Can helium mass spectrometer leak detector be applied to detect leaks in high-voltage switch casings?
Helium mass spectrometer leak detector is widely used in medium voltage switchgear in the power industry, including power plants, substations, regional power grids, and transmission stations. It is also applicable to industries such as shipping and high-speed rail. Medium voltage switchgear is a type of metal enclosed switchgear that provides excellent insulation performance for equipment other than medium voltage switches, avoiding arc burning through power equipment and ensuring safety in power use. The interior of the medium voltage switchgear is controlled by suction and switch circuits.
The switch suction device needs to be leak checked
The internal control circuit of the medium voltage switchgear is controlled by suction and switch, and the vacuum environment inside the suction device. If there is leakage, the suction switch will fail, causing power interruption and leading to accidents. Therefore, leak detection is required.
The 220000 volt high-voltage substation is controlled by high-voltage switches (high-voltage circuit breakers) for opening and closing, among which the SF6 circuit breaker is insulated by filling it with insulating gas SF6. The circuit breaker itself needs to undergo leak detection to ensure that SF6 does not leak. During live operation, for dual safety considerations, a SF6 density meter is used to monitor SF6 leakage. Therefore, non-destructive leakage testing of the density meter itself is required.
A company engaged in the integration of power equipment and control systems used a helium mass spectrometer leak detector to detect sulfur hexafluoride density meters produced by them. According to the operating conditions and specifications of the density table, helium mass spectrometer leak detector is used for positive or negative pressure leak detection.
Taking negative pressure mode as an example, the leakage rate requirement is 10E-9mbar l/s.
1. The density meter is connected to the inlet of the leak detector, and the leak rate value and leak detection mode are set.
2. Use a spray gun to scan the weld seam and joint area of the density meter. If there is a narrow slit that exceeds the set leakage rate value, the leak detector will emit an audible and visual alarm in real time and display the leakage rate value on the screen.
Application of helium mass spectrometer leak detector in the power industry:
SF6 high-voltage switches and zinc oxide lightning arresters are important components of power plants and field transmission and transformation.
1) High voltage switches are made of aluminum castings in the connecting box, which often have sand holes and complex leakage structures, making them difficult to clean. Generally, the leak detection box or helium hood method is used, which involves evacuating the inspected item, filling the hood with helium gas, and waiting for a certain period of time to determine the total leak rate. Due to the small amount of helium used, the detection sensitivity is high.
2) Zinc oxide lightning arrester is a device that uses different cross-sectional areas, thicknesses, and quantities of zinc oxide sheets according to voltage requirements, installed in ceramic sleeves, filled with nitrogen gas, and sealed. Its working principle is that in the event of lightning strikes in high-voltage output, the resistance of the zinc oxide sheet decreases, causing a short circuit to ground due to high current and protecting the transmission line. If there is no pressure difference between the inside and outside due to leakage, external humid gases may enter and damage the characteristics of the zinc oxide sheet, causing an explosion.
3) In the power industry, helium mass spectrometer leak detectors are also used for leak detection in power plants, high-voltage transformers, high-voltage capacitors, high-voltage switch tubes, and other components, using different methods for leak detection.
Alright, the above is the introduction about how helium mass spectrometer leak detector can be applied to high-voltage switch housing leak detection. I hope it can help everyone~
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