In System Emulation (ISE) of a New Current Differentiall Back-Up Protection Relay

The philosophy, design, and evaluation of a wide area back-up differential protection scheme are described in this paper. In the absence of a commercially available relay capable of servicing the back-up function the back-up relay is "emulated" on a DSP in a real time digital simulator and coordinates with commercially available primary protection relays interfaced to the power system simulation running on the simulator. The scheme is evaluated on a small closely coupled power distribution system.