JPH0442634B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for performing a withstand voltage test by applying a test voltage from the outside to an internal circuit of a gas insulated switchgear.

All general electrical equipment, not just gas-insulated equipment, is required to undergo a withstand voltage test based on electrical equipment technical standards after being installed on-site. Air-insulated electrical equipment, which is commonly used in this withstanding voltage test, does not cause any problems in applying the test voltage because the voltage application point is in the air, but the situation is completely different with gas-insulated equipment. That is, in the case of a gas-insulated switchgear, all of the live parts are housed in a grounded container, and there is no risk of the live parts coming into direct contact with the human body.

However, even if you try to apply a test voltage on-site, the application point is not exposed to the air, so testing cannot be performed in the same way as with air-insulated electrical equipment.

Therefore, conventionally, voltage application points for on-site testing are generally provided in advance when manufacturing equipment.

FIG. 1 shows an example in which a voltage application point is provided on the connection side of a gas insulated switchgear to a transformer. To explain the figure, the gas insulated switchgear 1 has a connection case 3 filled with insulating gas on the side connected to the transformer, and a bushing pocket 4 of the transformer is connected to the bottom surface of the case 3 via a partition plate 5. Oil-gas bushings 6 for three phases of the transformer are installed through the partition plate 5. The bushing 6 of each phase has a connecting conductor 7 attached vertically to the gas side terminal, and a conductor 2 extending from the switchgear 1 is connected to this connecting conductor 7. Test terminals 7a are provided at the upper end and are formed to have the same height. 8 is a test bushing that is attached to the upper part of the connection case 3 after on-site installation via an adapter 9, and the contact plate 10 attached to the lower terminal of this bushing 8 contacts the test terminals 7a for the three phases,
By applying a test voltage through the bushing 8 during a withstand voltage test, the withstand voltage test of the internal circuit can be performed for three phases at once.

However, since the above-mentioned device has a configuration in which the test bushing 8 is attached during the withstand voltage test, a part of the internal space of the switchgear is exposed to the atmosphere when the bushing is attached or disassembled.
It is necessary to refill the insulating gas each time. This requires a lot of effort and work time, and it is also necessary to prepare a space in advance for air insulation in the switchgear in order to install the test bushings, which limits the configuration of the equipment. There were other problems.

The purpose of the present invention is to make it possible to apply a test voltage from the outside while maintaining the gas-tightness of the switchgear without any complicated work during a withstand voltage test.
Another object of the present invention is to provide a withstand voltage testing device for a gas insulated switchgear that can be easily switched to an operating state after the test.

An embodiment of the present invention will be described below with reference to the drawings. In FIGS. 2 and 3, 1 is a gas insulated switchgear, 2 is a current-carrying conductor of the device, 3 is a connection case,
4 is a bushing pocket for the transformer, 5 is a partition plate,
6 is an oil-gas bushing of the transformer, 7 is a connecting conductor, and 7a is a test terminal, and each of the above parts corresponds to the parts shown with the same symbols in FIG. 11 is an upper cover of the connection case 3, and 12 is a cable connecting device that is attached to the upper cover 11 and is detachable from the test cable 21 that is inserted from the outside. As shown in FIGS. 4 and 5, the cable connection device 12 includes a rod 14 that is movable in an airtight state and is installed in an insulating tube 13 that is gas-tightly attached to the back surface of the opening 11a of the cover 11. A contact 15 is attached to one end of 14.
A plug-in type connecting portion (connector) shown in FIGS. 4 and 5 is attached thereto, and a dish-shaped contact plate 16 is supported at the other end. When the test cable 21 is inserted from the outside, the rod 14 automatically connects to the test cable conductor as the cable terminal 22 via the contact 15 at a predetermined lowered position as shown in FIG. is in pressure contact with the test terminal 7a for three phases. The internal circuit provided with this terminal 7a is connected to an external test power source. When the test cable 21 is in the inserted state, the opening 11a of the cover 11 is closed by the cable sheath 23. In addition, the cable end portion inside the outer sheath 23 is connected to the spring 24.
Insulation is ensured by pressurizing the insulating collar 25 to the inner surface of the insulating cylinder 13.

On the other hand, after the cable 21 is pulled out after the withstanding voltage test, the rod 14 is pulled up to a predetermined raised position by the stud 26 attached to the screw hole at its end from above, and inserted into the insulating tube 12 in advance, as shown in FIG. It is supported in that position by the insulating stand 27 that has been installed through the spring 28, and is grounded to the same potential as the cover 11 via a grounding member (not shown) inside the cap 29 attached to the opening 11a. The contact plate 16 is separated from the test terminal 7a by the movement of the rod 14 to the raised position, and is held at a position where a predetermined insulation distance is maintained.

According to the above configuration, during a withstand voltage test, the internal space of the switchgear can be opened to the atmosphere by inserting the test cable 21 from the outside into the cable connection device 12 provided in the gas-insulated switchgear 1. Since it can be automatically connected to the test terminals 7a for three phases of the internal circuit through the rod 14 and contact plate 16 of this device 12 while maintaining this gas-tight state, there is no need to perform gas refilling process, etc. as in the conventional case. Withstand voltage tests can be performed very easily and quickly without the need for any additional work. Further, even after the test cable 21 is pulled out after the withstand voltage test, the rod 14 is pulled up to a predetermined position and grounded without opening the switchgear to the atmosphere, so that the contact plate 16 also becomes the ground potential and the test terminal 7a Since it opens at a position where a predetermined insulation distance is maintained between the two and the same, there is no problem with steady operation and the operating state can be quickly switched to. Furthermore, since one cable connection device 12 common to the three phases is used as the test voltage application point, it can be installed in a small space and there is no need to provide a special air insulation space at the installation part. Therefore, there are no restrictions on the structure of the switching device 1, and the entire device can be downsized.

As described above, according to the present invention, it is possible to easily apply a test voltage from the outside without any disassembly work, and it is possible to quickly switch to the operating state after the test. We can provide withstand voltage testing equipment for insulated switchgear.

In addition, since the cable connection device facing the test terminal for three phases is common for all three phases, it is possible to use one cable connection device as a test voltage application point to test all three phases at the same time. Since there is no need to provide a cable connection device for each installation, installation space can be saved and installation can be done in a small amount of space. It can be made smaller and more compact.

Furthermore, since the rod has a contact plate at one end and a plug-in connection at the other end, it is possible to reliably and stably connect the test cable conductor and the rod when inserting the test cable. .

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional withstand voltage test device for gas insulated switchgear, and FIGS. 2 and 3 are test and non-test conditions of the withstand voltage test device for gas insulated switchgear according to an embodiment of the present invention. Sectional view showing the state, No. 4
5 and 5 are detailed cross-sectional views showing the cable connection device of the same device in a voltage proof test state and a non-test state. DESCRIPTION OF SYMBOLS 1... Gas insulated switchgear, 3... Case, 7a... Test terminal, 12... Cable connection device, 14... Rod, 16... Contact plate, 21... Test cable.

Claims (1)

[Claims] 1 A test terminal for three phases formed in a part of the inter-case electrical circuit of a gas-insulated switchgear, and a cable connection device common to the three phases facing the tip of this test terminal, and the above cable connection device The insulating cylinder is gas-tightly attached to the opening of the case, the rod is movably provided in the insulating cylinder in an airtight state, the contact plate is fixed to one end of the rod, and the rod is connected to the insulating cylinder in a gas-tight manner. a plug-in type connection provided at the other end of the rod, the rod having a predetermined lowered position where the plug-in type connection connects to a test cable conductor inserted from the outside into the insulating tube; When the test cable is removed, it is pulled up to a predetermined raised position, and in the lowered position of the rod, the contact plate contacts each of the test terminals for three phases, and in the raised position, the contact plate is opened from the test terminal. A withstand voltage test device for gas insulated switchgear, characterized in that it is separated.