Inductances Estimation of Synchronous Generator under Static and Dynamic Eccentricity Fault using Modified Winding Function Method

摘要

Winding function method, applied to a faulted synchronous generator, is modified, and used for on-line diagnosis of static and dynamic eccentricity. This modified winding function enables to compute the air- gap magnetic permeance accurately. Instead of two or three terms of the infinity permeance series a closed form equation is employed for permeance evaluation. This leads to a precise computation of the inductances of the faulted synchronous generator. In this paper, self inductances of the stator and rotor mutual inductance of two stator phases and the mutual inductance of rotor and stator are obtained and compared. Meanwhile, it is shown that the formation of static eccentricity leads to the increase of the amplitude, and dynamic eccentricity leads to the increase of the amplitude and occurrence of the distortion in the above-mentioned inductances. Since calculation of inductances is the most important step for fault diagnosis of the synchronous generator, the proposed method improves the on-line diagnosis of the fault. Inductances of a healthy and faulted synchronous generator are evaluated and compared for a 475 kW, 480 V and 60 Hz synchronous generator.