GE / Alstom HID High Impedance Differential Module

GE HID High Impedance Differential Module : GE provides enhanced reliability through advanced protection for a wide range of bus protection applications. Our highly skilled technology teams understand bus bar principles and protection techniques, and use them to design, manufacture and support bus protection solutions that can be applied to a vast array of applications.
High magnitude fault currents require high speed operation of the bus bar protection to limit damage. However, this high speed clearing must be balanced against the need for security. Tripping incorrectly for an external fault may cause large outages and jeopardize power system stability. Learn more in our bus principles and protection guide.

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:
? Single-zone bus protection, reactor protection, or sensitive restricted earth fault protection on grounded, wye-connected power transformer windings
? Provides metal oxide varistors (MOV) to clamp secondary peak voltage to less than 2 kV

We offer GE?s century long tradition of power system innovation. From generators to transmission lines, to motors and beyond, we ensure dependable, safe power worldwide. GE offers a wide range of single function and auxiliary relays, along with a portfolio of accessories, to support high performing and reliable protection and control systems. To explore the GE portfolio with us click here GE numerical Relays !