Analysis of Shaft Voltages and Circulating Currents in the Parallel-Connected Windings in Large Synchronous Generators

Maintenance of large generators is important for safe and good operation of nuclear power plants. To improve this maintenance, we are developing a new diagnostic tool by means of electrical variables analysis. Our research was first made on shaft voltage analysis, then it has concerned neutral voltages, excitation current, and currents in parallel-connected windings. This study consists of simulations with a finite element method program and measurements on a laboratory synchronous machine and on large turbo-generators.