Coupled fluid-mechanical analysis method in high-voltage circuit breakers design

Abstract

A coupled fluid-mechanical dynamics analysis method is presented in this paper. A commercial simulation package is used for mechanical dynamics calculation, which employs user-developed dynamic-link library files as routine interface to enable data exchange with gas pressure calculation. This part is responsible for the calculation of mechanical motion, including the tripping of trip trigger, releasing of main spring, rotation of main lever, motion of linkage assembly, and the motion of moving parts with gravity and moment of inertia taken into account. Besides these, the calculation with respect to the reaction force of oil-dashpot (ODP, damper) has been introduced, which has obvious influence on the latter half part of an actual travel curve. In addition, an in-house developed tool — LS Integrated CB Design Program works for the calculation of gas pressure in compression chamber. This tool also serves as the master program to control all procedures, including launching mechanical calculation and implementing the data exchange. Supported by the highly usable equation of state for SF6 gas, the running time of simulation for each case (no-load) could be reduced remarkably with sufficient accuracy for guiding design.