1. Power Systems Laboratory, Department of Electrical and Computer Engineering, Democritus University of Thrace, Xanthi, GR, Greece
2. Power Systems Laboratory, School of Electrical and Computer Engineering, Aristotle University of Thessaloniki, Thessaloniki, GR, Greece
3. Institute for Energy and Environment, Department of Electronic and Electrical Engineering, University of Strathclyde, G11QX Glasgow, Scotland, U.K.