1. Advanced High Voltage Engineering Research Centre, School of Engineering, Cardiff University,Cardiff,U.K.,CF24 3AA
2. Electrical Engineering and Computer Science, Khalifa University,Abu Dhabi,UAE,PO Box 127788
3. Kingsmill Industries (UK) Limited,Derbyshire,U.K.,NG16 6NS
4. College of Life and Environmental Sciences, University of Exeter,Exeter,U.K.,EX4 4QL