JPH06269128A - Power-supply-line changeover apparatus in three-phase distribution line - Google Patents

Abstract

PURPOSE:To easily change over one side of a single-phase two-wire power supply line in a three-phase ditribution line to the other unconnected phase without a service interruption in a construction work section. CONSTITUTION:Out of a single-phase two-wire power supply line 2, a bypass line 7 is connected in parallel to a connection line 2b to be separated, the connection line 2b is cut between connecting points 7a, 7b, and a power supply circuit is formed of the bypass line 7. In addition, a branch line 9 in which a short- circuit switch 9 in an open state has been installed is connected across one unconnected phase and a single-phase load 3. In succession, when the branch line 9 is closed by the short-circuit switch 9 in the branch line 8, the connection line 2b is short-circuited with the branch line 8, a fuse 6 is blown, the bypass line 7 is separate electrically, and a single-phase two-wire power supply line 8 is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a feed line switching device for a three-phase distribution line.

[0002]

2. Description of the Related Art In a three-phase distribution line, various single-phase loads are connected between two appropriate phases to form a power supply line. When these power supply lines are concentrated on a specific phase, the load currents in each phase are unbalanced, causing a voltage drop on the consumer side and a load on the generator motor on the supply side. For this reason,
Conventionally, load of each phase is balanced by switching the power supply line in the system to another phase that is not connected at the location.

[0003]

In order to perform the switching work of the power supply circuit, the connection line connected to one phase to be disconnected (hereinafter referred to as "separation line") is switched to another phase which is not yet connected. In order to connect, it was necessary to put the power distribution line in the construction section into a power failure state, and it took time to restart power supply in the construction section.

Therefore, the present invention is intended to provide a power supply line switching device which can easily switch the work section without causing a power failure.

[0005]

In order to achieve the above object, according to the present invention, a bypass line for connecting a fuse in parallel to a connection line to be disconnected, and an unconnected one-phase and single-phase load are connected. It has a branch line with a short-circuit switch in an open state.

[0006]

Before the line is switched, a single-phase two-wire type power supply line for connecting a single-phase load to two phases of the three-phase distribution line is formed. To switch the disconnection line in this state while the line is live,
The bypass line is connected in parallel to the connection line to be separated. Further, a branch line provided with a short-circuit switch in an open state is connected between the unconnected one-phase load and the single-phase load.

After the connection between the bypass line and the branch line is completed, the separation line is cut between the connection points of the bypass line,
A power supply circuit is formed by connecting the bypass line to the disconnection line. Then, the branch line is closed by the short-circuit switch of the branch line. Then, the switching line and the branch line are short-circuited, the fuse connected in series to the bypass line is blown, and the bypass line is electrically disconnected. At the same time, a single-phase two-wire type power supply line is formed by the branch line.

[0008]

As described above, according to the present invention, the bypass line connecting the fuse in parallel to the disconnected connection line and the short-circuit in the open state between the unconnected one-phase and single-phase loads. Since the branch line provided with the switch is provided, it is possible to switch the power feeding line to the other phase by simply closing the short-circuit switch in the open state under the live line state.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS. As shown by the solid line in FIG. 3, A, B,
The single-phase load 3 is connected to the connecting lines 2a and 2b from the distribution line 1 of the three-phase electric line consisting of the C phase to the two phases of the A-phase electric line and the B-phase electric line, respectively, to form the power feeding line 2. This connection line (separation line) 2b is cut off and connected to a connection line (new line) 2c that connects to an unconnected C-phase electric circuit, and the power supply line B
A case where the phase electric path is switched to the C-phase electric path will be described.

As shown in FIG. 1, a normally-closed switch 5 and a fuse 6 are connected in series to a line switching device 4 of this embodiment, and both ends of the bypass line 7 are connectable to a disconnection line 2b. Is provided. The fuse 6 is composed of a current limiting fuse having an excellent breaking ability in large and small current regions and is replaceable. A branch line 8 is provided via a short-circuit switch 9 so that it can be connected between the C-phase electric circuit and the single-phase load 3.

In this embodiment having such a configuration, the operation of switching the line from the B-phase electric line to the C-phase electric line under the hot line will be described. First, the bypass line 7 is disconnected at the connection points 7a and 7b. Are connected in parallel to form a parallel circuit. Then, the separating line 2b is cut at a cutting point X between the two connection points 7a and 7b. As a result, the feeding line 2 is formed by the bypass line 7. Subsequently, the branch line 8 with the short-circuit switch 9 in the open state is connected to the connection point 8a between the unconnected C-phase connection point 8a and the single-phase load 3 to bring the state of FIG.

Next, as shown in FIG.
Is turned on to connect the branch line 8 and the bypass line 7.
As a result, in the system path, the B-phase electric path and the C-phase electric path are short-circuited, the fuse 6 is melted, and the connection with the B-phase electric path is cut off. It should be noted that the time for interrupting the fault current by blowing the fuse 6 is about 0.5 to 2 cycles of the commercial frequency, and there is no fear that the fault will spread to the power feeding circuit 2. As a result, the power feeding circuit 2 is connected to the A-phase electric circuit and the branch line 8 (new line 2
Switching is performed by the C-phase electric circuit according to c), and power feeding is continued.

In this embodiment, since the bypass line 7 is provided with the normally closed switch 5, the normally closed switch 5 is opened to stabilize the disconnection state to the B-phase electric circuit, and the blown fuse 6 re-points. Both contacts 7a, 7 so that they do not arc
Make sure to open between b. Further, the disconnection line 2b, the bypass line 7, and the short-circuit switch 9 of the branch line 8 are not necessary after the switching, but these can be removed at the time of other power outage work such as planned power outage of the three-phase distribution line.

[Brief description of drawings]

FIG. 1 is a power supply circuit diagram during switching work.

FIG. 2 is a power supply circuit diagram when a short-circuit switch is turned on.

FIG. 3 is a power supply circuit diagram before switching.

[Explanation of symbols]

 1 ... Distribution line 2 ... Feeding line 2a ... Connection line 2b ... Connection line (disconnection line) 2c ... Connection line (new line) 3 ... Single-phase load 4 ... Line switching device 6 ... Fuse 7 ... Bypass line 8 ... Branch line 9 … Short-circuit switch X… break point

Claims (1)

[Claims] 1. A power supply circuit switching device for switching and connecting one connection line of a single-phase two-wire power supply line connecting a single-phase load to two phases of a three-phase distribution line to another one phase, A bypass line connecting a fuse in parallel to a connection line to be disconnected, and a branch line provided with a short-circuit switch in an open state between an unconnected one-phase load and a single-phase load. Power supply line switching device for phase distribution lines.