How to check the vacuum degree of vacuum circuit breaker?
The vacuum degree test of vacuum circuit breaker is very important. Once the vacuum degree is destroyed, it will not be able to extinguish the arc, causing the circuit breaker to explode. There are several methods for vacuum inspection:
1. Appearance inspection method. If the vacuum arc extinguishing chamber is a glass shell, it can be judged according to the color of the barium getter film coated on the inner wall. If the vacuum degree is good, the film is in a mirror state; if the vacuum degree is poor, it is milky white. This method is not very accurate, but it can be used for reference.
2. Power frequency withstand voltage method. In the open state, the power frequency test voltage is processed between the fractures. If it can withstand more than 10s under the power frequency withstand voltage, it means that the vacuum degree is good. If the current increases during the voltage increase process, it is considered unqualified if it exceeds 5A. Of course, the breakdown during the withstand voltage process is also unqualified.
Precautions
Before the test, it is necessary to ensure that the circuit breaker is in the open state and the moving and static contacts are in good contact.
It can only roughly judge the situation of serious decrease in vacuum degree, and cannot accurately measure the leakage.
3. Magnetron discharge method
Test principle
The electric field distribution between contacts is measured by high-voltage pulses and synchronous magnetic fields to evaluate the vacuum degree. This method can be accurate to 0.066Pa and is currently the most reliable quantitative detection method.
Application scenarios
Applicable to scenarios where the trend of vacuum degree changes needs to be accurately evaluated, such as leakage monitoring.
4. Other auxiliary methods
Gas analysis
The vacuum state is judged by detecting the gas composition in the arc extinguishing chamber (such as the color change of barium getter). The color becomes gray or other abnormal gases appear, indicating that the vacuum degree has decreased.
Mechanical property test
Including short-circuit withstand test (such as 30-second short-circuit test) and current load test, which indirectly reflects the insulation performance of the vacuum arc extinguishing chamber.
Regular maintenance recommendations
Standard cycle: It is recommended that circuit breakers of 12kV and below be subjected to power frequency withstand voltage test every 1-3 years.
Leakage monitoring: If vacuum leakage is suspected, a vacuum tester should be used in time for accurate detection.
Professional equipment: It is recommended to use advanced equipment such as magnetron discharge tester to improve detection accuracy and efficiency.
The above method can effectively determine the vacuum state of the vacuum circuit breaker and ensure the safe and stable operation of the power system.
ZN42-27.5 railway-specific vacuum circuit beaker by Shaanxi West Power Tongzhong Electrical Co., Ltd.It is suitable for electrified railway power supply systems with a rated voltage of 27.5kV and single-phase AC 50Hz, and it serves as a special switch for breaking/making load and breaking fault current. It can be installed individually within a grid interval or mounted in a JYN-27.5 switchgear. The operating mechanism of this product is a spring energy storage type. It can be electrically operated by AC or DC power, or manually operated.
ZN42-27.5 railway-specific vacuum circuit beaker has many advantages:
1.Convenient maintenance
the modular mechanism design allows for easy replacement of the closing and opening coils without the need for dismantling other components. This eliminates the need for testing or adjustment after replacement, ensuring users to replace them independently, making subsequent maintenance more convenient.
2.High conductivity performance
the main conductive circuit adopts a high-performance vacuum interrupter, providing a long electrical life.
3.Supports intelligent customization
it can be specially equipped with online monitoring devices to enhance system stability.
