With the rise of oil-free medium-voltage switch, vacuum switch has been widely promoted and applied for its unique advantages. Over the years, due to the reasons of production technology and on-site use environment, some vacuum switches may leak to varying degrees in their vacuum interrupter during operation, and some may leak to the point where normal interruption is impossible in the normal life range. In this case, the interruption will occur abnormal interruption phenomenon and cause serious consequences. Most domestic vacuum switch accidents are caused by this reason. Therefore, it is very important to strengthen periodic or irregular detection of vacuum switch vacuum.

The traditional detection method is "voltage withstanding method", that is, when the vacuum switch is on and off, a certain voltage is applied between the static and dynamic contacts to detect the leakage current of the vacuum tube, so as to infer the quality of the vacuum tube. The advantages of this method are: simple operation; shortcomings are: the quality of the vacuum tube can only be qualitatively detected; and the vacuum degree can not be accurately distinguished between 10-4-10-1 Pa, so the development trend of leakage can not be judged (that is, how much leakage the same vacuum switch has compared with the previous one).

Since the early 1990s, Huazhong University of Science and Technology has begun to study the on-site quantitative measurement of vacuum degree in vacuum interrupter of vacuum switch. After nearly ten years'efforts, it obtained a patent in 1999 and realized the on-site quantitative measurement without disassembly. With the means of quantitative measurement, we can not only measure whether the vacuum degree of vacuum switch is in the normal range, but also, more importantly, we can roughly infer the service life of some vacuum switches with faster leakage speed by comparing the measured results over the years, so as to really prevent accidents.

The company's HYG-V vacuum switch comprehensive characteristics tester is an upgraded product which has been continuously improved after many field tests. The product has compact structure, light and compact type, shorter test time, higher reliability, stability, accuracy and better function.

1. Power supply: AC220V + 15%, 50Hz;

2. Measurement range: 10-4-10-1 Pa; maximum resolution: 10-5 Pa;

3. Electric field voltage: 20KV;

4. Voltage of magnetic field: 1600V;

5. Testing accuracy: 5%

6. Use environment: - 10 ~40 C;

7. Shape size: 460mm *335mm *330mm;>

8. Weight of main engine: 12kg.

1. It can quantitatively measure the vacuum in the interrupter of various types of vacuum switches.

2. There is no need to disassemble the vacuum switch in the field measurement.

3. The test results are accurate and reliable.

4. LCD Chinese character display, easy to operate;

5. It can save, print and view the historical test data of the test.

6. The instrument is equipped with RS232 communication interface, which can connect the computer and realize many functions such as controlling and operating the instrument through the computer.

7. The instrument is light in weight and easy to carry.

Testing principle

The instrument is measured by magnetron discharge method. Pull the two contacts of vacuum switch arc extinguishing chamber apart to a certain distance, apply electric field pulse high voltage, place the arc extinguishing chamber in solenoid coil or put the new electromagnetic coil outside the arc extinguishing chamber, and pass a large current to the coil, thus generating pulse magnetic field synchronized with high voltage in the arc extinguishing chamber. In this way, under the action of pulsed strong magnetic field and strong electric field, the charged ions in the arc extinguishing chamber move spirally and collide with the residual gas molecules to ionize. The ionic current generated is approximately proportional to the density of the residual gas, i.e. the vacuum degree. For different types of vacuum tubes (tubes), due to their different structures, the ionic currents are different under the conditions of the same contact distance, the same vacuum degree, the same electric field and magnetic field. The corresponding curves between vacuum degree and ion current can be calibrated by experiments. When the ionic current is measured, the vacuum degree of the tube can be obtained by inquiring the ionic current-vacuum curve of the tube.

In order to improve the sensitivity of conventional magnetron discharge test for vacuum degree of arc extinguishing chamber, it is necessary to remove the arc extinguishing chamber from the circuit breaker and place it in solenoid tube. In this way, the arc extinguishing chamber needs to adjust the mechanical parameters when re-installing circuit breakers, which requires a large workload and professional personnel. The arc extinguishing chamber can be surrounded by a new type of magnetic control coil from the side, so that the arc extinguishing chamber need not be dismantled. The single chip computer is used for synchronous control and data acquisition, which improves the sensitivity of field measurement of vacuum degree of arc extinguishing chamber.