Application of Frequency Response Analysis for Diagnosis of Abnormality of Shunt Reactor

Summary

Frequency response analysis (FRA) is a powerful technique to detect abnormalities of windings of power transformers such as deformations and displacements of winding. FRA would be applicable to detect abnormality of shunt reactors because configurations of windings are similar to those of power transformers. In this study, FRA is applied to a shunt reactor. In the studied shunt reactor, acetylene gas was detected in dissolved gas analysis. In FRA, measured transfer functions are compared with those of a sister unit and a shift of a resonant frequency in the transfer function of the W phase is found. This indicates that the studied shunt reactor has some abnormality in the W phase. To investigate abnormality aspect, a circuit model of the shunt reactor is established. Transfer functions calculated using the circuit model agree with measured ones. The shift of the resonant frequency is reproduced when a rupture of an earth bar of the iron core, which sometime occurs in shunt reactors, is simulated in the circuit model. The studied shunt reactor is dismantled and rupture of an earth bar of the W-phase iron core is found. This is consistent with diagnosis by FRA and it is confirmed that FRA can also be applicable to diagnose of shunt reactors.

Additional informations

Authors

Van Coller John, Schutz Robert, Wang Yuanyuan