Evaluation on the Long-Term Operational Reliability of Closing Springs in High-Voltage Circuit Breakers

As a key energy storage component in high-voltage circuit breakers, closing springs are susceptible to stress relaxation, resulting in a decline in closing performance due to high operational loads, prolonged usage, and environmental factors. In this work, the 60Si2CrVA alloy steel springs used in 110 kV high-voltage circuit breakers were utilized to study their mechanical behaviors under various temperatures, salt spray corrosion, and repeated closing operations. It is found that the conditions of salt spray corrosion, and repeated closing operations demonstrate a slight impact on its stress loss, while the operation temperature above 70 °C will result in an apparent increase in the stress loss rate. A threshold for closing failure related to the spring’s stress loss rate was established, and a life prediction method based on an improved Arrhenius acceleration model was proposed. The results indicate that the calculated service life of the spring is approximately 27.09 years based on the stress loss rate threshold of 4.5%. This work provides a novel method to evaluate the long-term operational state and service life of closing springs in high-voltage circuit breakers.