JPH0568332A - Operation system of transformer - Google Patents

Abstract

PURPOSE:To remove the unbalance in the load apportionment of a plurality of transformers in a power station for distribution, and operate only the breaker for a distribution line in that distribution line surely when a short accident occurs in any distribution line. CONSTITUTION:Parallel operation is performed by linking the secondary buses 3 and 3 of a plurality of transformers 1 with each other through a semiconductor device 6 equipped with a monitor and controller 8, and if a short accident occurs, the monitor and controller 8 turns off the semiconductor device 5 prior to a breaker for a distribution line. Hereby, for the accident current, it becomes only the current from one transformer, and the break by the breaker for a distribution line becomes possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transformer operating system in a distribution substation having a plurality of transformers.

[0002]

2. Description of the Related Art As shown in FIG. 3, in a distribution substation having two or more transformers 17, each transformer 17 supplies electric power to a plurality of distribution lines, and each transformer 17 is constantly operated. Between the secondary side busbars 13 and 13, there is an open circuit breaker for busbar communication 14
Is connected by. However, in the event of a transformer accident, the transformer will stop and then the busbar communication circuit breaker will be turned on to distribute electricity, so a power outage is required once. Further, for example, when the power demand increases in the summer, the load sharing among the transformers 17 becomes unbalanced, and the utilization factor of the transformers may decrease.
Therefore, in such a case, in order to improve the supply reliability and equalize the load sharing, it is possible to turn on the busbar breaker 14 between the transformers 17 and perform the parallel operation by the plurality of transformers 17. Conceivable.

However, in such a power distribution system that operates in parallel with a transformer, when a short-circuit accident occurs in one of the distribution lines 18, a case where a plurality of transformers 17 operate independently of the transformers 17 Since a much larger accident current will flow toward the accident point, the breaking ability of the distribution line breaker 15 installed in each distribution line may be exceeded. If the distribution line breaker 15 operates in this state, the distribution line breaker 15 may be damaged. Therefore, a method may be considered in which the circuit breaker 15 for distribution line is not operated at a certain current or more, but then the circuit breaker on the primary side of the transformer
There was a problem that the accident current was suppressed by operating 16 and the power supply to a large number of distribution lines 18 was stopped, resulting in a wide blackout section.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and improves parallel operation by a plurality of transformers in order to improve supply reliability and equalize load sharing among transformers. In addition, the present invention proposes a transformer operation system that can surely operate only the distribution line breaker of a distribution line when there is a short-circuit accident in any distribution line.

[0005]

SUMMARY OF THE INVENTION The present invention, which has been made to solve the above-mentioned problems, provides a method in which the secondary side busbars of a plurality of transformers are interconnected via a semiconductor device and the semiconductor device described above is connected. Is provided with a monitoring control unit that is always on and that turns off the semiconductor device before the distribution line breaker when there is a short-circuit accident in any distribution line.

[0006]

In the transformer operation system of the present invention having the above-described structure, the semiconductor devices are always turned on to perform the parallel operation so that the load sharing among the transformers is balanced and one transformer is operated. Even if a power plant stops due to an accident, the remaining transformers can continue power distribution. If there is a short-circuit accident in the distribution line, the monitoring control unit turns off the semiconductor device before the breaker for the distribution line, so the fault current flowing toward the fault point is only the current from one transformer. .. In this way, if the fault current is reduced to the breaking capacity of the distribution line circuit breaker or less and then the distribution line circuit breaker is operated, the blackout range is limited to the fault distribution line even when multiple transformers are operated in parallel. Can be limited to

[0007]

EXAMPLES Examples of the present invention will be described below. In FIG.
1 is two transformers of a distribution substation, 2 is a primary side circuit breaker of the transformer 1, 3 is a secondary side bus bar of the transformer 1, and 4 is a distribution line. In the present invention, between the busbars 3 and 3 of each transformer 1, instead of a conventional busbar-connecting circuit breaker, a semiconductor device 5 capable of high-speed interruption is provided.
Is connected through.

Each distribution line 4 is provided with a distribution line breaker 6, and a current transformer 7 and a zero-phase current transformer 12 on its load side. The current and the zero-phase current of each distribution line 4 are detected by the current transformer 7 and the zero-phase current transformer 12, and the output thereof is the input value of the protective relay 10 of each distribution line. Also a protective relay
The output of 10 is input to the monitoring controller 8. A semiconductor device controller 9 is connected to the monitoring controller 8, and the semiconductor device controller 9 controls the semiconductor device 5 between the bus bars 3 and 3.

The semiconductor device 5 of the embodiment is formed by connecting semiconductor elements such as thyristors in antiparallel as shown in FIG. 2, but by connecting some of them in series and parallel, the load on each thyristor is reduced. It is also possible to reduce the reliability and improve the reliability of the device.

When a short-circuit accident occurs in any one of the distribution lines 4 in the state where the transformers are operated in parallel as described above, the output from the protective relay 10 causes the semiconductor device 5 to operate before the distribution line breaker. Turn off. As a result, each of the transformers 1 and 1 enters the independent operation, and the fault current is reduced to the extent that it can be interrupted by the distribution line breaker 6. Therefore, it is possible to cut off the accident by using the distribution line breaker 6.

[0011]

INDUSTRIAL APPLICABILITY As described above, according to the present invention, in a distribution substation equipped with a plurality of transformers, the semiconductor device can be constantly turned on to perform parallel operation with a plurality of transformers. The rate can be improved. Further, even if one of the transformers is stopped due to a failure or the like during parallel operation, the remaining transformers can continue the power distribution to all the distribution lines without interruption, thereby improving the supply reliability. Moreover, when there is a short-circuit accident in any distribution line, the semiconductor device can be turned off and only the distribution line breaker of that distribution line can be operated reliably, so that only the distribution line in which the accident occurred can be separated. it can. Further, according to the present invention, it is not necessary to replace the circuit breaker for distribution line with a circuit breaker having a high breaking ability, and it is possible to make the most of the conventional equipment and reduce the equipment cost. Therefore, the present invention contributes greatly to industrial development as a transformer operation system that solves the conventional problems.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

FIG. 2 is a circuit diagram of a semiconductor device.

FIG. 3 is a circuit diagram of a conventional power distribution system.

[Explanation of symbols]

 1 Transformer 3 Bus 4 Distribution Line 5 Semiconductor Device 7 Current Transformer 8 Monitoring and Control Unit 12 Zero Phase Current Transformer

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[Procedure amendment]

[Submission date] October 13, 1992

[Procedure Amendment 1]

[Document name to be corrected] Drawing

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[Correction method] Change

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[Figure 1]

[Procedure Amendment 2]

[Document name to be corrected] Drawing

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[Correction method] Change

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[Fig. 2]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Komatsubara 3-7-1, Ichibancho, Aoba-ku, Sendai City, Miyagi Prefecture Tohoku Electric Power Co., Inc. Maruikedai 17 3 (72) Inventor Kazuaki Kato 3-150 Omoteyama, Tenpaku-ku, Aichi Prefecture Nagoya (72) Inventor Tadao Kobayashi 2-1-117 Osaki, Shinagawa-ku, Tokyo (72) Inventor Yasunobu Yanagisawa 2-17, Osaki, Shinagawa-ku, Tokyo Inside Meidensha Co., Ltd.

Claims (1)

[Claims] 1. When a short-circuit accident occurring in any of the distribution lines is detected by a current transformer and a zero-phase current transformer provided in each distribution line, between the secondary side busbars of a plurality of transformers. An operating system for a transformer, comprising: a monitoring control unit for turning off the semiconductor device connected to the circuit in the ON state before the breaker for the distribution line.