronous interruption so that the zero point of the interruption current is reached at the time t0 which is the lowest area of the pressure Ps in the suction chamber 11, that is, the maximum area of the pressure difference shown in FIG. It becomes possible to keep the time constant. At this time, since an appropriate arc time can be secured, there is an effect that it is possible to prevent re-arcing when the advance small current is interrupted or the reactor current is interrupted. As a result, it is possible to obtain a circuit breaker in which the arc time at the time of interruption is significantly shortened without impairing the reliability, and the economy of long maintenance inspection cycle is improved.

Another embodiment of the present invention will be described with reference to FIGS. FIG. 5 is a vertical cross-sectional view showing a state in which the suction / puffer type shutoff unit according to the present embodiment is shutting off, and FIG.
Characteristic diagram of the shutoff operation of the puffer type shutoff part with suction
FIG. 3 is a circuit diagram illustrating a control system of this embodiment.

As shown in FIG. 5, this embodiment is a suction combined puffer system shut-off unit in which a suction system and a puffer type shut-off unit are used in combination, and as this system, for example, Japanese Patent Publication No. 57-34616. There is one described in. As can be seen from FIG. 5 in which the shutoff portion is in the midway of shutting off, in the present embodiment, as in the embodiment mainly shown in FIG. 1, it is fixed to a container (not shown) through an insulating support member 17. Fixed contact 18, hollow movable contact 20 fixed to the suction piston 19, suction cylinder 21, insulating support tube 22,
A puffer chamber 27 is composed of an insulating operation rod 23 and a suction chamber 24, and a fixed puffer piston 25 provided above the suction cylinder 21 and a puffer cylinder 26 integrally formed with the movable contact 20. An insulating nozzle 28 and an insulating cover 29 are provided on the outer periphery of the movable contact 20.

Further, as can be seen from FIG. 7 showing the control circuit, the cutoff signal from the system control board S is divided into C1 at the normal time and C2 at the time of fault current cutoff, and only the cutoff signal C1 at the normal time is synchronously cut off. I am trying to target it. By doing this, it is possible to cut off the load current, which is the target of multiple breaks, and the small current that flows in the phase-adjustment circuit, in the minimum arc time, and the fault current in the system is bypassed by the arithmetic circuit. It is possible to shut off with.

With this configuration, the stroke characteristic S indicating the operation of the movable contactor 20 during the shutoff operation, the pressure characteristic Ps in the suction chamber 24, and the pressure in the puffer chamber 27 are plotted with the time T as the horizontal axis. As can be seen from FIG. 6 in which the characteristic Pp is plotted along the vertical axis, the pressure characteristic Pp in the puffer chamber 27 is the largest in the latter half of the stroke characteristic S as compared with the pressure characteristic Ps in the suction chamber 24. Similar to the embodiment of FIG. 1, by synchronously interrupting so that the zero point of the interrupting current is reached at time t0, which is the lowest region of the pressure Ps in the suction chamber 24, that is, the maximum region of the pressure difference in the first half of the stroke, It is possible to obtain the same effect as that of the embodiment. Further, even if the synchronous interruption fails and the arc time becomes long, the current can be interrupted by the gas blowing from the puffer chamber 27 in the latter half of the stroke, so that the reliability of the interruption performance can be improved.

[0019]

According to the present invention, in a circuit breaker used for shutting off a shunt reactor, which requires a relatively frequent switching operation, the arc time can be shortened without impairing the reliability, so that the maintenance and inspection cycle is long. It is possible to obtain a circuit breaker with improved performance.

Further, by performing the synchronous interruption so that the zero point of the interruption current is reached in the lowest region of the pressure in the suction chamber, it becomes possible to keep the short arc time achieved in the suction type interruption unit constant. At this time, since an appropriate arc time can be secured, there is an effect that it is possible to prevent re-arcing when the advance small current is interrupted or the reactor current is interrupted.

Even if the synchronous interruption fails and the arc time becomes long, the current can be interrupted by blowing gas from the puffer chamber in the latter half of the stroke, so that the reliability of the interruption performance can be improved. .

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a closed state of a suction type shutoff unit according to an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view showing a cut-off state of a cut-off portion of FIG.

FIG. 3 is a characteristic diagram of the shutoff operation of the suction type shutoff unit of the present embodiment.

FIG. 4 is a circuit diagram illustrating a control system of this embodiment.

FIG. 5 is a vertical cross-sectional view showing an intermediate state of interruption of the puffer type interception / combination type interceptor according to another embodiment of the present invention.

FIG. 6 is a characteristic diagram of the shutoff operation of the puffer type shutoff unit with suction function of FIG. 5;

FIG. 7 is a circuit diagram illustrating a control system of this embodiment.

FIG. 8 is a diagram showing a difference in characteristics between a breaking unit used in the present invention and a conventionally used breaking unit.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Container, 2 ... Blocking part, 3 ... Fixed contactor, 4 ... Conductor, 5
... Shield, 6 ... Insulating support tube, 7 ... Suction piston, 8 ...
Movable contactor, 9 ... Suction cylinder, 10 ... Insulating support cylinder, 1
1 ... Suction chamber, 12 ... Insulation operating rod, 13 ... Hollow part, 1
4 ... Air supply port, 15 ... Opening, 16 ... Gas flow, 17 ... Insulating support member, 18 ... Fixed contactor, 19 ... Suction piston, 20
... Movable contactor, 21 ... Suction cylinder, 22 ... Insulation support cylinder, 23 ... Insulation operating rod, 24 ... Suction chamber, 25 ... Fixed puffer piston, 26 ... Puffer cylinder, 27 ... Puffer chamber, 28 ... Insulation nozzle, 29 ... Insulation cover, CB
… Circuit breaker, CT… Current transformer, S… System control panel, S1…
Operation circuit, _Co , C1, C2 ... Cutoff signal.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Tohoku Hiromichi 1-1-1, Kokubuncho, Hitachi City, Ibaraki Prefecture Hitachi Co., Ltd. Kokubun Plant

Claims (4)

[Claims] 1. A container filled with an arc-extinguishing gas, in which a fixed contact and a movable contact that can be separated are opened, and the arc-extinguishing gas is expanded by the opening operation of the two contacts, so that the opening operation is performed. A suction-type gas switchgear equipped with a suction cylinder and a suction piston for spraying an arc-extinguishing gas on an arc that sometimes occurs, which is provided with a control means for detecting a breaking current or a voltage waveform and providing a breaking signal. A synchronous gas switchgear which controls to open and close the fixed contact and the movable contact in synchronization with the breaking current or voltage waveform by a signal. 2. A container filled with an arc-extinguishing gas, in which a separable fixed contact and a movable contact are separated, and the arc-extinguishing gas is expanded by the separation operation of the both contacts to perform the opening operation. A suction cylinder and a suction piston for blowing an arc-extinguishing gas to an arc that occurs at times, and a suction-combined puffer type equipped with a puffer cylinder and a piston for compressing the arc-extinguishing gas and blowing the arc-extinguishing gas to the arc. A gas switchgear, comprising control means for detecting a breaking current or voltage waveform and outputting a breaking signal, and separating the fixed contact and the movable contact in synchronization with the breaking current or voltage waveform by the breaking signal. A synchronous gas switchgear which is characterized in that it is controlled. 3. The fixed contact and the movable contact are separated by the control means so as to synchronize a stroke position where the expansion pressure in the suction cylinder and the suction piston is minimum with a position where the breaking current is zero. 3. The synchronous gas switchgear according to claim 1 or 2, wherein. 4. The cutoff signal is divided into a cutoff signal at a normal time and a cutoff signal at a fault current cutoff from a system control panel, and the control is performed so as to perform a synchronous cutoff at a normal time. 3. The synchronous gas switchgear according to any one of 3 above.