JPH0755026B2 - How to check the operation of the uninterruptible switching device for distribution lines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a distribution line for checking the operation of a semiconductor switch in a state of being connected in parallel with a section switch or an interconnection switch of an uninterruptible switching device. The present invention relates to a method for checking the operation of an uninterruptible switching device.

B. Outline of the Invention A zero-phase current detector is provided in the uninterruptible switching device, and the switch inside the switch and the semiconductor switch is connected in parallel with the section switch or the interconnection switch in parallel with the switch. A gate command is given to the gate control circuit to turn on each phase anti-conductor anti-parallel pair of the semiconductor switch for a minute time for each phase, and operation of the semiconductor anti-parallel pair for each phase is confirmed by confirming zero-phase current. It is to confirm.

C. Conventional technology As an uninterruptible switching method for switching the system of a section of a high-voltage distribution line (hereinafter referred to as "distribution line"), as shown in Fig. 3, two distribution lines A and B are temporarily looped. For example, there is a method of switching the depth of the section B _R to the distribution line A of another system.

A problem in forming a loop is that a cross current (loop current) flows. Therefore, the following method has been conventionally used.

(1) Insert a voltage / phase adjuster and match the voltage and phase of both distribution lines before making a loop.

(2) A loop is formed, the loop current is detected, and if the current value is within the breaking capability of the new loop point switching switch, it is automatically opened, and if it exceeds the blocking capability, the switch is locked so that it cannot be opened.

However, since the method (1) uses the voltage / phase adjuster, the device becomes large and heavy, and the transportation to the insertion point is not easy. Further, the method (2) has a problem that, when a cross current flows and is locked, the feeder breaker trips due to overcurrent.

In order to solve such problems, the applicant first
We proposed an uninterruptible switching device that can switch distribution lines without interruption without the need for adjustment and large-scale equipment such as a phase adjuster, and without the feeder breaker tripping due to overcurrent. (Japanese Patent Application No. 1-181988).

The circuit of this uninterruptible switching device is shown in FIG.

In FIG. 4, S is an uninterruptible switching device, 1 is a semiconductor switch composed of thyristor anti-parallel pair 1a, 1b, 1c connected in parallel with interconnection switch Q or section switch P, and 2 is a semiconductor switch 1 Switch connected in series with the switch, 3 is the switching target section
Instantaneous voltage drop detection circuit that detects the voltage drop of B _R and outputs the gate-on command, 4 is the instantaneous current increase detection circuit that detects the current increase during looping and outputs the gate-off command, and 5 is the detection circuit 3 or 4 This is a gate control circuit for a thyristor that controls the closing and opening of a thyristor parallel circuit in response to a gate-on / gate-off command and a manual or remote on / off command.

This uninterruptible switching device is used, for example, as follows.

(1) When connecting the section B _R to the distribution line A, the open state uninterruptible switching device S is connected in parallel with the open state interconnection switch Q (after the connection, the switch 2 in S is in advance Close it) and open the section switch P to separate the section B _R. As a result, the voltage in the section B _R drops, but the instantaneous voltage drop detection circuit 3 detects this voltage drop and outputs a gate-on command to the gate control circuit 4 to instantly close the thyristor anti-parallel circuit 1. Therefore, the section B _R can be switched to the distribution line A without interruption.

(2) When disconnecting the section B _R from the distribution line A, the uninterruptible switching device S is connected in parallel with the interconnecting switch Q in the closed state to close it, and the interconnecting switch Q opens. Then, when the section switch P is closed, a loop is formed and the current increases, so that the instantaneous current increase detection circuit 4 outputs a gate-off command to the gate control circuit 5 and the thyristor anti-parallel circuit 1a.
Instantly open 1c. Therefore, the section B _R can be returned from the distribution line A to the distribution line B without interruption.

D. Problems to be Solved by the Invention The connection of the uninterruptible switching device is not always installed immediately before switching the system of the section, and in some cases,
May be installed many days in advance. Also, if the price of uninterruptible switching equipment goes down in the future, not only will it be installed and used instantly, but it will also be installed permanently in parallel with each section switch or interconnection switch, and used when necessary. It is also expected.

In this case, if the gate circuit of the thyristor of the semiconductor switch is broken when switching is attempted and the thyristor cannot be turned on, a power failure occurs in the section to be switched.

The present invention has been made in view of such problems, and an object thereof is to provide an uninterruptible switching device for a distribution line capable of confirming that a semiconductor switch is surely turned on immediately before switching between sections. It is to provide a method of confirming the operation of.

E. Means for Solving the Problem In order to achieve the above object, the operation confirmation method of the uninterruptible switching device of the distribution line in the present invention, a series circuit of a switch and a semiconductor switch consisting of a semiconductor anti-parallel pair of each phase And a zero control current detector that detects a zero phase current flowing in the series circuit in an uninterruptible switching device that includes a gate control circuit that outputs a gate signal to the semiconductor switch, and the series circuit is a section switch or In the state of being connected in parallel with the interconnection switch, the switches of the series circuit are first closed, and then the gate control circuit is given a gate-on command for turning on each phase semiconductor parallel pair within 0.3 seconds for each phase, By confirming the zero-phase current by the zero-phase current detection, the operation of the semiconductor parallel pair is confirmed for each phase.

F. Action When a gate signal is applied to the gate control circuit for a minute time for each phase, if each phase semiconductor parallel pair of the semiconductor switch is normal, it is turned on for a minute time for each phase. When the switch of the series circuit is closed and each phase semiconductor parallel pair is turned on for only one phase for a minute time, a zero-phase current flows between the two distribution line systems for a minute time via this one-phase semiconductor parallel pair. . Therefore, if the zero-phase current is confirmed by the zero-phase current detector, the operation of each phase semiconductor parallel pair can be confirmed for each phase.

G. Example An example of the present invention will be described with reference to FIGS. 1 and 2. The same components as those shown in FIGS. 3 and 4 of the related art are designated by the same reference numerals, and their duplicated description will be omitted.

In FIG. 1, reference numeral 6 is a zero-phase current detector connected to a zero-phase current transformer ZCT provided in the circuit of the semiconductor switch 1 and capable of detecting a zero-phase current within 0.3 seconds.

First, the switch 2 in the uninterruptible switching device S is closed. next,
A certain one phase of the semiconductor switch 1, for example, a C-phase thyristor anti-parallel pair 1c is manually turned on by giving a gate-on command within 0.3 seconds to the gate drive circuit 5.

The high-voltage distribution system is not grounded, but in reality there is an impedance in the third place of the grounding transformer in the substation, and if a ground fault occurs, a _zero- phase current I ₀ will flow in this circuit, resulting in high resistance grounding. It becomes a system. The value obtained by converting the impedance of the third-order grounding transformer to the primary side is defined as the neutral-phase zero-phase impedance Zn, and the impedance of the distribution line and the ground capacitance are ignored, and the thyristor antiparallel pair 1c for one phase is turned on. Second equivalent circuit
Shown in the figure.

If there is a phase difference between the two systems, the zero phase current as shown by the broken line
I ₀ occurs. Therefore, by detecting the presence or absence of the zero-phase current I ₀ by the zero-phase current detector 6 provided in the uninterruptible switching device S, it can be confirmed that the thyristor antiparallel pair 1c is operating normally.

After this confirmation is completed, another thyristor anti-parallel pair 1a is turned on in the same manner, and the operation is checked by detecting the zero-equivalent current I _{0. After} that, the thyristor anti-parallel pair 1b is also checked in the same manner.

The reason for using the gate-on command within 0.3 seconds for the above check is to prevent the protection relay, which has a normal operation time limit of about 0.5 seconds in the substation, from operating due to the zero-phase current I ₀ .

H. Effect of the Invention Since the present invention is configured as described above, it has the following effects.

It is possible to check the operation of the uninterruptible switching device of the distribution line while it is connected to the section switch or interconnection switch without affecting other parts immediately before use. It is possible to prevent the occurrence of a power failure accident due to operation.

[Brief description of drawings]

FIGS. 1 and 2 relate to an embodiment of the present invention. FIG. 1 is a block circuit diagram of an uninterruptible switching device, and FIG. 2 is an equivalent circuit diagram between two systems when the operation of the device is confirmed. .
FIG. 3 is a block circuit diagram of a power distribution system to which an uninterruptible switching device is connected, and FIG. 4 is a block circuit diagram of a conventional uninterruptible switching device. S: uninterruptible switching device, 1 ... semiconductor switch, 3 ...
Instantaneous voltage drop detection circuit, 4 ... Instantaneous current increase detection circuit,
5 ... Gate control circuit, 6 ... Zero-phase current detection circuit.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Ryumi Maeda 2109 Yashima Nishimachi, Takamatsu City, Kagawa 8 Shikoku Research Institute (72) Inventor Masato Fuchikawa 2109 8 Yashima Nishimachi, Takamatsu City, Kagawa Shikoku Research Institute (72) Inventor Yuichi Manabe 2109, Yashima Nishimachi, Takamatsu City, Kagawa 8 Stock Company Shikoku Research Institute (72) Inventor Yasuo Kataoka 2-1-117 Osaki, Shinagawa-ku, Tokyo Stock Company Shameidensha In (72) Inventor, Akira Nakamura, 2-17, Osaki, Shinagawa-ku, Tokyo Inside Meidensha Co., Ltd.

Claims (1)

[Claims] 1. An uninterruptible switching device comprising a series circuit of a switch and a semiconductor switch composed of a semiconductor anti-parallel pair for each phase, and a gate control circuit for outputting a gate signal to the semiconductor switch. A zero-phase current detector for detecting a zero-phase current is provided, and in a state where the series circuit is connected in parallel with a section switch or an interconnection switch, first the switches of the series circuit are closed, and then the gate control circuit. A gate-on command for turning on each phase semiconductor parallel pair for each phase for a minute time, and confirming the zero-phase current by the zero-phase current detection to confirm the operation of the semiconductor parallel pair for each phase. How to check the operation of the uninterruptible switching device of the distribution line.