Research on the airflow field and interruption performance of 550 kV fast circuit breaker

Abstract

Abstract The fast circuit breaker can achieve the rapid removal of short-circuit faults, which is of paramount significance for ensuring the safe and stable operation of the power system. This paper proposes a design scheme for the arc extinguishing chamber of the 550 kV fast circuit breaker, establishes a mathematical model of magneto-hydro-dynamics (MHD) arc, and calculates the trends of gas pressure, arc temperature, and nozzle airflow velocity inside the fast interruption arc extinguishing chamber under different arcing times. It compares and analyzes key interruption parameters such as airflow field characteristics, arc conductance, and post-arc current, researches the interruption performance of fast circuit breakers under different arcing times, and determines the prototype design scheme. It is found that the design scheme of the arc extinguishing chamber with the opening speed of 13.5 m s−1, inflation pressure of 0.6 MPa, overtravel of 33 mm, cylinder radius of 80 mm, and nozzle throat length of 27 mm can compress the short arcing time to 6 ms, while maintaining good interruption performance for medium and long arcing, meeting the requirements of fast interruption. The prototype successfully passed the T100(s) interruption test, achieving a short arcing time of 6.2 ms, as well as corresponding medium and long arcing interruptions, verifying the effectiveness of the simulation calculations. The 550 kV fast circuit breaker successfully reduced the total interruption time to within 25 ms, and the research results successfully guided the development of the fast circuit breaker prototype.