Detailed Introduction to 35kV Vacuum Circuit Breakers

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Detailed Introduction to 35kV Vacuum Circuit Breakers:

### Structural Features
- **Porcelain Column Structure**: Porcelain columns are used as supporting and insulating components, which have good insulation performance and mechanical strength. They can withstand the effects of high voltage and large current and are suitable for outdoor environments.
- **Vacuum Interrupter**: It is the core component. It utilizes a high vacuum degree to extinguish electric arcs and has the advantages of strong breaking capacity, long service life, being oil-free, gas-free, economical and environmentally friendly, reducing environmental pollution and maintenance workload.
- **Operating Mechanism**: Commonly, there are electromagnetic operating mechanisms and spring operating mechanisms. The electromagnetic operating mechanism has a simple structure and reliable operation, but it requires a relatively large operating current. The spring operating mechanism has the characteristics of a small operating power supply capacity, fast operation speed and the ability to be operated frequently.

### Working Principle
- **Closing Process**: When the operating mechanism receives a closing signal, the moving iron core of the closing electromagnet moves upward, pushing the closing trip rod to move upward, causing the closing half-shaft to rotate counterclockwise, releasing the constraint on the closing latch. The closing latch rotates counterclockwise under the pressure of the roller, releasing the energy storage maintenance. The cam located on the main shaft generates an impact force due to the contraction force of the closing spring, hitting the rocker arm on the manual energy storage shaft and transmitting it to the switch through the connecting rod, thus completing the closing operation.
- **Opening Process**: After the mechanism receives an opening signal, the moving iron core of the opening electromagnet moves upward, pushing the opening trip rod to move upward, causing the opening half-shaft to rotate counterclockwise, releasing the constraint on the opening latch. The opening latch rotates counterclockwise under the pressure of the roller, and the rocker arm rotates counterclockwise due to the thrust of the internal opening spring of the switch, thus completing the opening operation.

### Technical Parameters
- **Rated Voltage**: The rated voltage of a 35kV vacuum circuit breaker is usually 40.5kV, considering factors such as system voltage fluctuations and safety margins.
- **Rated Current**: Common rated currents include 630A, 1250A, 1600A, 2000A, 2500A, 3150A, etc., which can be selected according to actual load requirements.
- **Rated Short-Circuit Breaking Current**: Generally, it is 25kA, 31.5kA, 40kA, etc. It reflects the breaking capacity of the circuit breaker in the event of a short-circuit fault and is one of the important indicators for measuring the performance of the circuit breaker.

### Models and Applications
- **ZW7-40.5**: It has a simple structure and high reliability. It is suitable for protection and control in the distribution systems of substations, industrial and mining enterprises. It can be operated frequently and can also be used as a sectional switch for power grids.
- **ZW32-40.5**: It has adaptability to high-altitude areas and is suitable for high-altitude regions. It can be configured in different types of switchgear cabinets and is used for the protection and control of single-bus electrical facilities. It can also be used in special occasions such as switching capacitor banks.
- **ZN85-40.5**: It has good breaking performance and is suitable for occasions with high requirements for breaking capacity, such as large substations and power plants.
- **ZN23-40.5**: It has the characteristics of small size, light weight and convenient operation. It is suitable for indoor switchgear cabinets and can be used for the protection and control of distribution systems in urban power grids, industrial and mining enterprises and other places.
- **ZN12-40.5**: It has stable and reliable performance and is suitable for various 35kV voltage level transmission and distribution systems. It can be used as a line circuit breaker, a tie circuit breaker, etc.

### Maintenance and Inspection
- **Daily Maintenance**: Regularly check the appearance to see if components such as the circuit breaker body, porcelain insulators and operating mechanisms are damaged, deformed or corroded. Clean the surface dirt to keep the equipment clean and hygienic. Check whether the bolts at the connection parts are loose, and if so, tighten them in time.
- **Regular Overhaul**: Conduct a comprehensive overhaul of the circuit breaker once every 1 to 3 years, including checking the vacuum degree of the vacuum interrupter, the wear condition of the contacts, the performance of the operating mechanism, etc. Lubricate and maintain the mechanism to ensure its flexible operation. Check and test the electrical control circuit to ensure the normal operation of the control circuit.
- **Fault Maintenance**: When the circuit breaker fails, it should be repaired in time. Common faults include failure to close, failure to open, air leakage in the vacuum interrupter, contact burning, etc. Faults can be diagnosed and repaired by checking the electrical circuit, mechanical components, vacuum degree, etc.