Several different protection ways for earthfault are introduced and discussed from earth-faultprotection, zero-sequence protection, residual current protection and other aspects.
Commonly, by opening one switch and closing the other, two group equations are set up to measure rotor earth-fault resistance in the rotor earth-faultprotection with switch sampling principle.
切换采样转子一点接地保护，通过两个静态开关一开一合建立两组方程来求解接地电阻与位置。
3
The earthfaultprotection and protective electric devices of TT and TN system and the application conditions were analyzed.