Fast and secure detection technique for loss of field occurrence in synchronous generators

Abstract

Loss of field (LOF) phenomenon in synchronous generators may cause serious damages and voltage drop in the power system, which can result in a blackout. Conventional methods, which detect LOF on the basis of the measured impedance from terminal viewpoint, are slow and may exhibit mal-operation in the face of other phenomena, e.g. stable power swing (SPS). In this paper, a novel technique is proposed to detect LOF in synchronous generators on the basis of some electrical quantities variations including voltage of terminal (V), current (I), active power (P), reactive power (Q) and power angle (δ). To evaluate the performance of the proposed algorithm, some cases are simulated under various operation conditions. Obtained results show that this algorithm on the basis of V, Q and δ not only can be considered as a fast LOF detector in comparison with the conventional impedance-based schemes, but also it is a robust and secure technique in the face of SPS and other power system disturbances. The proposed algorithm is tested by using an experimental setup including the laboratory synchronous generators, too. The obtained results show that the proposed technique can exhibit suitable performance in the actual conditions.