Effect of sequential 3-ph. fault on synchronous machine field transients

Abstract

In a synchronous machine with rectifier excitation, large reverse voltage may be induced across the field when following a disturbance, the field current tends to flow in the negative direction and is blocked by the rectifier. In this paper the effect of a sequential fault, in which subsequent to a line-to-line fault, a 3-ph. fault occurs after a small time delay, on the magnitude and duration of the field current in the reverse direction has been analysed. Investigations show that the sequential fault in this respect may be more unfavourable compared to line-to-line or simple 3-ph. faults. © Taylor & Francis Group, LLC.