Influence of Cross-Sectional Interface Areas on Interruption Performance in High-Voltage Self-Extinguishing Extinguishing SF₆ Circuit Breakers

With the development of power grids, the interrupting performance of high-voltage self-extinguishing SF<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</inf>circuit breaker faces challenges. This paper conducts theoretical analysis of the enthalpy flow physical model and valve motion equations of the circuit breaker, supplemented by HVCB software simulations. The results indicate that the circuit breaker can successfully interrupt the current under medium and short arcing time conditions when the expansion chamber pressure reaches 1.370 MPa and the mass flow rate between the chamber and arc exceeds 2.126 kg/s. When the interface area between the compression chamber and expansion chamber varies from 100 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> to 2500 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>, the pressure and mass flow rate in the expansion chamber first increase and then decrease. When the connecting area between the cooling chamber and adjacent chambers varies from 9000 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> to 16000 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>, the pressure and mass flow rate in the expansion chamber remain essentially stable. This study reveals the intrinsic correlation between interface area and interrupting performance, providing theoretical guidance for the optimized design of high-voltage self-extinguishing SF<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</inf>circuit breakers.