GETTING STARTED
1.4
HID OVERVIEW
High Impedance Differential protection is a well-known principle where stabilizing resistors provide immunity against
external faults. HID modules provide resistors together with voltage limiters (MOV) to be used with a high-speed
overcurrent relay in order to obtain a high impedance differential protection scheme. External CT's are differentially
connected exactly as for traditional high impedance differential protection relaying.
FIGURE 1-4 TYPICAL APPLICATION OF AN HID AS A BUSBAR DIFFERENTIAL PROTECTOR
GEK-113064
HID High Impedance Differential Module
1-5