JPH0674853A - Method for testing leak of closed electrical equipment - Google Patents

Abstract

PURPOSE:To achieve a test in high-pressure state by heating an electrical equipment and measuring the leakage of an insulation medium after preventing deformation by housing a closed electrical equipment wherein the insulation medium is enclosed in a test container and then evacuate the inside of the container. CONSTITUTION:An electrical equipment 1 where an insulation gas is enclosed is adhered to a deformation-preventing material 7 in iron double structure and is housed in a test container 3, an upper lid 8 is closed, a valve 9 is opened, a vacuum pump 10 is driven, and then the inside of the container 3 is evacuated. When the inside of the container 3 is turned to a negative pressure, the lid 8 is sucked, thus preventing an external gas from being mixed into the container 3. Also, the pressure difference between the inside of the equipment 1 and the surrounding increases. When a specific degree of vacuum is reached, a switch 11 is turned on and a power supply 12 is connected to a heater 6. The insulation gas inside the equipment 1 is inflated due to heating and an inner pressure rises and the equipment 1 tries to be deformed toward the outside along with vacuum drawing. However, the deformation-preventing along material 7 tries to prevent deformation, thus achieving a leak test under a high-pressure state. The insulation gas after cooling is led to a leak detector 14 and the amount is measured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leak test method for sealed electric equipment.

[0002]

2. Description of the Related Art In sealed electrical equipment, for example, in a capacitor device in which an insulating gas is sealed in a case together with a capacitor element, a leak of the insulating gas inside may be tested. Therefore, the capacitor device is heated to expand the insulating gas. By doing so, the internal pressure of the capacitor device is increased, and the leaking insulating gas is measured.

Therefore, conventionally, as shown in FIG. 2, the condenser device 1 is put in a vinyl bag 2 and hermetically sealed, and then placed in a heating furnace to be heated. After the heating, it is cooled and taken out from the heating furnace, and the amount of the insulating gas leaked from the capacitor device 1 into the bag 2 is measured by the leak detector.

However, in such a leak test, it is necessary to perform the test by raising the internal pressure of the capacitor device as compared with the actual operation of the capacitor device. According to the conventional test method, when the internal pressure is increased, The case of the capacitor device 1 may be deformed, so that leak detection cannot be performed sufficiently.

Further, when the condenser device 1 is wrapped in the bag 2, there is a possibility that surrounding gas may be entrained, so that the detection result may be erroneously judged. Moreover, since such a bag 2 is used, the volume of the space to be measured is not fixed, which may cause a measurement error.

[0006]

DISCLOSURE OF THE INVENTION The present invention is a leak test of an insulating medium enclosed with an electric device sealed in a case, and the test is executed at a high pressure without causing deformation of the case. The purpose is to be able to.

[0007]

According to the present invention, a deformation preventing member is applied to a side surface of a case of a sealed electric device to be tested, which is filled with an insulating medium, and is stored in a test container. First, the test container is evacuated, then the test container is heated to heat the electrical equipment to increase the internal pressure, and then the insulating medium leaked into the test container due to the heating of the electrical equipment is measured. It is characterized by doing so.

[0008]

[Function] Since the inside of the test container is first evacuated, there is no risk of entraining external gas in the leak test, and the pressure difference between the inside of the electrical equipment and the surroundings should be made larger than that in the atmosphere. You can After that, the electric equipment is heated, and the heating increases the pressure inside the electric equipment. However, since the deformation preventing member is applied to the side surface of the electric device, the case of the electric device is prevented from being deformed. Therefore, the leak test can be performed in a state where the pressure inside the electric device is increased.

[0009]

Embodiment An embodiment of the present invention will be described with reference to FIG. 1
Is a sealed electric device to be tested, for example, a sealed capacitor device filled with an insulating gas as described above, 3 is a test container, and a machine that can withstand expansion when the capacitor device 1 is heated as described later. It is designed to maintain the desired strength. Specifically, the iron plate 4 having sufficient mechanical strength is constructed as a double structure.

A heat insulating material 5 is interposed between iron plates 4 having a double structure, and an electric heater 6 is installed.
Reference numeral 7 denotes a deformation preventing member, which is preferably heat-conductive and lightweight, and is preferably made of, for example, an aluminum plate. When the capacitor device 1 is housed in the test container 3, it is in close contact with the outer surface thereof. 8
Is the upper lid of the test container 3.

The capacitor device 1 is housed in the test container 3 so that its side surface closely contacts the deformation preventing member 7, and the upper lid 8 is closed. Then, for example, the upper lid 8 is pressed from above by a hydraulic cylinder, the valve 9 is opened, and the vacuum pump 1
By driving 0, the inside of the test container 3 is evacuated.

If the inside of the test container 3 becomes a negative pressure due to a certain degree of vacuum, the upper lid 8 will be sucked and fixed due to the difference from the atmosphere, so the upper lid 8 by the hydraulic cylinder will be fixed. You may stop holding down. By performing vacuuming in this way, it becomes possible to prevent external gas from being mixed into the test container 3 during the leak test, and the pressure difference between the inside and the outside of the electric device is the atmosphere. It can be larger than the case.

When the required vacuum degree is reached, the valve 9 is closed and then the switch 11 is closed to connect the electric heater 6 to the heating power source 12. As a result, the electric heater 6 generates heat, and the heat from this heats the capacitor device 1 via the deformation preventing member 7.

Due to this heating, the insulating gas in the capacitor device 1 expands and its internal pressure rises. Due to the heating and the vacuuming described above, the case of the capacitor device 1 tends to be deformed in the direction of expanding outward, but the deformation preventing member 7 prevents the deformation. Therefore, the internal pressure of the capacitor device 1 can be sufficiently increased without observing the deformation of the case. That is, the leak test is performed under high pressure.

When a predetermined internal pressure is reached, the switch 1
1 is opened to stop heating by the electric heater 6 and left to cool for a required time. After that, the valve 13 is opened, the insulating gas leaked from the capacitor device 1 into the test container 3 is guided to the leak detector 14, and the amount thereof is measured. The leak state of the capacitor device 1 can be detected from the measured value.

In the above description, the electric device to be tested is a capacitor device, but it may be any other electric device. Further, although the case where the insulating medium sealed inside is an insulating gas has been described, the present invention is also applicable to another insulating medium such as insulating oil.

[0017]

As described above, according to the present invention, in the leak test of the electric equipment, the test container in which the electric equipment is put for the test is first evacuated, so that the external gas Mixing is prevented, which makes it possible to avoid measurement errors due to mixed gas, and to make the pressure difference between the inside and the surroundings of electrical equipment larger than when the surroundings are in the atmosphere. Since the device is prevented from being deformed, even if the internal pressure of the electric device is sufficiently increased by heating, it will not cause deformation to the case of the electric device, and since such a test container is used. The internal volume is always constant, so that the measurement accuracy is extremely high.

[Brief description of drawings]

FIG. 1 is a view for explaining an embodiment method of the present invention,
It is sectional drawing of the test container used for the test.

FIG. 2 is a cross-sectional view showing a test state for explaining a conventional method.

[Explanation of symbols]

 1 Capacitor Device 3 Test Container 6 Electric Heater 7 Deformation Preventing Member 10 Vacuum Pump 12 Power Supply for Heating 14 Leak Detector

Claims (1)

[Claims] 1. A test container in which a deformation preventing member is applied to the side surface of a case of a sealed electric device to be tested, which is made by enclosing an insulating medium, is first stored in the test container. A vacuum is applied, and then the test container is heated to heat the electric device to increase the internal pressure, and then the insulating medium leaked into the test container due to the heating of the electric device is measured. Leak test method for sealed electrical equipment.