1. Fort Hare Institute of Technology, University of Fort Hare , Private Bag X1314, Alice 5700 , South Africa
2. Department of Physics, Renewable Energy Research Centre, University of Fort Hare , Private Bag X1314, Alice 5700 , South Africa
3. Department of Electrical and Electronic Engineering Science, Faculty of Engineering and Build Environment, University of Johannesburg , Auckland Park 2006 , South Africa