A method for evaluating the comprehensive degradation of circuit breakers based on current curves

The performance of high-voltage circuit breakers deteriorates over time due to environmental factors such as temperature, humidity, and salt fog, which affect key components such as the hydraulic system and action core. This study describes the degradation process of circuit breakers under different operating conditions through variations in coil current. Thermal-humidity tests were conducted to investigate the impact of temperature and humidity on the overall performance of the circuit breaker. Additionally, alternating salt fog tests were used to assess the combined effect of temperature, humidity, and salt fog on the comprehensive reliability of the circuit breaker. Furthermore, this paper includes experimental analysis based on operational data of circuit breakers from a real power grid in northern China, along with relevant regulations. The numerical results show that performance degradation in a thermal-humidity environment follows an abrupt change pattern, while in a salt fog environment, the degradation exhibits a nonlinear acceleration process.