JPS6053522B2 - Fault position detection device for opening/closing equipment - Google Patents

Description

[Detailed Description of the Invention] This invention incorporates a central conductor that conducts high voltage current;
The present invention also relates to a failure position detection device for switching equipment that detects an internal short-circuit accident in a grounded metal container type power switching equipment sealed with an insulating medium.

A grounded metal enclosure power switchgear includes a switching part that switches the current flow from the high voltage power supply to the load, a central conductor that conducts current between the high voltage power supply and the switching part and between the switching part and the load; Furthermore, it contains an insulating medium such as SF6 gas inside, and is equipped with a grounded metal container made up of a plurality of grounded metal cylinders connected to each other, which surrounds the center conductor and electrically isolates it from the outside air. The grounded metal container is installed in the air at a high point above the ground surface by means of a steel foundation.

A fuse device is provided on the power supply side to prevent current flow if a large current occurs due to an internal short circuit. In conventional switchgear of this type, in the event of an internal short-circuit accident, especially when a large current occurs due to an electric arc between the center conductor and the grounded metal container, the center conductor is completely covered by the grounded metal container. Because it was surrounded, it was not possible to determine the location of the damage caused by the electric arc from the outside.

Therefore, each of the multiple metal cylindrical bodies must be dismantled one by one to inspect the inside, and it takes a considerable amount of time to dismantle the switchgear and inspect the inside, which may disrupt the power supply. There were some shortcomings such as damage. As a conventional device that improves the above-mentioned drawbacks, a resistive impedance is inserted between each of the plurality of metal cylinders connected so that there is no direct electrical continuity with each other and the ground, and the metal Each of the cylindrical bodies was electrically floated from the ground potential, and the potential between both terminals of each resistive impedance was constantly monitored using a monitoring Vcl.

In this conventional device, since the potential of the metal cylinder increases only at the location where an internal short circuit occurs, the monitoring device detects and stores this potential, and displays the location where the electric arc occurs. The role of this monitoring device is to memorize the location of an internal short circuit even after the fuse device is activated and the supply of electricity from the power source is stopped. however,
This conventional device also had the following drawbacks.

In other words, an insulator will be inserted between each metal cylinder and the installation foundation steel, but the weight of the metal container consisting of multiple metal cylinders is extremely large, and the tightening force will be insufficient. is extremely large, so the long-term mechanical strength of the insulator is not sufficient.Furthermore, in the case of outdoor installation, it is exposed to moisture, ultraviolet rays, etc. for a long period of time, so the insulator does not have sufficient electrical and mechanical strength. It has been difficult to maintain the strength, and it has been difficult to detect internal short circuit accidents in such equipment with high reliability. The present invention includes a plurality of detection electrodes disposed at equal intervals along the current direction of the center conductor and arranged to have impedance, particularly capacitive reactance, between each of the center conductor and the grounded metal container. The present invention provides a fault location detection device for switching equipment that is capable of detecting the location of an internal short-circuit accident by constantly monitoring the potential of its electrodes with a monitoring device.

An embodiment of the present invention will be described below based on the drawings.

FIG. 1 is a sectional view showing an embodiment of the present invention, in which 1 is a center conductor through which a high voltage current is passed, 2'' is a grounded metal container surrounding the center conductor 1 electrically isolated from the outside air, and 2 is a grounded metal container that surrounds the center conductor 1 electrically isolated from the outside air. A plurality of grounded metal cylinders constitute a grounded metal container; 3 is an insulating medium such as SF6 gas contained inside the grounded metal container 2''; 4 is an insulating medium such as SF6 gas; A support insulator 5 for supporting the core conductor 1 approximately at the center of the grounded metal container 2'' is arranged so as to have a capacitive reactance between it and the center conductor 1 and with the grounded metal container 2''. 6 is a donut-shaped insulating plate that insulates between each metal cylinder 2 and the detection electrode 5; 1 is a monitoring device incorporating a voltage measuring device (voltmeter) 8 to be described later; 8 is a donut-shaped detection electrode; A voltage measuring device 9 indicating the potential of the detection electrode 5 is grounded.

The detection electrodes 5 are installed at the connecting part of the metal cylinder 2 and insulated from the metal cylinder 2 by a donut-shaped insulating plate 6, and a plurality of detection electrodes 5 are arranged at equal intervals along the current direction of the central conductor 1. . FIG. 2 is a diagram illustrating the operation of the fault position detection device of the present invention configured as shown in FIG.
1 is a power supply that simulates the voltage applied between the center conductor 1 and the cylindrical metal container 2; 12 is a power source that simulates the voltage applied between the center conductor 1 and the cylindrical metal container 2; A switch 13 simulates a short-circuited state; 13 is a capacitive reactance caused by an insulator 4 between the center conductor 1 and the detection electrode 5;
14 is the capacitive reactance due to the insulating plate 6 between the container 2 and the detection electrode 5, 15 is the stray capacitance due to the insulating medium 3 between the center conductor 1 and the container 2, and 1'' is the capacitive reactance between the center conductor 1 and the capacitive reactance 13. 5'' is a point on the circuit representing the connection point between capacitive reactance 13 and capacitive reactance 14.

Next, the operation of the grounded metal container of the present invention constructed as described above will be explained with reference to FIG.

First, when the device of the present invention is operated normally, the switch 12 is in an open state in FIG. 2, and the voltage from the power source 11 is applied in series to the capacitive reactances 13 and 14. Therefore, the capacitive reactance 1
A voltage obtained by dividing the voltage of the power supply 11 by reactances 13 and 14 is applied to 4, and the voltage can be detected by a voltage measuring device 8 connected in parallel to reactance 14. Next, if an internal short-circuit accident occurs in the device of this invention, the switch 12 is in the closed state in FIG. 2, and the center conductor 1
Since the potential of point 1'' on the circuit representing the connection point between capacitive reactance 13 and capacitive reactance 13 is equal to the potential of ground 9, The potential is also ground potential. Therefore, the potential difference across the capacitor 1', that is, the voltage measuring device 8
The instruction will be 0. In this way, the presence or absence of an internal short-circuit accident in the switchgear having the grounded metal container can be determined by whether the detection electrode 5 shows a constant voltage value other than O or shows 0. Further, as shown in FIG. 1, the detection electrodes 5 are arranged at regular intervals in the axial direction of the central conductor 1, and the potential of each of them is constantly monitored by a monitoring device 7.

When an internal short-circuit accident occurs, a large current much larger than the previous load current flows through the center conductor 1, and the center conductor 1 has a large inductive reactance at the beginning of the flow. Therefore, at the moment when an accident occurs, the potential of the central conductor 1 near the location of the accident becomes almost 0, and at the same time, the potential of the detection electrode 5 also becomes O.
As the distance from the accident location increases, the time for the potential to drop to zero potential becomes slower due to the above-mentioned inductive reactance. The monitoring device 7 is used to memorize the chronological order in which each detection electrode 5 becomes 0 potential after an accident occurs until the fuse device is activated, and thereby determines the location where an internal short circuit accident has occurred. It is designed so that you can As mentioned above, the center conductor supporting insulators are usually arranged at appropriate intervals in the axial direction of the center conductor, so the first
As shown in the figure, it is possible to detect the location of an internal short circuit by installing a detection electrode insulated from both the center conductor and the grounded metal container, detecting its potential, and managing it with a monitoring device. . In the fault position detection device in the above-mentioned embodiment, it is sufficient to provide a detection electrode insulated from both the center conductor and the grounded metal container as a detection electrode at the time of a fault, and the detection electrode in other embodiments is as follows. I can think of things.

In Figure 1, a donut-shaped metal plate was used, but this was used in Figure 3.
If the detection electrode 16 is shaped so as to surround the end of the metal cylindrical body 2 as shown in the figure, it can also serve as electric field relaxation.

FIG. 4 shows still another embodiment, in which the detection electrode 17
The voltage applied to the center conductor 1 is divided by the stray capacitances between the and the center conductor 1 and between the detection electrode 17 and the grounded metal container 2'', and by detecting this voltage, an internal short circuit accident is detected. It is something to do.

In addition to the detection electrode shown in FIG. 4 when using the stray capacitance of an insulating medium, a depression may be provided in a grounded metal container and an insulated detection electrode may be placed in the depression.

Typically, such devices have a recess in the grounded metal container that houses the desiccant to maintain the dielectric strength of the insulating medium, so it is also possible to attach the detection electrode to the case that houses the desiccant. It is. For example, if the desiccant is housed in a case made of a well-ventilated wire mesh or the like, and the case is insulated from and attached to a grounded metal container, the wire mesh case can be used as a detection electrode. As described above, the failure location detection device for switching equipment according to the present invention can detect the location of an internal short circuit accident while keeping the grounded metal container grounded without providing insulation between the grounded metal container and the installed foundation steel. Therefore, it has the effect of realizing highly reliable failure location detection over a long period of time.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the detection device of the present invention;
FIG. 2 is an explanatory diagram for explaining the operation of the apparatus of the present invention, and FIGS. 3 and 4 are sectional views showing other embodiments of the present invention.

Claims (1)

[Claims] 1 Constructed by connecting a central conductor connected to the opening/closing part to conduct high voltage current, and a plurality of individually grounded metal cylinders, and surrounding the central conductor while electrically isolating it from the outside. and a grounded metal container containing an insulating medium therein, the switchgear is arranged at intervals along the energizing direction of the center conductor, and each case is located between the center conductor and between the plurality of metal tubes. A plurality of detection electrodes are arranged so as to have capacitive reactance between one of the bodies, and the potential of the plurality of detection electrodes is constantly monitored, and the ground potential of each detection electrode is determined in the event of an internal short circuit accident. A failure position detection device for switching equipment, which is equipped with a monitoring device configured to memorize the order of descent to the terminal, and is configured to detect the location where an internal short circuit accident occurs.