The Dissipation Factor (tan δ) Monitoring of A Stator Winding Insulation of A Synchronous Machine

the aim of this paper is to describe the dielectric loss tangent (tan δ) behaviors of the stator winding insulation of the 14.5 MVA 11kV synchronous machine from 2014–2017. This machine is still operated up to now. The tan δ values at different test voltages was measured and recorded. It was found that the sharp increase in tan δ values gave the sign of a significant degree of contamination and damage on the insulation surface which was proved by inspection. From the investigation the tan δ measurements is one of the effective ways to monitor and evaluate the insulation conditions of the stator insulation. The analysis and discussion of the existed problem of the synchronous machine are also included in this paper.