High Impedance Differential Module
Use the HID module in conjunction with a high-speed overcurrent relay to provide three phase high impedance differential protection for substation busbars of any voltage level. Additionally, it can also be used to protect electrical machines like transformers, generators or motors against restricted ground faults.
Each HID module includes resistors that provide the associated high impedance relay with stability againstexternal faults, and varistors (MOV - Metal Oxide Varistors) in order to limit the secondary peak voltage below 2 kV during fault conditions.
Use the auxiliary contacts provided by an optional latching relay to short-circuit the resistors once the associated relay has tripped, to prevent the fault current from circulating through the resistors.
The HID front panel incorporates a Reset pushbutton to reset the latching relay once the fault has been cleared, in order to eliminatethe resistors short circuit.
Features & Benefits:
Protection & Control