Novel technique to improve the fault detection sensitivity in transformer maintenance test

Abstract

AbstractEarly detection of incipient faults in transformer windings is important, so that required corrective measures can be taken to help prevent interruption during operation. Low voltage impulse (LVI) and sweep frequency response analysis (SFRA) tests have been widely adopted within the industry to determine a transformer winding's deformation. However, these tests have drawbacks, including limited frequency ranges for the LVI test and time‐consuming measurements for the SFRA test. To obtain better signature analysis in the transformer maintenance test, especially detection of minor faults, this paper suggests a new input signal using a pulse sequence (PS) in the transfer function (TF) analysis. The results of the PS test are compared against the LVI and SFRA tests to complete the assessments, which are derived from experimental works on the 25 kVA distribution transformer. It is concluded that the PS method improves fault detection sensitivity significantly. Copyright © 2009 John Wiley & Sons, Ltd.