Application of phasor measurement unit in adaptive protection for loss of excitation in a generator

In the era of Smart Grid, Synchronized Phasor Measurement Units (PMU)s have become a mature technology, as the data provided by them have proved to be reliable. In this work a PMU has been envisaged to be installed in a generating station, supervising the operating conditions of three generating plants and their protection against frequently occurring faults. In this proposed scheme the PMU will examine its applicability as an Intelligent Electronic Device (IED) in a generator protection and coordination during Loss of Excitation(LOE). In this scheme, the PMU will sense alternator terminal voltage, terminal current and power factor and implement an adaptive relaying algorithm if anyone of the generators develop a field failure. The work primarily focuses on the development of a protection and coordination algorithm functional from an embedded system (FPGA Based) which will detect the LOE condition in the faulted machine and optimally load the generator under fault, without infringing on its Generator Capability Curve (GCC), Steady State Stability Limit curve(SSSL). Therefore a conservative tripping as per the classical LOE relay is avoided, tripping takes place when the generator crosses the SSSL or the GCC(as the case maybe, examined in detail).