Vacuum switch vacuum degree tester

Product actual shot

Vacuum switch vacuum degree testerProduct Overview

The JB87381998 "3.640.5KV AC High Voltage Switchgear Vacuum Extinguisher Chamber" formulated by the "National High Voltage Switchgear Standardization Technical Committee" stipulates that "internal gas pressure measurement and allowable storage period inspection" is a mandatory test item for units producing and using high-voltage switchgear vacuum interrupter chambers, and stipulates that the allowable storage period of the interrupter chamber is 20 years. The gas pressure inside the vacuum arc extinguishing chamber should be lower than 6.6 × 10-2Pa.
The commonly used method to determine whether the vacuum degree of a vacuum tube has deteriorated is the power frequency withstand voltage method, which can only determine the arc extinguishing chamber with severe vacuum degree deterioration. When the vacuum degree deteriorates to 10-2-10-1 Pa, although the breakdown voltage does not decrease, the arc extinguishing chamber is no longer qualified. Using a new type of excitation coil and magnetic discharge method to test the vacuum degree of the arc extinguishing chamber, there is no need to disassemble the arc extinguishing chamber. At the same time, a microcomputer is used for synchronous control and data acquisition processing, achieving a sensitivity of 10-5Pa for on-site testing of the vacuum degree in the arc extinguishing chamber. The outstanding feature of this instrument is the use of a new excitation coil and data processing method, which enables non disassembly measurement of vacuum degree. This instrument has the advantages of convenient use, easy operation, non disassembly measurement, and high testing accuracy. It is a practical detection instrument widely used in departments such as power, steel, petrochemicals, textiles, coal, railways, etc. that use vacuum switches.

Vacuum switch vacuum degree testertechnical indicators

1. Test object: Various types of vacuum switch tubes.
2. Testing method: A new excitation coil is used for non disassembly measurement of vacuum tubes.
3. Scope of application: This instrument is a multi-purpose type that can measure multiple types of vacuum switches.
4. Detection range: 10-510-1 Pa
5. Measurement accuracy: 10-510-4 Pa, 10%
10-410-3 Pa ， 10%
10-310-2 Pa ， 10%
10-210-1 Pa ， 10%
6. Magnetic field voltage: 1700V
7. Pulse electric field high voltage: 30KV
8. When testing the vacuum degree, the opening distance of the switch tube should be used normally.
9. Operating environment: -20 ℃~40 ℃
10. Host weight: 24kg
11. Dimensions: 410 × 320 × 370 (mm)
12. Sampler: Magnetron coil

Test Principle

Pull apart the two contacts of the arc extinguishing chamber by a certain distance and apply pulse high voltage; Place the arc extinguishing chamber inside the spiral coil or place the new electromagnetic coil outside the arc extinguishing chamber, apply magnetic field voltage to the coil, and generate a pulse magnetic field synchronized with high voltage inside the arc extinguishing chamber. Under the action of pulsed magnetic field and strong electric field, electrons in the arc extinguishing chamber undergo spiral motion and collide with residual gas molecules for ionization. The resulting ion current is proportional to the density of the residual gas (i.e. vacuum degree value). For different types of vacuum tubes (tube types), due to their different structures, the magnitude of ion current varies under the same contact distance, vacuum degree, electric and magnetic fields. The corresponding relationship curve between the vacuum degree of various tube types and the ion power source can be calibrated through experiments. After measuring the ion current, the vacuum degree of the tube type can be obtained by querying the ion current vacuum degree curve of the tube type. The schematic diagram of the test circuit is shown in the figure.

Vacuum degree, magnetic control degree, and discharge method testing circuit for arc extinguishing chamber

When testing the vacuum degree of the arc extinguishing chamber using conventional magnetron discharge method, in order to improve the testing sensitivity, the arc extinguishing chamber needs to be removed from the circuit breaker and placed inside the spiral tube coil. In this way, when reinstalling the arc extinguishing chamber onto the circuit breaker device, it is necessary to readjust the mechanical parameters, which requires a large amount of work and professional expertise. The use of a new type of magnetic coil can surround the arc extinguishing chamber from the side, so there is no need to disassemble the arc extinguishing chamber. Simultaneously using a single-chip microcomputer for synchronous control and data acquisition processing has improved the sensitivity of on-site testing of the vacuum degree in the arc extinguishing chamber.

Precautions

1. It should be carried out in clear and dry weather, and the surface of the vacuum bubble should be wiped clean. Leakage caused by dirty surface of the vacuum bubble will seriously affect the actual test results of the vacuum degree. The vacuum degree test of the same vacuum switch should have a minimum interval of 10 minutes between each test. Otherwise, the ionized air inside the tube may not be able to recover to its normal state in time, resulting in distorted test results.
2. It is recommended not to conduct vacuum degree tests on the same vacuum switch more than 3 times a day.
3. When testing the vacuum degree, leak detection should be conducted first, and quantitative testing should only be carried out after the leak detection is qualified.
4. When installing the excitation coil, its positioning indicator line points to the middle gap of the arc extinguishing chamber connection.
5. During the testing process, the human body should not come into contact with the high voltage and magnetic field voltage output terminals, and the casing of the tester should be grounded.
6. The high-voltage output line and ion current line should be separated to prevent interference.
7. The magnetic field voltage line must be short circuited quickly, otherwise it will seriously damage the instrument and personal safety! Before the experiment, the yellow green wire must be connected to the electromagnet first and then to the instrument; After the experiment, pull out the yellow and green test wires from the instrument separately (do not touch the exposed part of the plug with your hand).
8. After the test is completed, the power should be turned off and the high-voltage output terminal should be short circuited and discharged to ground to avoid being electrocuted by residual voltage on the charging capacitor.