Exceeding the resistance of the main circuit of the circuit breaker is a major problem in today's power system. As the core equipment of the power system, the circuit breaker has a certain error in it, which may affect the operation of the power system. As the dispatcher and system control of electric energy distribution in the power system, the circuit breaker is also the core operating equipment of the entire power system. And during the operation of the main circuit resistance of the circuit breaker, the reliable performance and stable performance are directly related to the power supply form of the entire power system.

The resistance of the circuit breaker's conductive circuit mainly depends on the contact resistance between the moving and static contacts of the circuit breaker. The presence of contact resistance increases the loss of the conductor when it is energized and increases the temperature at the contact. Its value directly affects the current-carrying capacity during normal operation, and to a certain extent the short-circuit current cut-off ability. Therefore, the resistance value of each phase of the circuit breaker is an important data for the installation, maintenance and quality acceptance of the circuit breaker.

Therefore, in the process of the continuous development of my country's power system, the power industry should pay great attention to the cause of the circuit breaker's main circuit resistance to exceed the standard, and use effective means to comprehensively deal with the circuit breaker's main circuit resistance to ensure the maximum extent. The safe and stable performance of the main circuit resistance of the circuit breaker ensures the normal operation of the main circuit resistance of the circuit breaker.