Detecting Stator Winding Inter-Turn Short-Circuit in Tidal Stream Turbines by Relative Value Temperature Analysis

Tidal-stream electricity generation is in its infancy when compared to the wind turbine sector. Tidal-stream energy is predictable and can extract more energy per media unit due to the difference between wind and seawater densities. However, the commercialization of wind-energy systems is more advanced than that of tidal-stream. One of the main reasons for this is the fact that tidal-stream turbines, of necessity, must be deployed in a very challenging marine environment. Because of this, maintenance is an issue. Condition Monitoring (CM) is proposed in the literature as having the potential to contribute to a Condition Based Maintenance (CBM) strategy for tidal-stream turbines. An issue with tidal-stream turbines is Inter-Turn Short Circuits (ITSC) which occur in the stator windings of the generator. Several approaches are proposed in the literature for the detection of ITSC, temperature analysis being one method. The literature to date presents temperature monitoring techniques based on the absolute generator temperature value. Determination of the absolute temperature of a generator is challenging and is of rather limited value. In previous works by the Author, the relative as opposed to the absolute temperatures were proposed as having the potential to indicate the presence of ITSC. The relative temperature approach facilitates automatic compensation for environmental temperature and generator load conditions. This paper extends this methodology.