详细介绍：
The NPIH 800 and NPIHD 800 relays protect three-phase electrical networks against phase to earth faults. In addition,the NPIHD 800 features a directional function.
ANSI FUNCTIONS FOR NPIH 800 :
51N / 50N / 86 / 74TC / 50N_BF
ANSI FUNCTIONS FOR NPIHD 800 :
51N / 50N / 67N / 86 / 74TC / 50N_BF
