Based on the analysis of the operating over-voltage of mine power system, the parameter identificationmethod for operating over-voltage is presented and the identification model is given.

It emphatically anaylses advantages and shortcomings of several types of popular protection instruments of over-voltage, and advances the protection methods of vacuum circuit breaker′s operating over-voltage.

To offer the basis for revising national standard GB 50227—1995“Design specification of shunt capacitor installation”, the research on three special subjects, harmonic suppression countermeasures, operating over-voltage protection, capacitor and capacitor bank protection, was carried out.

Analyses of the transient process ab out the the switching overvoltage generated by the open-phase no-load transform er cut by the 10kV vacuum load switch;

Adopting line surge arresters to suppress switching overvoltages in 750 kV EHV transmission lines;

Idea of increasing only one group of arrester installed along line replacing with parallel resistance in breakers to suppress switching overvoltage in 750 kV transmission line is realized in this paper.

Field-circuit Analysis of Switching Over-voltage for Power Stations;

Study of new method for on-line safety monitoring in motor switching over-voltage;

Effect of neutral grounded by low reactance to the switching over-voltage for Gongboxia transformer;

The paper describes the harm of the operating over voltage to high-voltage motor in terms of the operating over voltage mechanism.

The paper elaborated the common over voltage type in medium voltage power network-the forming reason and developing mechanism for operating over voltage and ferro-resonance over voltage, and some kinds of effective solving scheme were presented.