Detection of power transformer winding deformation and variation of measurement connections using a hybrid winding model

This paper employs a hybrid model of a disc-type transformer winding for frequency response analysis (FRA) of winding deformation and measurement parameter influence. The model is based on multi-conductor transmission line (MTL) theories and treats every disc of a transformer winding as a transmission line. Three types of winding deformation and two types of measurement connection variation have been simulated by changing the values of the corresponding electrical parameters. Meanwhile, the frequency range of FRA is extended to 10 MHz. Various scenarios have been included in the simulation studies and two statistical indicators have been adopted in result analysis. Simulation studies have shown that winding deformation and measurement connection variation can be reflected in frequency response by changing certain parameters of the hybrid model. Simulation results also suggest the frequency ranges in which the failure modes are most distinguishable and their characteristics.

► Presentation of a hybrid model and comparison study with the lumped parameter model.
► A comprehensive study on frequency response characterization of winding deformation.
► Simulation of high contact resistance failure and lead deformation.
► Consideration of inductance change caused by radial winding movement.
► Combining statistical analysis with FRA for the analysis of simulation results.