Detection of Short Circuits in the Rotor Field Winding in Large Hydro Generator

A method for detecting inter-turn short circuit in the rotor field winding of a large hydro generator is presented. The proposed method is based on the use of two inductive probes installed at two different locations in the machine, exploiting therefore the existing magnetic symmetry. This latter consists of monitoring the algebraic sum of the two induced voltages of these two probes. The studied hydro generator has a rating of 310 MVA with 408 slots and 56 poles. Many advanced electromagnetic simulations based on finite element method were carried out in order to validate the proposed approach. The simulation results were compared to the experimentally measured data collected of the considered generator and obtained respectively at no-load and rated load.