Coll. of Water Conservancy and Hydropower Engineering;
Hohai Univ.;
Nanjing 210098;
P. R. China;
Research & Development Center;
Nari-relays Electric Ltd;
Nanjing 211106;
P. R. China;
Dept. of Control Science and Engineering;
Huazhong Univ. of Science and Technology;
Wuhan 430074;
P. R. China;