JP5539420B2 - Electrical test apparatus and electrical test method - Google Patents

Description

  The present invention relates to an electrical test apparatus and electrical test method used for testing electrical characteristics of high-voltage equipment.

In general, for parts used in high-voltage electrical equipment such as cable termination connections (bushings, epoxy seats, etc.), in order to confirm safety before use, commercial frequency withstand voltage test, commercial frequency part Various electrical tests such as a discharge test and a lightning impulse withstand voltage test are performed. When such an electrical test is performed in the air, air discharge and surface flashing occur, so the test is performed with the sample placed in an insulating gas atmosphere with high dielectric strength.
In a conventional electrical test apparatus, sulfur hexafluoride (SF ₆ ) is used as an insulating gas (for example, Patent Document 1). Since SF ₆ gas has a dielectric strength superior to that of natural gas such as dry air (oxygen: about 20%, nitrogen: about 80%) and nitrogen (N ₂ ) gas, it is suitable as an insulating gas for electrical tests. .

Japanese Unexamined Patent Publication No. 7-140197 JP-A-3-243105

However, SF ₆ gas has a global warming potential of 23,900 times that of carbon dioxide and is designated as a greenhouse gas subject to emission reduction under the Kyoto Protocol. . In addition, when SF ₆ gas is used for electrical tests, a recovery facility for recovering SF ₆ gas after the test and a separation facility for reusing SF ₆ gas are required, and the test time is extended for recovery and separation. To do.
Therefore, an alternative gas for SF ₆ gas is being sought, but alternative gases (dry air, nitrogen gas, etc.) that are listed as candidates from the viewpoint of environmental adaptability (low global warming potential) and toxicity are SF Dielectric strength is low compared with ₆ gases and is not suitable as an insulating gas for electrical tests.

On the other hand, as a method for efficiently filling an insulating gas into a container, Patent Document 2 describes that bubbles formed by blowing an insulating gas into a liquid insulating medium are filled in the container and then the bubbles are formed. It is disclosed that the liquid insulating medium is discharged. According to the technique described in Patent Document 2, since the bubbles (containing the insulating gas) coming out from the exhaust valve can be visually confirmed, the time when the container is filled with bubbles, that is, the insulating gas, is not delayed. You can know.
However, the technique described in Patent Document 2 is not intended to increase the dielectric strength of the insulating gas by evaporating the insulating component of the insulating solution. In other words, even if the technique described in Patent Document 2 is applied, the insulating gas contained in the foam is mainly filled in the container, so that it is also necessary to use an insulating gas having high dielectric strength such as SF ₆ gas. . Moreover, in patent document 2, after a bubble is charged to the voltage charge part side, a bubble tears after progress for a fixed time, and the air inside a tank exists in a bubble inside by discharging | emitting a liquid insulating medium from a drainage valve. It was replaced with the insulating gas. Therefore, it is necessary to wait for a certain period of time until the bubble sent to the voltage charging unit side is broken, and after that, an operation of discharging excess insulating medium is required before the electrical test.

An object of the present invention is to provide an electrical test apparatus and an electrical test method capable of performing an electrical test without using SF ₆ gas having a high global warming potential and greatly reducing the test time. is there.

An electrical test apparatus according to the present invention includes a container for storing a sample,
A voltage application unit for applying a voltage to the sample contained in the container;
A bubbling gas is introduced into the insulating solution to generate bubbles, and an insulating component dissolved in the insulating solution is vaporized in the bubble to generate a mixed gas composed of the bubbling gas and the vaporized insulating component. And a bubbling portion that fills the container with the mixed gas,
And a gas supply unit for supplying the bubbling gas to the bubbling unit.

The electrical test method according to the present invention includes a first step of placing a sample in a container,
Bubbling gas is introduced into the insulating solution to generate bubbles, the insulating component dissolved in the insulating solution is vaporized in the bubbles, and the mixed gas composed of the bubbling gas and the vaporized insulating component is A second step of filling the container;
And a third step of measuring electrical characteristics by applying a voltage to the sample.

According to the present invention, since the container is filled with a mixed gas having high dielectric strength, an electrical test can be performed without using a SF ₆ gas and without flashing even at a relatively high voltage. In addition, since the mixed gas has a significantly low global warming potential and a complicated operation such as a gas recovery operation in the case of SF ₆ gas is not required, the test time can be greatly shortened.

It is a figure which shows schematic structure of the electrical test apparatus which concerns on 1st Embodiment. It is a figure which shows schematic structure of the electrical test apparatus which concerns on 2nd Embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment]
FIG. 1 is a diagram showing a schematic configuration of an electrical test apparatus according to the first embodiment. An electrical test apparatus 1 shown in FIG. 1 is a facility for performing a commercial frequency withstand voltage test using, for example, an electrical component such as a bushing (cannon) or an epoxy seat as a sample TS.
As shown in FIG. 1, the electrical test apparatus 1 includes a test container 10, a voltage application unit 20, a bubbling unit 30, and a gas supply unit 40.

The test container 10 is a container made of polycarbonate, for example. The test container 10 includes a storage portion 11 that stores the sample TS and a lid portion 12 that closes the opening of the storage portion 11.
The accommodating part 11 and the cover part 12 are closely_contact | adhered via sealing members 13, such as rubber packing. Thereby, it can prevent that the gas in the test container 10 leaks from the contact part of the accommodating part 11 and the cover part 12 remarkably.

However, the lid portion 12 is merely placed on the housing portion 11 via the seal member 13, and is not crimped by tightening bolts or the like in order to keep it airtight. In other words, in the present embodiment, the test container 10 is not intentionally kept airtight, and the gas (mixed gas IG described later) in the test container 10 is appropriately leaked from the contact portion between the housing portion 11 and the lid portion 12. Thus, moisture (humidity) is prevented from entering from the outside of the test container 10. Thereby, the humidity in the test container 10 is stabilized. In addition, since the test container 10 does not have a sealed structure, the replacement work of the sample TS is facilitated, so that the test efficiency is improved.
Note that the insulating gas (mixed gas IG) in the present embodiment has a low global warming potential as compared with SF ₆ gas, and is at a level that does not cause a problem even if it is released from the test container 10 to the atmosphere.

The sample TS includes, for example, a known bushing (cannula) including an insulator made of a high voltage electrode and an epoxy resin and an embedded metal fitting, and a known bushing including an insulator made of an epoxy resin and the embedded metal fitting. Epoxy seats are used.
A sample stage 14 for placing the sample TS is disposed in the test container 10. The sample stage 14 is a plate-shaped member made of stainless steel, for example. When the sample stage 14 is grounded, the embedded metal fitting of the sample TS placed on the sample stage 14 is grounded.
The sample stage 14 is fixed in a state where it is placed on a bubbling container 31 described later. In addition, the sample stage 14 has a large number of through holes 14a so that the mixed gas IG (insulating gas) generated in the bubbling unit 30 is also filled in the upper part of the test container 10 that becomes a charging unit when a voltage is applied. Is formed.

At present, there is no method for directly and accurately detecting the concentration of the mixed gas IG, but the concentration of the mixed gas IG in the test vessel 10 can be managed by adjusting the flow rate and temperature of the bubbling gas. . Moreover, the electrical test can be performed in a stable environment by disposing the hygrometer 50 (humidity detection unit) for detecting the humidity in the test container 10 in the test container 10.
Specifically, the relationship between the humidity in the test container 10 and the dielectric strength is acquired in advance. Experimentally, it was confirmed that it was flashed at 70 to 100 kV in the case of air insulation, whereas it was flashed at 150 kV when the gas mixture was filled with IG and the humidity was 3%. Yes. That is, in the case of an electrical test for an electrical component for 66/77 kV, when the humidity in the test container 10 becomes 3% or less, the mixed gas IG is contained in the test container 10 to the extent that it has the required dielectric strength. It can be judged that it is filled.

  The voltage application unit 20 includes a test transformer that can adjust the applied voltage. The test lead wire TL is drawn out from the voltage application unit 20, and this test lead wire TL is connected to one end of the high voltage electrode of the sample TS. In the case of a sample TS without a high voltage electrode such as an epoxy seat, a shield electrode is attached to the sample TS. In this case, the test lead wire TL is connected to one end of the shield electrode. The voltage application unit 20 applies a voltage to the sample TS via the test lead wire TL.

The gas supply unit 40 is a gas cylinder that supplies bubbling gas to the bubbling unit 30. Examples of the bubbling gas include nitrogen (N ₂ ) gas, dry air (nitrogen: about 80%, oxygen: about 20%), oxygen (O ₂ ) gas, carbon dioxide (CO ₂ ) gas, and argon (Ar) gas. Alternatively, an insulating gas containing no moisture (H ₂ O) such as helium (He) gas can be used. In particular, since nitrogen gas can be obtained at a low cost, it is suitable as a bubbling gas used in large quantities for electrical tests.
The gas supply unit 40 supplies the bubbling gas to the bubbling unit 30 (the bubbling plate 32) at a predetermined flow rate, for example, via a gas supply pipe 41 inserted through a through hole formed in the side wall of the housing unit 11. The gas supply pipe 41 and its tip (nozzle) are formed of a material that does not swell with a fluorine-based liquid used as the insulating solution IL. A sealing process is applied to the insertion portion of the gas supply pipe 41.

The bubbling unit 30 includes a bubbling container 31 and a bubbling plate 32.
The bubbling container 31 contains an insulating solution IL having a high insulating property. As the insulating solution IL, for example, a fluorine-based liquid (for example, Fluorinert (registered trademark) or hydrofluoroether), silicone oil, synthetic oil, or the like is suitable. In particular, Fluorinert (registered trademark) is a fluorine-based inert liquid that hardly undergoes a chemical reaction and has a high dielectric strength, and thus is more preferable as the insulating solution IL.

The bubbling plate 32 is, for example, a stainless plate member (for example, a disk member), and has a porous structure. The bubbling plate 32 is set at the bottom of the bubbling container 31 by attaching, for example, a metal serving as a weight to the periphery. The bubbling plate 32 has fine holes (porous structure) on the entire surface, and generates fine bubbles B when a bubbling gas is sent. When the generated bubble B rises in the insulating solution IL, an insulating component (for example, fluorine) dissolved in the insulating solution IL is vaporized and taken into the bubble B, and ruptures at the liquid surface of the insulating solution IL. A mixed gas IG composed of a bubbling gas and a vaporized insulating component is generated and filled in the test container 10.

As described above, in the electrical test apparatus 1, the bubbling unit 30 is disposed in the test container 10, and the mixed gas IG generated by the bubble B bursting on the liquid surface of the insulating solution IL is filled in the test container 10. The
Thereby, compared with the case where the bubbling part 30 is installed outside the test container 10 (see FIG. 2), the electrical test apparatus 1 can be reduced in size, and the mixed gas IG can be efficiently used in the test container 10. Can be filled well.

  When a commercial frequency withstand voltage test is performed using the electrical test apparatus 1, the sample TS is placed in the test container 10 in which the bubbling portion 30 and the sample stage 14 have been placed (first step). Further, the test lead wire TL is connected to the sample TS, and the lid 12 of the test container 10 is closed. At this time, the inside of the test container 10 is filled with air.

Next, the bubbling unit 30 is operated to fill the test container 10 with the mixed gas IG (second step). Specifically, the valve of the gas supply unit 40 is opened, and a bubbling gas (for example, nitrogen gas) is supplied to the bubbling unit 30. At this time, the flow rate and temperature of the bubbling gas are appropriately adjusted.
When the bubbling gas is introduced into the insulating solution IL through the bubbling plate 32, countless bubbles B are generated in the insulating solution IL. When the bubbles B rise in the insulating solution IL, the insulating component (for example, fluorine) dissolved in the insulating solution IL is vaporized and taken into the bubbles B. Then, the bubbles B are ruptured at the liquid surface of the insulating solution IL, and a mixed gas IG composed of a bubbling gas (for example, nitrogen gas) and a vaporized insulating component (for example, fluorine) is filled in the test container 10.

  At this time, the temperature of the bubbling gas is preferably managed at a temperature necessary for vaporizing the insulating solution IL when the bubbling gas is introduced into the insulating solution IL. This temperature includes the amount of bubbling gas in the gas cylinder that is the gas supply unit 40, the flow rate of the bubbling gas supplied from the gas supply unit 40 (gas cylinder) to the bubbling unit 30 (bubbling plate 32), and the atmosphere. It is adjusted appropriately according to the temperature.

As the test container 10 is filled with the mixed gas IG, the air initially filled in the test container 10 is exhausted from the gap between the accommodating portion 11 and the lid portion 12 and replaced with the mixed gas IG. Since the mixed gas IG does not contain moisture, the humidity in the test container 10 decreases according to the filling rate of the mixed gas IG. When the detection result of the hygrometer 50 (humidity detection unit) is equal to or lower than a predetermined humidity (for example, 3% or less), it is determined that the mixed gas IG is filled to such an extent that it has a dielectric strength necessary for the electrical test.
Since it can be known at an early stage that the inside of the test container 10 is filled with the mixed gas IG having high dielectric strength, the test time can be shortened.

  If the bubbling is stopped at this time, the mixed gas IG leaks from the gap between the accommodating portion 11 and the lid portion 12, and the dielectric strength may be reduced. Therefore, bubbling is continued even after the detection result of the hygrometer 50 (humidity detection unit) becomes equal to or lower than the predetermined humidity. In addition, since the dielectric strength in the test container 10 should just be hold | maintained, it is good also considering the flow volume of the gas for bubbling as compared with the time of filling with mixed gas IG.

In the present embodiment, the test container 10 is not kept airtight, and the mixed gas IG in the test container 10 is appropriately leaked from the contact portion between the housing portion 11 and the lid portion 12, so In order to prevent moisture (humidity) from entering. Thereby, the humidity in the test container 10 is stabilized. In addition, the mixed gas IG has a lower global warming potential than SF ₆ gas and is at a level that does not cause a problem even if released to the atmosphere. Is facilitated.

  Specifically, when the lid 12 is fixed to the housing 11 in an airtight manner, a plurality of bolts are necessary, and each time the sample TS to which the voltage is applied is replaced, a plurality of bolts must be attached and detached. Therefore, a predetermined work time is required. However, when the lid portion 12 is merely placed on the accommodating portion 11 as in the present embodiment, only the opening / closing operation of the lid portion 12 is required, so that a plurality of bolts for airtight fixing are attached. -Removal work becomes unnecessary. Moreover, since it does not fix airtightly, the cover part 12 can be formed with a lightweight material, and the opening / closing operation | work itself of the cover part 12 can also be performed easily. Therefore, the test time can be greatly shortened.

  Then, a voltage is applied to the sample TS by the voltage application unit 20 to measure electrical characteristics (here, as an example, commercial frequency withstand voltage) (third step). Since the inside of the test container 10 is filled with the mixed gas IG having a high dielectric strength, the electrical test can be stably performed without generating an air discharge or a surface flash.

  As described above, the electrical test apparatus 1 introduces the bubbling gas into the insulating solution IL, the test container 10 that stores the sample TS, the voltage application unit 20 that applies a voltage to the sample TS stored in the test container 10. Then, bubbles B are generated, the insulating components dissolved in the insulating solution IL are vaporized in the bubbles B, and the bubbling unit 30 for filling the test container 10 with the mixed gas IG composed of the bubbling gas and the vaporized insulating components. And a gas supply unit 40 for supplying a bubbling gas to the bubbling unit 30.

  Further, the electrical test method using the electrical test apparatus 1 includes the first step of placing the sample TS in the test container 10 and the introduction of bubbling gas into the insulating solution IL to generate bubbles B. A voltage is applied to the sample TS, a second step of vaporizing an insulating component dissolved in the IL in the bubble B, and filling the test vessel 10 with a mixed gas IG composed of a bubbling gas and the vaporized insulating component. And a third step of measuring electrical characteristics.

According to the electrical test apparatus 1 and the electrical test method using the same, the test container 10 is filled with the mixed gas IG having a high dielectric strength, so that it is relatively high without using SF ₆ gas having a high global warming potential. Electrical tests can be performed without flashing even with voltage. Therefore, the electrical test apparatus and the electrical test method are environmentally friendly and extremely useful for preventing global warming.

In addition, the mixed gas IG has a significantly low global warming potential, and a complicated operation such as a gas recovery operation in the case of SF ₆ gas is not required, so that the test time can be greatly shortened.
Conventionally, when the test vessel 10 of about 700 liters filled with SF ₆ gas for electrical test, about 10 minutes to fill the SF ₆ gas, it takes about 15 minutes for the recovery of SF ₆ gas after the test It was. On the other hand, in this embodiment, the filling time is about 1/10 to 1/5 as compared with the case of SF ₆ gas, and the collection time after the test is not required. It can be shortened.

[Second Embodiment]
FIG. 2 is a diagram showing a schematic configuration of the electrical test apparatus 2 according to the second embodiment. In FIG. 2, the same or corresponding components as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

As shown in FIG. 2, in the electrical test apparatus 2, the bubbling unit 30 is installed outside the test container 10. That is, the bubbling unit 30 is disposed outside the test container 10, and the mixed gas IG generated when the bubbles B burst on the liquid surface of the insulating solution IL is supplied to the test container 10 through the pipe 33 and filled. .
Thereby, as compared with the case where the bubbling unit 30 is installed in the test container 10 (see the first embodiment), the insulating solution IL can be easily replenished / replaced. When the electrical test of the sample TS is performed, the working efficiency is improved.

Similarly to the first embodiment, according to the electrical test apparatus 2 and the electrical test method using the electrical test apparatus 2, the inside of the test container 10 is filled with the mixed gas IG having a high dielectric strength. Therefore, the electrical test can be performed without flashing even at a relatively high voltage without using high SF ₆ gas. Therefore, the electrical test apparatus and the electrical test method are environmentally friendly and extremely useful for preventing global warming.
In addition, the mixed gas IG has a significantly low global warming potential, and a complicated operation such as a gas recovery operation in the case of SF ₆ gas is not required, so that the test time can be greatly shortened.

As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the present invention is not limited to the above embodiment, and can be changed without departing from the gist thereof.
For example, since the bubbling plate 32 only needs to be immersed in the insulating solution IL, a plurality of bubbling plates 32 may be erected in parallel in the bubbling container 31. A plurality of bubbling units 30 may be installed. As a result, the mixed gas IG can be efficiently supplied into the test container 10, and the filling time of the mixed gas IG can be shortened.
Further, a plurality of samples TS may be connected to the test lead wire TL so that the electrical test can be performed on the plurality of samples TS simultaneously.

  Moreover, it is good also as a structure which can hold | maintain the test container 10 airtightly. Thereby, since the pressure in the test container 10 can be made high, the dielectric strength of mixed gas IG can further be improved. In this case, since it is necessary to exhaust air until the inside of the test container 10 is filled with the mixed gas IG, the test container 10 is provided with an exhaust valve. In addition, bubbling is stopped after the gas mixture IG is filled. Therefore, consumption of the bubbling gas can be further reduced.

  Whether or not the mixed gas IG is sufficiently filled from the volume of the test container 10 and the bubbling efficiency (such as the flow rate of the bubbling gas and the bubbling time) without providing the hygrometer 50 (humidity detector) in the test container 10. You may make it judge.

  The present invention can be applied to an electrical test for measuring various electrical characteristics such as a commercial frequency partial discharge test and a lightning impulse withstand voltage test in addition to the commercial frequency withstand voltage test shown in the embodiment.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1, 2 Electrical test apparatus 10 Test container 11 Storage part 12 Cover part 13 Sealing member 14 Sample stand 20 Voltage application part 30 Bubbling part 31 Bubbling container 32 Bubbling plate 33 Pipe 40 Gas supply part 41 Gas supply pipe 50 Hygrometer (humidity detection) Part)
TL Test lead TS Sample IG Mixed gas (insulating gas)
IL Insulation solution B Bubble

Claims (9)

A container for containing a sample;
A voltage application unit for applying a voltage to the sample contained in the container;
A bubbling gas is introduced into the insulating solution to generate bubbles, and an insulating component dissolved in the insulating solution is vaporized in the bubble to generate a mixed gas composed of the bubbling gas and the vaporized insulating component. And a bubbling portion that fills the container with the mixed gas,
An electrical test apparatus comprising: a gas supply unit configured to supply the bubbling gas to the bubbling unit.   The electrical test apparatus according to claim 1, wherein the bubbling portion is disposed in the container, and the mixed gas is filled in the container.   The electrical test apparatus according to claim 1, wherein the bubbling portion is disposed outside the container, and the mixed gas is filled into the container through a pipe.   The electrical test apparatus according to any one of claims 1 to 3, further comprising a humidity detection unit that detects humidity in the container. The insulating solution is a fluorine-based liquid,
5. The electrical test apparatus according to claim 1, wherein the bubbling gas is an insulating gas. 6. A first step of placing a sample in a container;
Bubbling gas is introduced into the insulating solution to generate bubbles, the insulating component dissolved in the insulating solution is vaporized in the bubbles, and the mixed gas composed of the bubbling gas and the vaporized insulating component is A second step of filling the container;
And a third step of measuring electric characteristics by applying a voltage to the sample. In the second step, the humidity in the container is measured,
The electrical test method according to claim 6, wherein the third step is started after the humidity in the container becomes equal to or lower than a predetermined humidity. In the second step, a fluorine-based liquid is used as the insulating solution,
The electrical test method according to claim 6, wherein an insulating gas is used as the bubbling gas.   The electrical test method according to claim 6, wherein nitrogen gas is used as the bubbling gas.

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