JP2773763B2 - High-voltage three-phase distribution line phase switching device - Google Patents

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 used for switching a phase connected to a single-phase load to a remaining phase in a high-voltage three-phase distribution line having a large three-phase load current imbalance. ).

[0002]

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

In such a case, it is conceivable to reduce the unbalance of the three-phase load current by switching the phase to which the single-phase load is connected to the remaining phase. However, this requires long-term blackout work,
Usually, they were operated without switching the phases.

In view of the above circumstances, the present inventors have invented a phase switching device capable of performing phase switching substantially without power interruption, and have already applied for a patent as Japanese Patent Application No. 4-228772. In the phase switching device of the prior application, as shown in FIG. 7, the first switch 1 is attached in parallel with a cutting point X of a phase b where a distribution line is cut, and a point closer to a load L than the cutting point X is connected. A non-contact switch 3 that performs a high-speed closing operation following the opening of the first switch 1 is attached between the connected phase c and the closing operation following the closing operation in parallel with the non-contact switch 3. And a second switch 2 for performing the above operation.

In this phase switching device, the first switch 1 is turned on to cut off the cutting point X, and at the same time, the first switch 1 is turned off, and at the same time, the non-contact switch 3 is turned on to instantaneously switch phases. Further, the construction is performed in such a manner that the second switch 2 is closed and then the second switch 2 is connected in parallel. However, in the phase switching device of the prior application, for example, when the non-contact switch is turned on even though the first switch is not opened, there is a possibility that an inter-phase short-circuit accident may occur.

[0006]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems in the prior art, and enables high-voltage three-phase distribution in which phase switching can be carried out without interruption and completely preventing the possibility of a short circuit accident or the like. It has been completed to provide a phase switching device for electric wires.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a first switch mounted in parallel with a cutting point of a phase where a distribution line is cut, and a load which is higher than the cutting point. A non-contact switch that performs a high-speed closing operation following the opening of the first switch between the side point and the connected phase, and further closes the closing operation in parallel with the non-contact switching unit. In the phase switching device equipped with the second switch to be performed, a current detecting means is provided in each switch, and a control device is provided which detects a current and switches a phase each time each switch operates. It is characterized by the following.

[0008]

In the phase switching device for high-voltage three-phase distribution lines according to the present invention, the control device advances the phase switching while confirming the operation of each switch by the current detecting means attached to each switch. Can be completed while the phase switching is completed. The specific configuration and procedure will be described in detail with reference to the following examples.

[0009]

[Embodiment 1] FIG. 1 is a circuit diagram showing a configuration of a first embodiment, in which a load L connected between a and b of a three-phase distribution line a, b and c is connected to a-a. An example is shown in which switching is made between c. Where b is the phase to be disconnected, c is the phase to be connected,
Let X be the cutting point. 1 is a cutting point X of the phase b to be cut.
Contact type first switch (SW
) 3 is a non-contact switch (SCR) provided between the point on the load L side of the disconnection point X and the connected phase b and performs a high-speed closing operation following the opening of the first switch 1. is there. As the non-contact switch 3, a semiconductor switch using a semiconductor such as a thyristor is used, for example. A second switch (SW) 2 is mounted in parallel with the contactless switch 3 and performs a closing operation following the closing operation of the contactless switch 3.
It is.

In the present invention, current detecting means 4 (CT) such as CT, 5 (CT), and 6 (CT) are provided on the power supply side of the first switch 1, the second switch 2, and the contactless switch 3. C
T) is attached so that the operation of each switch can be checked. Outputs of these current detecting means 4, 5, and 6 are input to the control device 7. The control device 7 is connected to each of the first switch 1, the second switch 2, and the contactless switch 3, and can control the opening and closing operations of these switches.

Next, the operation of the apparatus shown in FIG. 1 will be described with reference to FIG. First, each device is connected to the cable of the three-phase distribution line as shown in FIG. 1, and the first switch 1 (SW) is turned on. At this time, the control device 7 confirms that a current is flowing to the current detecting means 4 (CT), and if no current is flowing, issues an abnormal alarm and stops the operation. When it is confirmed that a current is flowing through the current detecting means 4 (CT), the control device 7 issues an instruction to cut the electric wire and cuts the phase b to be cut from the cutting point X.

Next, the first switch 1 (SW) is turned off,
Subsequently, the control device 7 switches the contactless switch 3 (SCR).
Is turned on at high speed, but in the present invention, the first switch 1 (SW
) Is turned off, the control device 7 confirms that no current is flowing through the current detecting means 4 (CT). If a current flows through the current detecting means 4 (CT) even though the first switch 1 (SW) is turned off, there is an abnormality such as the first switch 1 (SW) is not turned off. Therefore, an abnormal alarm is immediately issued and the operation is stopped.

If it is confirmed that the operation is normal, the control device 7 turns on the non-contact switch 3 (SCR) at a high speed and confirms that a current is flowing through the current detecting means 6 (CT). . Turning on the non-contact switch 3 (SCR) means that the phase can be switched. However, in order to prevent a long-time current from flowing through the non-contact switch 3 (SCR), the control device 7 continues to operate. The second switch (SW) is closed. For this reason, even when the current detection means 6 (CT) does not detect a current even though the non-contact switch 3 (SCR) is turned on, the second switch (SW) is closed only by issuing an alarm.

After confirming that a current is flowing through the current detecting means 5 (CT), the electric wire is connected as shown by a broken line. However, if no current is flowing through the current detection means 5 (CT), the second switch (SW) is not turned on, so that an abnormal alarm is issued and the operation is stopped. When the connection of the electric wires is completed in this way, the non-contact switch 3 (SCR) and the second switch (SW) are turned off, and each device is removed, and all operations are completed.

FIG. 3 shows a time chart of the operation of each switch at the moment of phase switching. The time indicated by T in this time chart is the power outage time, but the length is only about half a cycle of the commercial frequency, so that the phase switching work can be performed almost without power outage.

[Embodiment 2] FIG. 4 is a circuit diagram showing a configuration of a second embodiment, and a first switch (SW) shown in FIG.
Only the point that a non-contact switch 8 (SCR) is attached in parallel with the first embodiment differs from the first embodiment. FIG. 5 is a flowchart showing the operation of the second embodiment. In the first embodiment, the first switch (SW) is turned off, and the current detecting means 4 (CT
), It is confirmed that no current flows, and subsequently, the non-contact switch 3 (SCR) is turned on at a high speed. On the other hand, in the second embodiment, the non-contact switch 8 (SCR) is turned on before the first switch (SW) is turned off. Then, the non-contact switch 8 (SCR) is turned off, and after confirming that no current flows through the current detecting means 4 (CT), the non-contact switch 3 (SCR) is turned on at a high speed. If the current is flowing through the current detecting means 4 (CT) even though the non-contact switch 8 (SCR) is turned off, the non-contact switch 8 (SCR) is not turned off. After the first switch (SW) is turned on to prevent a short circuit accident, an alarm is issued and the operation is stopped. Other parts are the same as those in FIG. In addition,
FIG. 6 is a time chart showing the operation of the second embodiment, and it can be seen that the blackout time t has become shorter due to the attachment of the non-contact switch 8 (SCR).

[0017]

As described above, the phase switching device for a high-voltage three-phase distribution line according to the present invention can perform phase switching substantially without interruption, and furthermore, each switch is provided with current detecting means. Thus, each time each switch operates, current is detected and phase switching is performed, so that the possibility of a short circuit accident or the like can be completely prevented. Therefore, the present invention greatly contributes to industrial development as a phase switching device for a high-voltage three-phase distribution line that solves the conventional problems.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a configuration of a first embodiment.

FIG. 2 is a flowchart illustrating the operation of the apparatus according to the first embodiment.

FIG. 3 is a time chart of a phase switching operation in the device of the first embodiment.

FIG. 4 is a circuit diagram showing a configuration of a second embodiment.

FIG. 5 is a flowchart illustrating the operation of the device according to the second embodiment.

FIG. 6 is a time chart of a phase switching operation in the device of the second embodiment.

FIG. 7 is a circuit diagram showing a configuration of a phase switching device of the prior application.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st switch (SW) 2 2nd switch (SW) 3 Non-contact switch (SCR) 4 Current detecting means (CT) 5 Current detecting means (CT) 6 Current detecting means (CT) 7 Control device 8 None Contact switch (SCR)

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H02J 3/00-5/00

Claims (2)

(57) [Claims] 1. A first switch is mounted in parallel with a cut point of a phase of a distribution line to be cut, and the first switch is opened between a phase connected to a point on the load side of the cut point. In a phase switching device in which a non-contact switch that performs a closing operation at high speed is mounted subsequently, and a second switch that performs a closing operation following the closing operation is mounted in parallel with the non-contact switch, current is supplied to each of the switches. A phase switching device for a high-voltage three-phase distribution line, comprising: a detection device; and a control device that detects a current and switches a phase each time each switch operates. 2. The high-voltage three-phase distribution line phase switching device according to claim 1, wherein a non-contact switch is mounted in parallel with the first switch.