master policy是什么意思

用法例句

Through analyzing an actual construction engineering,it was illuminated that general protection switch and loop switch of transformer adopting quadrupole circuit breaker had evident defects.

通过一个具体建筑工程的实际案例分析,说明变压器总保护开关和联络开关采用四极断路器有明显缺陷,导致有些情况下供电系统方案难以实施,进而建议推广采用三极断路器。