On-line stator winding fault diagnosis in induction generators for renewable generation

Renewable generation systems are increasing its presence in electrical power systems. For this reason, it is more important than ever to count with reliable and secure generation systems. In this way, the use of on-line diagnostic techniques in the maintenance schemes can be useful. This paper is about on-line condition monitoring in induction generators for small hydro stations and wind farms. In particular, stator winding fault diagnosis is analyzed. Currently, there are diagnostic techniques that are used in induction motors, but they could be used in generators as well. This paper analyzes the induction generator characteristics and describes the appropriate diagnostic techniques. These techniques depend on the machine voltage. As most of the induction generators are low voltage machines, the diagnosis of stator winding faults will be based on the detection of inter-turn short circuits. Most of the inter-turn short circuit diagnostic techniques are noninvasive as they are based on voltage and line current monitoring.