Research scheme of self-excitation over-voltage in UHV long transmission lines

Self over-voltage and operating over-voltage, caused by load shedding, may also occur at the same time in ultra-high voltage(UHV) long lines. Both were Superimposed on each other resulting in a great danger over-voltage. Transmission lines, transmission equipments and insulation of large generators will be seriously damaged by the over-voltage, especially large generators spindle will be twisted causing immeasurable losses. In this paper, based on 1000kV UHV long distance single and double circuit transmission lines, research ideas and suppression scheme for self over-voltage and operating over-voltage were proposed. First, causes and mechanisms which cause generator self over-voltage need in-depth be studied; Producting conditions and location, development process of self over-voltage need be accurately analysed; When self over-voltage and operating over-voltage occur simultaneously caused by load shedding, overvoltage peak and process need be studied; Study technology of control and parameter setting of arrester to effectively restrained self over-voltage and operating over-voltage; The same time, study how protection, reclosing, and other secondary equipment have an effect on operating over-voltage and self-excitation; Ultimately over-voltage integrated control system will be constructed from control devices such as protection reclosing, Etc. and various over-voltage suppression measures. In this paper, the proposed study scheme has important theory significance and economic benefits to ensure safety of future UHV grid and large generators.