A New Quantitative Analysis Method for Overvoltage in Sending End Electric Power System with UHVDC

With the development of renewable electric power generation and ultra-high voltage direct current (UHVDC) transmission, the transient overvoltage in the sending end electric power system with UHVDC occurs, but it is lack of quantitative transient voltage assessment index (TVAI) to assess the overvoltage. To deal with the above problems, this paper proposes a new quantitative transient voltage assessment index considering overvoltage and voltage dip in the sending end electric power system with UHVDC, and applies it to analyze different influencing factors of overvoltage and determine the dynamic reactive power compensation capacity. In detail, first, according to the principle of the transient voltage assessment index considering voltage dip and the overvoltage assessment index for the distribution network, a new transient voltage assessment index considering transient overvoltage in the sending end electric power system with UHVDC is proposed with the approximated step function. Then, based on the requirements of the system with UHVDC, the parameters of the proposed transient voltage assessment index are determined. Furthermore, with the absolute and relative sensitivity, the impact of the parameters of voltage dependent current order limiter and current control amplifier on the transient overvoltage is analyzed and compared quantitatively. Finally, the impact of reactive power compensation equipment, such as synchronous condenser, static var compensator, and static var generator, on the transient overvoltage of the system with UHVDC is compared quantitatively, and the reactive compensation capacity needed to maintain transient voltage security and stability is estimated. The two applications show the effectiveness and advantages of the proposed index in the sending end electric power system with UHVDC.