A Review on Modelling of the Maximum Lagging Current Test Method of Salient Pole Synchronous Machines

Quadrature-axis reactance for various reasons comes into account as one of themost important parameters of salient pole synchronous machine. there are several commonstandard methods for measuring this parameter that also have been explained with somedetails in the standards, scientific papers and text books. one of these methods is themaximum lagging current test that is done simply at no-load, having a three phase voltagesource and applying very low power even for a high power machine. how this experimentis done is described at some references such as the books related to electrical machinery.this paper presents a detail analysis and description of the test and some simulation resultsregarding the performance of the machine during pole-slipping. it is shown when thereversal field current is increased very slowly, the transient of the pole-slipping commencesat load angle equal to 45 degrees or by a better language at 225 instead of zero which is thecommon opinion of almost all the previously published literatures. in this paper, arealistically developed analysis of the test is presented applying appropriate assumptions.the maximum lagging current test is then simulated applying a small salient pole machinewith the rated 31.5 kva using matlab/simulink. some simulation results areillustrated that prove correctness and validity of the new analysis and the proof describedby the present paper