Optimization Procedure for Improvement of Thermal Interruption Capability of Tandem-puffer Interrupting Chamber

—90% SLF Interruption for the Rating of 63kA-50Hz—

Abstract

63kA-50Hz 90% short line fault (L90) is severer than 50kA-60Hz L90 from the points of view of electric endurance and interruption window. Interruption criteria and an optimization method of the chamber design are discussed to improve thermal interruption capability with it. The combination of the SA (Simulated Annealing) and MMFD (Modified Method of Feasible Directions) is applied to the optimization procedure. The optimized chambers with superior electric reliability are designed at 63kA-50Hz to improve gas density at current zero in thermal volume. 63kA-50Hz L90 interruptions are performed with the new chamber. In addition, influence of gas blast angle of nozzle on L90 interruption is clarified.