Simulation Research on Breaking Performance of 550kV 80kA SF₆ Circuit Breaker under Different Opening Characteristics

With the continuous development of the power grid, the short-circuit current of the line is getting higher and higher. In some areas, the rated short-circuit current has been increased from 63kA to 80kA, which puts forward new requirements for the improvement of the breaking performance of the existing 550kV circuit breakers. In order to develop the arc chamber of 550kV 80kA circuit breaker and analyze the influence of different opening characteristics on the breaking performance, this article is based on the existing mathematical model of the arc breaking process of circuit breakers, and analyzes the breaking process under the two opening characteristics of 230mm and 260mm. A simulation calculation was carried out. The pressure of the arc extinguishing chamber during the breaking process is obtained, and the air flow field parameters such as the pressure, temperature and axial velocity of the arc extinguishing chamber at the current zero time are obtained. The breaking performance of the interrupter at two opening speeds is compared, which lays the foundation for the subsequent optimization design. Through analysis, it is found that in the breaking process, compared with the 230mm case, the 260mm case has a stronger breaking performance. Therefore, increasing the travel and increasing the opening speed, especially the opening speed near the current zero-crossing moment, can effectively improve the breaking performance of the circuit breaker, which provides a reference for the subsequent structural optimization design and travel characteristics matching of the interrupter.