It is an important reformation that synchronous machine introduces brushless excitation,which canceled slide-ring and charcoal brush, while rotor windings'grounding faults detection is more difficult accordingly. At present, rotor windings' grounding detection for brushless synchronous electrical machine adopts conventional manner mostly,without considering its special structure.Aiming at this case,a sort of new principle of rotor windings' grounding detection for brushless synchronous electrical machine is put forward in this paper and its principle is analyzed in detail. The condition of eliminating grounding detection's dead area is put forward,and after dealing logically,sensitivity of grounding detection is unacted on excitation voltage.In addition, its influence towards grounding detection is also considered when the power systems burst with short fault, the simulational results prove that grounding detection didn't occur misoperation during bursting with short fault, which illuminates this sort of grounding detection with better reliability.The proposed new principle of grounding detection provides a certain theoretical reference basis for engineering applications of grounding detection for brushless synchronous electrical machine.%同步电机采用无刷励磁是同步电机结构上的重大改革,取消了滑环和炭刷,但使转子接地故障检测变得较困难.目前无刷同步电机转子绕组接地检测主要采用传统的方式,没有考虑到无刷同步电机的特殊结构.针对这一情况,提出了一种无刷同步电机转子绕组接地检测的新原理,详细地分析了它的接地检测原理.提出了消除接地检测死区的条件和接地检测的灵敏度不受励磁电压影响的方法.另外,还考虑了电网突然发生短路故障对接地监测的影响,仿真结果证明,在突然短路的过渡过程中,接地监测不会发生误动作,说明了该无刷同步电机接地监测具有较高的可靠性.该接地检测新原理为无刷同步电机接地检测的工程应用提供了一定的理论参考依据.
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