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Vacuum test to determine the degree of vacuum vacuum vacuum vacuum switch the size of a direct impact on the vacuum switch extinguishing performance is good or bad, the vacuum degree will cause the vacuum switch to operate with adverse consequences. Ministry of Machinery Industry Standard JB/DQ2184-1986 "General Technical Conditions for Vacuum Interrupters for 3 ~ 35kV Vacuum Circuit Breakers" Section 2.2.13 and Electric Power Standard DL403-1991 "Technical Conditions for Ordering 10~35kV Indoor Vacuum Circuit Breakers" Section 2.13 Article stipulates that the vacuum degree of 10~35kV vacuum circuit breaker shall not be lower than 6.6×10-2Pa.  At present, the method of checking whether a vacuum bulb leaks is a power frequency voltage proof method, but many things show that the vacuum bulb through which the power frequency withstand voltage does not mean no leakage, and the most effective method is to detect the vacuum degree. The ZKD-V vacuum tester used by the Guangzhou Electric Power Bureau in recent years to detect vacuum leaks has played a positive role in guiding the overhaul of the vacuum switch and ensuring the safe operation of the equipment. 
1, the test principle
The principle of vacuum switch vacuum tester is: to open the arc extinguishing chamber two contacts to a certain distance, apply pulse high voltage, place the arc extinguishing chamber in the solenoid coil or place the new π-type coil in the extinguishing chamber On the outside, a large current is applied to the coil to generate a pulsed magnetic field synchronized with the high voltage in the arc chamber. In this way, under the action of a strong magnetic field and a strong electric field, the ions in the arc extinguishing chamber move spirally and collide with the residual gas molecules. The resulting ion current is approximately proportional to the residual gas density, that is, the degree of vacuum. For different vacuum tube models (tube type), because of their different structures, the ion currents are not the same size under the same contact distance, the same degree of vacuum, and the same electric field and magnetic field conditions. Through the experiment can be calibrated a variety of pipe vacuum degree and ion current correspondence curve. When the ion current is measured, the degree of vacuum of the tube can be obtained by querying the ion current-vacuum curve of the tube.  When testing the vacuum degree of the interrupter in the conventional magnetron discharge method, in order to increase its test sensitivity, the arc extinguishing chamber needs to be removed from the circuit breaker and placed in the solenoid coil. With the new π-type coil, the arc extinguishing chamber can be surrounded from the side so that it is not necessary to disassemble the arc extinguishing chamber. At the same time using 80C196 single-chip microcomputer for synchronous control and data acquisition and processing, improve the arc test chamber vacuum test sensitivity. 
2. Application of Vacuum Switch Vacuum Tester
2.1 The problem of vacuum switch In a power outage at a substation of Guangzhou Electric Power Bureau on December 7, 1999, accidentally discovered the 501 switches U and V of the low voltage side of the 10kV No. 1 transformer, the 503 switch U phase of the low voltage side of the 10kV No. 3 transformer, and the mother of the 10kV1. 500A switch W-phase vacuum bubble hair thickness, length (3 ~ 7cm), seems to scratch but also like a crack phenomenon, so the three vacuum switches fracture pressure test. All three vacuum switches passed the withstand voltage test standard of 42kV for 1 min. Are these three vacuum switches scratched on the surface or are they really cracked? We decided to use a vacuum tester to make measurements. 
2.2 Vacuum Tester Measurement We used the ZKD-V vacuum tester to measure the vacuum of the above three vacuum switches. The measurement results are shown in Table 1.   From Table 1, we can see that the 501 switch U-phase ion current and vacuum degree are obviously different from the other two-phase measurement results. The measured vacuum degree is 1.03×10Pa, which is obviously higher than the mechanical part's specified vacuum degree and cannot be lower than 6.6×. 10-2Pa standard, while the other phase measurement results meet the requirements. Therefore, we determined that there was a crack in the 501-switch U-phase vacuum bubble resulting in a leak, resulting in a drop in vacuum, while the others were scratched on the surface. Since these three switches are transformer low-voltage side or bus coupler switches, in order to not affect the power transmission work, according to the above measurement results, we decided to immediately replace the 501 switch, and other 503 and 500A switch will resume power transmission, this vacuum test It provided a certain basis for the restoration of power transmission at the time of the 503 and 500A switches. We also tested the replaced 501 vacuum switch and some new vacuum switches. The tested values ​​have some changes, but the order of magnitude is basically the same as the previous test result. The new vacuum bubble vacuum is generally lower than 10 - 4Pa magnitude. In 2000 and 2001, the Guangzhou Electric Power Bureau always used the ZKD-V vacuum tester as an aid for vacuum switch pretesting. In the vacuum switch withstand voltage test for the past two years, the Central Power Supply Bureau found scratches or cracks in the ceramic foam. After the withstand voltage test was passed, the vacuum bubble tester was used to retest the vacuum bubbles. The numerical values ​​are between 10-4Pa and 10-5Pa. We believe that scratches rather than cracks provide us with a reference criterion. At the same time, we also found that in the 10kV ceramic foam reformed without oil, the occurrence of scratches is relatively common, according to incomplete statistics about one-third, in particular, can not afford to skirt ceramic foam, due to just put into production At that time, no attention was paid to making records. These scratches may have originated in the process of overhauling and grounding the grounding wire. Most of the tests are based on the vacuum tester to determine if cracks or scratches occurred. 
From the initial application of this vacuum tester, it can be seen that: a) The U-phase vacuum from the 501 switch drops to 1î€03×10Pa. It can also withstand the fracture pressure test of 42kV for 1 min. Switch withstand voltage test can not pass 42kV, 1min fracture pressure test, the leak has been quite serious, and can withstand 42kV, 1min fracture pressure test vacuum bubble, can not prove that there is no vacuum bubble leak. Detecting the vacuum degree can more accurately reflect the operating status of the vacuum bubble. b) The ZKD-V vacuum tester measures the value of the vacuum degree of the vacuum bubble on the order of magnitude, and can determine whether the vacuum bubble in operation is leaking. c) At the same time, a substation of the Guangzhou Electric Power Bureau discovered that three large-current switches had cracks or scratches, and these three large-current switches all passed the fracture withstand voltage test and could not be judged as cracks or scratches. The degree of vacuum of the three vacuum switches was measured using a vacuum tester. Comparisons were made between the three switches to provide some effective criteria for determining whether cracks or scratches were occurring and whether or not the switch was replaced. This played a positive role.
Application of vacuum switch vacuum tester
The traditional way to judge whether a vacuum switch vacuum bulb leaks is through the AC withstand voltage test, but it turns out that using an AC withstand voltage test does not completely detect the vacuum switch vacuum bubble leakage, the most effective method is to detect the vacuum Bubble vacuum. To this end, a viable leak detection method was introduced—using a vacuum tester to measure the flow, and the principle and practical application of the vacuum tester was introduced. The practice shows that the vacuum tester can more accurately reflect the operating status of the vacuum bubble.