Potential of Type-1 Wind Turbines for Assisting With Frequency Support in Storage-Less Diesel Hybrid Mini-Grids

Diesel hybrid autonomous power systems (mini-grids) capable of operating with high penetration of wind usually require additional means to mitigate the impact of fluctuating wind energy on stability and power quality. The use of energy storage units and sophisticated wind turbines (WTs) with pitch angle control and/or a power electronics interface are deemed essential. They become costly and not economically attractive for many small remote communities with limited resources. This paper investigates the potential of inexpensive fixed-pitch directly coupled squirrel-cage-induction-generator-based (type 1) WTs for assisting with frequency stability and support in a storage-less diesel hybrid mini-grid. The impact of some parameters of the WT on the magnitude of the slope of its power-versus-frequency (droop) characteristics is examined. The results show that a type-1 WT with an increased droop slope can reduce frequency variations in the mini-grid as well as variations of power and torque in the diesel engine generator set.