JPH0410028B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an impulse voltage application phase switching device that saves labor and improves work safety during impulse voltage testing of electrical appliances in a factory.

For example, induction electrical equipment such as transformers are subjected to a grounding mine impulse withstand voltage test (hereinafter referred to as an earthing test) and an ungrounded mine impulse withstanding voltage test (hereinafter referred to as an ungrounded test).

In the earthing test, the impulse voltage generator is connected to the application phase terminal connected to the conductor of the phase to which the voltage of the electrical equipment under test is to be applied. The terminals of other phases are directly grounded. After these preparations are completed, first, a full wave voltage having a specified sever voltage peak value is applied to the voltage application terminal through a sever gap set between the terminal under test and the ground, and a sever voltage is applied at the wave tail. Apply a disconnected lightning impulse voltage. Next, a lightning impulse voltage having a specified full-wave voltage peak value is applied as quickly as possible.

For ungrounded tests, connect all phase terminals of the electrical equipment under test to which voltage is applied to an impulse voltage generator, and leave the neutral point open depending on the usage condition.
Alternatively, appropriate measures may be taken, such as attaching a discharge gap or grounding through a suitable resistor.

In addition, to detect the presence or absence of an abnormality in the test, before performing the main test at the specified peak voltage, conduct a preliminary test at a reduced voltage (voltage 50 to 75% of the specified value) using the same connection circuit as the main test. At that time, take pictures of the waveforms of the applied voltage and ground current, compare them with the waveforms during the actual test, and if there is no change, it is assumed that there is no abnormality.

FIG. 1 is a perspective view of a conventional test device of this kind, in which the voltage generated by an impulse voltage generator 1 is passed through a voltage measuring voltage divider 2 to which a severing device 4 equipped with a severing gap 3 is connected. The voltage is sequentially applied to the application phase bushings 6 of the test device 5. 7 is an impulse control room and 8 is a measurement room. When testing with these devices, first select the test phase. Switching the wiring for this purpose requires work at a high place to connect the voltage divider 2 and the top of the bushing 6, so conventionally the work has been done using a gondola 10 suspended from a crane 9. As a result, work efficiency was extremely low and it was also dangerous. In addition, in preparation for the test, the wave breaker 4 and the voltage divider 2 are distributed at appropriate locations, and wires are connected between them. Adjustment of the cutting gap 3 requires a lot of time, not only when the voltage is different, but also when the voltage is the same, because it is necessary to apply a scale to each phase and adjust the gap length or remove the gap each time the test is performed. However, there was a drawback that the testing site could not be used effectively.

FIG. 2 is a flowchart of a conventional lightning impulse test for a three-phase three-winding transformer, and the repetition of the crane operation and the cutting gap adjustment is clear. An example will be shown in which the test begins with the primary side U-phase test after making preparations such as equipment placement and wiring. The first test is a ground test in which a reduced voltage is applied, the cutting gap is adjusted, and a cutting wave is applied. Next, remove the above-mentioned cutting gap or greatly widen the gap length to ensure that there will be no flashover between them, then apply full-wave voltage, and if the failure judgment passes, the applied phase can be transferred to the next phase by crane operation. , and repeat the same tests as above in sequence. Once the above grounding test of the primary winding is completed, use a crane to change the wire connections and move on to the non-grounding test. Therefore, after applying a reduced voltage, a full wave application test is performed, and if the failure judgment is passed, the wiring is changed to the secondary side by crane work, for example.
Repeat the above tests. In other words, for a three-phase converter, each winding (for example, the primary winding) requires at least six cutting gap adjustments and nine crane operations, so it would be a great benefit if these operations could be simplified or omitted. becomes.

This invention eliminates the above-mentioned drawbacks of the prior art and aims to eliminate work at heights, rationalize testing, save labor, and effectively utilize testing sites. This objective was achieved by configuring the impulse voltage application phase switching device of the impulse testing device as follows. That is, in a device that sequentially applies the voltage generated by an impulse voltage generator to the voltage application phase terminals of the device under test via a voltage measuring voltage divider to which a breaker device having a breaker gap is connected, A plurality of insulating cylinders arranged in a straight line and housing a relay terminal connected to the voltage application phase terminal of the power supply via a cable and a grounding mechanism that allows the grounding of the relay terminal to be operated from a distance, the voltage divider and a cart equipped with a severing device and movable in parallel to the direction in which the insulating cylinders are arranged by remote control; and a free end extending from the high-voltage side electrode of the voltage divider to which the slicing device is connected. is configured to include a connection bar that is provided so as to be able to come into contact with the relay terminal.

3 and 4 are a perspective view and a detailed perspective view, respectively, showing the overall relationship of the embodiment of the present invention.
This converts the voltage generated by the impulse voltage generator 1 into the voltage measuring voltage divider 21 and the insulating tubes 22, 23, 24.
This is a device that applies voltage to any one of the bushings 6 of the test device 5 through any one of the relay terminals provided in the test device 5. Further, the voltage divider 21 is provided with a high-voltage side electrode 27a of a severing gap 27 connected to the connecting bar 26, which is connected to the relay terminal 25 of the insulating cylinders 22, 23, and 24. A wave breaking device 29 equipped with a ground side electrode 27b corresponding to the electrode, and an adjustment device 28 capable of moving the electrode to adjust the distance between it and the high voltage side electrode 27a.
is provided.

Relay terminal 25 at the top of insulating cylinders 22, 23, 24
is provided with a reel 31 for winding and storing a cable 30 which has one end connected to the relay terminal and the other end connected to the bushing 6 to which voltage is to be applied. The reel can pull out the other end of the cable 30 out of the insulating tube by applying force, or automatically rewinds the pulled-out cable by reducing the force. Each insulating cylinder 22, 23, 24 has a grounding mechanism 3 that sets the potential of the relay terminal 25 to the ground potential or floats it above the ground potential.
2 is provided. This grounding mechanism connects the cable attached to the relay terminal and the insulated wire, and is capable of winding and unwinding. The insulating tube 2
2, 23, and 24 at intervals, a cart 33 is provided that can move in the direction in which the insulating tubes are lined up, and on which the voltage divider 21 and the wave breaking device 29 are mounted;
The truck may move on a track 34. By this movement, the bushing 6 of the application phase can be connected to the impulse voltage generator via the cable 30 connected to the relay terminal 25 of the insulating tube. To connect the relay terminal 25 and the bushing 6, a hook-shaped fitting at the end of a pull rod is hooked onto, for example, an annular body provided at the end of the cable 30.
The two cables can be tightly stretched between the relay terminal 25 and the bushing 6 by pulling down the tip of the cable and tying it to the tip of a cable pulled down from a reel of a similar structure provided on the bushing 6.

The adjustment device 28, the grounding mechanism 32, and the trolley 33 are provided with an electric motor and a control device (not shown) capable of operating each of them in a predetermined manner, and are operated from a distance.
With this configuration, the cutting gap 2
7 adjustment, voltage application phase switching, and grounding can be performed automatically from a distance.

Also, during the test, the distance between the impulse voltage generator and the voltage divider 21 changes, so the lead wire 36 connecting them needs to be expandable. This can also be easily achieved by providing either the voltage divider 21 or the voltage divider 21.

As is clear from the above explanation, when switching the voltage application phase, the work of grounding the bushing or floating it above the ground potential and applying the test voltage can be done without having to work at high places using a gondola as in the past. This increases work efficiency and also has advantages in terms of safety. The cutting gap can be easily adjusted during testing, and the grounding mechanism and the trolley are equipped with control devices that operate each of them in a predetermined manner, making it even more convenient because they can be operated from a distance.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a conventional impulse voltage testing device, FIG. 2 is a flowchart of a conventional three-phase three-winding transformer lightning impulse voltage test, and FIG. 3 is a perspective view of an impulse voltage testing device according to the present invention. FIG. 4 is a detailed diagram of the impulse voltage application phase switching device section in FIG. 3. DESCRIPTION OF SYMBOLS 1... Impulse voltage generator, 5... Equipment under test (transformer,), 6... Bushing, 21... Voltage measurement voltage divider, 22, 23, 24... Insulating cylinder, 26
... Connection bar, 25 ... Relay terminal, 27 ... Cutting gap, 27a ... High voltage side electrode, 27b ...
Ground side electrode, 28... Adjustment device, 29... Wave breaking device, 30... Cable, 31... Cable reel, 32... Grounding mechanism, 33... Trolley.

Claims (1)

[Claims] 1. A device that sequentially applies the voltage generated by an impulse voltage generator to voltage application phase terminals of a device under test via a voltage measuring voltage divider connected to a severing device having a severing gap. , a plurality of insulating cylinders arranged in a straight line accommodate a relay terminal connected to the voltage application phase terminal of the device under test via a cable and a grounding mechanism that allows the grounding of the relay terminal to be operated from a distance. a cart equipped with the voltage divider and the severing device and movable in parallel to the direction in which the insulating tubes are arranged by remote operation; and a high-voltage side electrode of the voltage divider to which the slicing device is connected. An impulse voltage application phase switching device comprising: a connection bar extending from the terminal and having a free end contactable with the relay terminal. 2. In the device according to claim 1,
An impulse voltage application phase switching device comprising a cable wound around an automatic winding cable reel, one end of which is connected to a relay terminal and the other end of which is connected to a bushing to which voltage is to be applied.