JPH06103856A - Gas circuit breaker - Google Patents

Abstract

PURPOSE:To suppress drop of the system voltage due to energizing rush current when a large capacity transformer is switched in, by specifying the resistance value of a resistor, and restricting the preceding switch-on time of a resistor contact. CONSTITUTION:A gas blast circuit breaker is equipped with a breaking part 18 having a pair of contact pieces 11, 12 connectible within a vessel filled with an insulative arc-extinguishing gas and a switch-on device consisting of a resistor couple 17 and a resistor contact 20 in connection with the contact pieces 11, 12. Therein the resistor 17 has a resistance value of 500OMEGA and controls the energizing rush current of a transformer. The preceding switch-on time of the resistor contact 20 to be put on precedingly to the contact pieces 11, 12 of the breaking part is made exceeding 12ms. This accomplishes prevention of a momentary voltage drop by suppressing the energizing rush current when large capacity transformer is switched in.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas circuit breaker, and more particularly to a gas circuit breaker connected to a transformer having a relatively large capacity installed in a substation installed at a terminal of a power system. .

[0002]

2. Description of the Related Art Generally, as a gas circuit breaker for a power transmission line, at least a pair of contacts which can be brought into contact with and separated from a container filled with an insulating arc-extinguishing gas is provided in order to suppress a switching surge generated at the time of its opening / closing operation. For example, a gas circuit breaker provided with a breaking unit having the breaking unit and a closing resistance device electrically connected in parallel to the breaking unit and including a resistance contact and a resistor that is closed prior to the breaking unit is known. It is described in Japanese Patent Laid-Open No. 1-313823 and is actually used in the 362 kV system, but the resistance value of the resistor that suppresses the switching surge is about 500Ω, and the resistance contact is inserted prior to the breaking unit. The preceding charging time is about 10 ms. In such a power line gas circuit breaker, the frequency of the switching surge generated during its switching operation is very high, and the duration is short, so that the switching surge can be sufficiently suppressed with the relatively short preceding time as described above. Can be suppressed.

[0003]

By the way, there is a transformer with a relatively large capacity installed in a substation located at the end of the system far from the power source end of the power system. At this time, the exciting inductance of the iron core in the transformer becomes small, and a phenomenon in which a large amount of current instantaneously flows in, a so-called exciting inrush current generation phenomenon occurs.
On the secondary side of the transformer, the occurrence of this phenomenon causes the voltage to drop instantaneously and the generation of harmonic currents. As a result, malfunctions such as the above-mentioned voltage drop of the electromagnetic switch of the consumer, abnormal noise of the transformer, flicker of the fluorescent lamp, trip of the customer's SELVIUS pump, stop of the ropeway, etc. occur. For this reason, it is desirable to install an uninterruptible power supply on the customer side as a measure against an instantaneous voltage drop, but this will increase the cost. Also, on the power company side,
In order not to cause trouble during pressurization, we are trying to make the voltage higher than the steady voltage during pressurization and make it about the steady voltage even if the voltage drops due to the inrush current generation phenomenon, but the labor and operational constraints required for this Is something that cannot be ignored. On the other hand, a gas circuit breaker having the above-mentioned closing resistance device is connected to the transformer, and the transformer is pressurized by closing the gas circuit breaker. It can be suppressed by the body,
Actually, the desired result was not obtained.

An object of the present invention is to provide a gas circuit breaker capable of suppressing a decrease in system voltage due to an exciting inrush current when a large capacity transformer is pressurized.

[0005]

In order to achieve the above object, the present invention provides a shutoff portion having at least a pair of contacting elements that can be brought into and out of contact with a container filled with an insulating arc-quenching gas, and the pair of A closing resistance device composed of a resistance contact and a resistance contact that is electrically connected in parallel to the contact and is inserted prior to the pair of contacts, and is provided on either one of the primary side and the secondary side of the transformer. In the connected gas circuit breaker, the resistance value of the resistor is set to 500 Ω or more in order to suppress the exciting inrush current of the transformer, and the resistance contact is applied prior to the pair of contacts. The feature is that the time is 12 ms or more.

[0006]

As described above, in the gas circuit breaker according to the present invention, the pre-closing time of the resistance contact which is closed prior to the contactor of the breaker is set to 12 ms or more, so that 500 Ω or more is applied to the main circuit prior to the closing of the breaker. The resistor can be inserted for 12 ms or more, which can suppress the inrush current of the large-capacity transformer during pressurization and prevent an instantaneous voltage drop.

[0007]

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 2 is a circuit diagram showing a power system to which a gas circuit breaker according to an embodiment of the present invention is applied. For example, 154 kV class buses 2 and 3 are connected to the power source 1 via a connection bus 4. To this bus 3, a large capacity transformer 6, a circuit breaker 7 connected to its primary side, and a secondary side are connected. A 77 kV class bus bar 5 is connected via a circuit breaker 8 connected to. A plurality of lines 9 leading to general loads are connected to the bus bar 5. The circuit breaker 7 connected to the primary side of the transformer 6 or the circuit breaker 8 connected to the secondary side of the transformer 6 described above is shown in FIGS.
However, for convenience of explanation, only the circuit breaker 7 will be described here.

FIG. 3 shows an equivalent circuit diagram of a circuit breaker 7 according to an embodiment of the present invention. It is electrically parallel to a circuit breaker 18 having at least a pair of contacts, a resistor 17 and a resistor. A closing resistance device consisting of a contact 20 is connected. The resistance contact 20 of the closing resistance device is turned on prior to the closing of the breaking unit 18 for a predetermined preceding closing time described later, and thereafter, until the breaking unit 18 is closed, that is, only the preceding closing time is described later. The resistor 17 having the resistance value to be inserted is inserted into the main circuit.

FIG. 1 shows a schematic configuration diagram of a circuit breaker 7 constructed based on such an equivalent circuit diagram. The blocking unit 18 is composed of a fixed contact 11 and a movable contact 12, the fixed contact 11 is connected to one terminal 10 of the main circuit, and the movable contact 12 is connected to the other terminal of the main circuit via a current collector 13. It is connected to 14. In addition, the movable contact 12 has an insulating nozzle 2
2 and the puffer cylinder 23 are connected to each other, and are connected to the operating device 15 via an insulating rod (not shown). The puffer cylinder 23 is a piston 2 slidably fitted
2 forms a puffer chamber 16 and the operating device 1
The arc-extinguishing gas in the puffer chamber 16 is compressed by the shut-off operation of No. 5, and the compressed gas is guided by the insulating nozzle 22 to generate an arc caused by the separation between the contacts 11 and 12.
It is sprayed on Ku and extinguishes it. As can be seen from this description, the breaker 18 has a configuration known as a puffer type gas circuit breaker. Electrically and mechanically connecting one end of the conductive support arm 25 to the puffer cylinder 23,
A movable resistance contact 26 is attached to its free end, and a follow-up type fixed resistance contact 27 is provided so as to face the movable resistance contact 26, and the closing resistance contact 20 shown in FIG. ing. The follow-up type fixed resistance contact 27 is configured as shown in an enlarged sectional view of FIG. That is, the cylinder 33 is fixed to the tip of the insulating rod 32, the follow-up fixed resistance contact 27 is slidably arranged in the cylinder 33, and the follow-up fixed resistance contact 27 is constantly moved by the spring 31 to the movable resistance contact 26 side. Urging to
A dashpot mechanism 34 that gradually releases the reaction force on the spring 31 is formed between the cylinder 33 and the follow-up type fixed resistance contact 27. A plurality of annular resistor elements 35 are inserted into the insulating rod 32, and the outer periphery of the resistor element 35 is covered with an insulating pipe 36 to form the resistor 17.

When the circuit breaker is open, the follow-up type fixed resistance contact 27 is already moved to the movable resistance contact 26 side by the spring 31 while resisting the dashpot mechanism 34. The separation distance between the contact 26 and the follow-up type fixed resistance contact 27 is smaller than the distance between the fixed contact 11 and the movable contact 12 of the breaker 18. Therefore, when the closing operation is performed by the operating device 15, the movable resistance contact 26 connected to the puffer cylinder 23 first contacts the follow-up type fixed resistance contact 27 prior to the contact between the fixed contact 11 and the movable contact 12. At this time, the resistor 17 is inserted in the main circuit. On the other hand, when the breaking operation is performed, the follow-up type fixed resistance contact 27 is closed by the spring 31.
Is going to be driven to the movable resistance contact 26 side by
Since this drive is gradually performed by the dashpot mechanism 34, the fixed contact 11 and the movable contact 1 of the blocking portion 18 are
It will be separated prior to the separation of 2.

As described above, when the movable resistance contact 26 comes into contact with the follow-up type fixed resistance contact 27, the voltage is applied to the transformer 6 shown in FIG. 1 and the exciting current of the transformer begins to flow. The current is limited by the resistor 17 of the closing resistance device, and the exciting current becomes small. After that, when the closing operation is further advanced, the movable resistance contact 26 shown in FIG. 4 drives the follow-up fixed resistance contact 27 further to the left while resisting the spring 31, while the movable contactor 12 of the breaking portion 18 moves. Fixed contact 1
1 and the resistor 17 is short-circuited. The time from the contact between the movable resistance contact 26 of the closing resistance device and the follow-up type fixed resistance contact 27 until the contact between the movable contact 12 of the breaker 18 and the fixed contact 11 is the so-called preceding closing time. This advance charging time can be determined as follows. That is, it is assumed that the closing resistance type gas circuit breaker 7 is actually installed on the primary side of the transformer 6 of the system in which the voltage drop occurs due to the exciting inrush current when the transformer 6 is pressurized.
The system analysis during pressurization is performed, and the voltage drop when the preceding charging time and the resistance value are changed is calculated, and the combination that produces the effect is calculated.

FIG. 5 shows the relationship between the preceding closing time and the voltage drop obtained by the system analysis using the model system shown in FIG. 1, and the resistance value is 2000Ω. As can be seen from the figure, when the pre-charging time is 12 ms or more, the voltage drop tends to be remarkably suppressed, specifically, the voltage drop can be reduced to 2% or less, and the voltage should be extremely stable. You can As described above, in the gas circuit breaker provided with the closing resistance device for suppressing the switching surge, the preceding closing time of the closing resistance device is about 10 ms, which is higher than that in the case of using such a gas circuit breaker. The decrease is significantly suppressed. As described above, the preceding closing time of the gas circuit breaker according to the present embodiment is as long as 12 ms, while the preceding closing time of the closing resistance device used for the gas circuit breaker for suppressing the switching surge is about 10 ms. , This is the blocking unit 1
This can be realized by making the separation distance between the movable resistance contact 26 and the follow-up type fixed resistance contact 27 smaller than the separation distance between the fixed contact 11 and the movable contact 12 of FIG.

FIG. 6 shows the relationship between the resistance value and the voltage drop obtained by the system analysis using the model system shown in FIG.
The advance charging time is 14 ms. As can be seen from the figure, when the resistance value is 500Ω or more, the voltage drop can be reduced to 4% or less, but when the resistance value is large, a large current is generated when the movable contact 12 and the fixed contact 11 of the breaking unit 18 come into contact with each other. Since it flows, it is better to specify the upper limit. Therefore, if the resistance value is 1000 to 4500Ω, the voltage drop can be 3% or less, and preferably the resistance value is 1500 to 2500.
When it is Ω, the voltage drop can be 2% or less. Such a resistance value is large in comparison with the resistance value of the closing resistance device used in the gas circuit breaker for suppressing the switching surge of about 500Ω, but the resistance value of each resistor element 35 is one. It can be dealt with by increasing the value.

[0014]

As described above, the present invention is a gas circuit breaker having a closing resistance device having a resistance value of 500Ω or more, preferably 1500 to 2500Ω, and a preceding closing time of 12 ms or more. It is possible to almost eliminate the voltage drop due to the exciting inrush current at the time of pressure, and to prevent various troubles of the customer due to the instantaneous voltage drop.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a gas circuit breaker according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of a power system to which a gas circuit breaker according to an embodiment of the present invention is applied.

FIG. 3 is an equivalent circuit diagram of the gas circuit breaker shown in FIG.

FIG. 4 is an enlarged cross-sectional view of a main part of the gas circuit breaker shown in FIG. 1 in an open circuit state.

FIG. 5 is a characteristic diagram showing a relationship between a preceding charging time and a voltage drop.

FIG. 6 is a characteristic diagram showing a relationship between a resistance value and a voltage drop.

[Explanation of symbols]

 6 Transformer 7 Gas Circuit Breaker 8 Gas Circuit Breaker 11 Fixed Contact 12 Moving Contact 17 Resistor 18 Breaker 20 Closing Resistance Contact 26 Moving Resistance Contact 27 Follow-up Fixed Resistance Contact

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Katsuya Kuga 1-1-1, Kokubun-cho, Hitachi-shi, Ibaraki Inside Kokubun factory, Hitachi, Ltd. (72) Inventor Yukio Uchida 1-1-1, Kokubun-cho, Hitachi-shi, Ibaraki No. 1 Stock Company, Hitachi, Ltd., Kokubun Plant (72) Inventor Akiei Ogawa 1 Higashishinmachi, Higashi-ku, Nagoya-shi, Aichi Chubu Electric Power Co., Inc.

Claims (3)

[Claims] 1. A breaker having at least a pair of contacts that can be brought into and out of contact with a container filled with an insulating arc-extinguishing gas, and the pair of contacts electrically connected in parallel to the pair of contacts. In a gas circuit breaker connected to either one of the primary side and the secondary side of the transformer, the resistance value of the resistor is the resistance value of the resistor. Is 500Ω or more in order to suppress the magnetizing inrush current of the transformer, and the resistance contact has a pre-closing time of 12 ms or more prior to the pair of contacts. 2. The gas circuit breaker according to claim 1, wherein the resistance value of the resistor is 1000 to 4500Ω. 3. The gas circuit breaker according to claim 1, wherein the resistance value of the resistor is 1500 to 2500Ω.