JPH0678461A - Switching device of phase of high-tension three-phase distribution line - Google Patents

Abstract

PURPOSE:To furnish a switching device of a phase of a high-tension three-phase distribution line which can switch over the phase connected with a single-phase load, without power stoppage substantially. CONSTITUTION:A contactless switch 1 or a contact-provided switch 2 is fitted in parallel with a disconnection point of a phase (b) to be disconnected, and a contactless switch 3 is fitted between a point located nearer onto the load side than the disconnection point of the phase (b) to be disconnected and a phase (c) to be connected. By giving an opening instruction to the switch 1 or 2 to open it and also by closing the contactless switch 3 at a high speed in succession to the opening of the switch l or 2, switchover of the phase is completed in a moment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-voltage three-phase distribution line phase switching device used for switching the phase to which a single-phase load is connected in a high-voltage three-phase distribution line having a large three-phase load current imbalance. It is about.

[0002]

2. Description of the Related Art A single-phase load is connected to a high-voltage three-phase distribution line for any two phases out of the three phases, but in an actual system, the single-phase load is concentrated on a specific two phases. Often connected. In such a case, an unbalanced state of the three-phase load current is caused, the utilization efficiency of the electric power equipment is deteriorated, and the load of the three-phase induction motor is also affected.

Therefore, in such a case, it is conceivable to reduce the imbalance of the three-phase load current by switching the phase to which a part of the single-phase loads are connected. However, this requires construction that involves a long power outage, so it was usually operated without switching phases.

[0004]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and is capable of switching the phase to which a single-phase load is connected, without interruption, of a high-voltage three-phase distribution line. It was made to provide.

[0005]

DISCLOSURE OF THE INVENTION The present invention made to solve the above problems is to install a switch in parallel with a cutting point of a phase to be cut of a high-voltage three-phase distribution line and to cut the phase to be cut. Between the point on the load side of the point and the connected phase, a non-contact switch which performs a closing operation at a high speed following the open circuit of the switch is attached. As the switch to be attached to the phase to be disconnected, one or both of a contact switch and a non-contact switch can be used as shown in the examples below.

[0006]

In order to perform the phase switching work using the phase switching device of the present invention, first, the switch installed in parallel with the disconnection point of the phase to be disconnected of the high voltage three-phase distribution line is closed and then the disconnection point is cut. . Next, give an open command to this switch,
If a contactless switch mounted between the point on the load side of the disconnection point of the phase to be disconnected and the connected phase is closed at a high speed following the opening of the switch, the phases can be switched instantaneously. Be seen. In this case, the power failure time is a very short time from the opening of the switch of the phase to be disconnected to the closing of the contactless switch, and there is an advantage that the work can be performed by the instantaneous power failure of about half cycle to several cycles. Hereinafter, the present invention will be described in more detail with reference to the illustrated embodiments.

[0007]

Example 1 This example shows an example in which a contact switch and a non-contact switch are used together as a switch attached to a phase to be disconnected, and the construction procedure is shown in FIGS. 1 to 6. Will be explained later.
Here, as shown in Fig. 1, a, b, and
Single-phase load L connected between a and b of the three phases of c
Are to be switched so that they are connected between a and c as shown in FIG. In this case, c
In order to connect the phases, the b phase is called a disconnected phase and the c phase is called a connected phase.

First, as shown in FIG. 2, the phase b to be cut is
The contactless switch 1 and the contact switch 2 are installed in parallel with the cutting (planned) point. As the contactless switch 1, for example, a switch using a thyristor element can be used. The contactless switch 1 and the contact switch 2 are in an open state when mounted. Further, the contactless switch 3 and the contact switch 4 in the open state are also installed in parallel between the phase c connected to the point on the load side of the disconnection point of the phase b to be disconnected. This completes the phase switching device of the high-voltage three-phase distribution line of the present invention.

The contact switch 2 of the phase b to be cut next is closed, and the main line of the phase b is cut at the cutting point. Then, the contactless switch 1 is closed. FIG. 2 shows this state. Next, when the contact switch 2 is opened, the current of the phase b to be disconnected flows through the contactless switch 1. FIG. 3 shows this state. Next, the open command is given to the contactless switch 1 to stop the power transmission from the phase b to the load L, and the contactless switch 3 is closed at a high speed following the opening of the contactless switch 1. During this period, the load L is in a power failure state for a few ms, but since it is an instantaneous power failure that is shorter than one cycle, it has almost no effect. FIG. 4 shows this state.

Following the closing of the contactless switch 3, the contact switch 4 is closed. Then, when the contactless switch 3 is opened after the closed circuit of the contact switch 4, the current of the connected phase c flows to the load L through the contact switch 4. FIG. 5 shows this state. Finally, as shown by the alternate long and short dash line in FIG. 5, phase b and phase c are arranged in parallel with the contact switchgear 4.
The phase switching is completed when all the switches are removed after connecting between and. This state is shown in FIG.

As described above, according to the first embodiment, since the contactless switch 3 is closed after the open circuit of the contactless switch 1, the phases can be switched by an instantaneous power failure shorter than one cycle. Further, since the contact switches 2 and 4 are provided in parallel with the respective contact switches 1 and 3, the contact switches 1 and 3 are not provided.
There is an advantage that the contactless switches 1 and 3 can be downsized because the time for passing the current through the device is short.

Embodiment 2 This embodiment shows an example in which only the contact switch 2 is used as the switch attached to the phase to be disconnected.
~ Figure 10 shows the construction procedure. Since this procedure corresponds to FIGS. 2 to 5 of the first embodiment, repeated description of the same parts will be omitted. In this example,
The open command is given to the contact switch 2 from the state of FIG. 8, and the contactless switch 3 is closed at a high speed following the opening of the contact switch 2, but the operation of the contact switch 2 is the same as in the first embodiment. Since the contactless switch 1 is slightly slower, the power failure time is slightly longer. However, since the contactless switch 1 of the first embodiment can be omitted, there is an advantage that the device is simple.

Embodiment 3 This embodiment shows an example in which the contact switches 2 and 4 of Embodiment 1 are omitted, and the construction procedure is shown in FIGS. 11 to 14.
In this embodiment, the contactless switch 1 is opened from the state shown in FIG.
Since the contactless switch 3 is instantaneously closed after the open circuit, phase switching can be performed in a very short power failure time as in the first embodiment. However, since the contact switches 2 and 4 are omitted, the current is supplied to the contactless switch 1 for a relatively long time.
Therefore, it is necessary to increase the size of the non-contact switches 1 and 3 and enhance the cooling function.

[0014]

As described above, according to the present invention, the switching of the phase to which the single-phase load is connected can be performed substantially without interruption, so that the unbalanced state of the three-phase load current can be eliminated. It can be easily resolved. Therefore, the present invention has an extremely great contribution to industrial development as a phase switching device for a high-voltage three-phase distribution line that solves the conventional problems.

[Brief description of drawings]

FIG. 1 to FIG. 6 show a construction procedure of a first embodiment, and FIG. 1 is a circuit diagram showing a state before construction start.

FIG. 2 is a circuit diagram showing a state in which a switch is attached to phase b and interphase bc.

FIG. 3 is a circuit diagram showing a state in which the main line of phase b is cut off.

FIG. 4 is a circuit diagram showing a state in which a switch for phase b is opened and a switch for interphase b-c is closed.

FIG. 5 is a circuit diagram showing a state of connecting between phase b and phase c.

FIG. 6 is a circuit diagram showing a construction completion state.

FIG. 7 to FIG. 10 show a construction procedure of the second embodiment,
FIG. 7 is a circuit diagram showing a state in which a switch is attached to the phase b and the interphase bc.

FIG. 8 is a circuit diagram showing a state in which the main line of phase b is cut off.

FIG. 9 is a circuit diagram showing a state in which a switch for phase b is opened and a switch for interphase b-c is closed.

FIG. 10 is a circuit diagram showing a state of connecting between phase b and phase c.

11 to 14 show a construction procedure of the third embodiment, and FIG. 11 is a circuit diagram showing a state in which a switch is attached to the phase b and the interphase bc.

FIG. 12 is a circuit diagram showing a state in which the main line of phase b is cut off.

FIG. 13 is a circuit diagram showing a state in which a switch for phase b is opened and a switch for interphase b-c is closed.

FIG. 14 is a circuit diagram showing a state of connecting between phase b and phase c.

[Explanation of symbols]

 1 Non-contact switch 2 Reed switch 3 Non-contact switch 4 Reed switch b Phase to be disconnected c Phase to be connected

Claims (1)

[Claims] 1. A switch is installed in parallel with a cutting point of a phase to be cut of a high-voltage three-phase distribution line, and a switch is connected between a point on a load side of the cutting point of the phase to be cut and the phase to be connected. A phase switching device for a high-voltage three-phase distribution line, which is equipped with a non-contact switch that closes at high speed following the opening of the switch.