D P Kothari is Professor, Centre for Energy Studies, and Deputy Director (Administration) Indian Institute of Technology, Delhi. He has also been the Head of the Centre for Energy Studies (1995–97) and Principal (1997–98), Visvesvaraya Regional Engineering College, Nagpur. Earlier (1982–83 and 1989), he was a visiting fellow at RMIT, Melbourne, Australia. He obtained his BE, ME and Ph.D. degrees from BITS, Pilani. A fellow of the Institution Engineers (India), Prof. Kothari has published/presented 450 papers in national and inter-national journals/conferences. He has authored/co-authored more than 15 books, including Power System Engineering, Electric Machines, 2/e, Power System Transients, Theory and Problems of Electric Machines, 2/e., and Basic Electrical Engineering. His research interests include power system control, optimisation, reliability and energy conservation.

The author can be contacted at dpk0710@yahoo.com

I J Nagrath is Adjunct Professor, BITS Pilani and retired as Professor of Electrical Engineering and Deputy Director of Birla Institute of Technology and Science, Pilani. He obtained his BE in Electrical Engineering from the University of Rajasthan in 1951 and MS from the University of Wisconsin in 1956. He has co-authored several successful books which include Electric Machines 2/e, Power System Engineering, Signals and Systems andSystems: Modelling and Analysis. He has also published several research papers in prestigious national and international journals.