Load Rejection Overvoltage Suppression and Parameter Design Method of UHV AC Transmission Line

UHV (ultra-high voltage) by instant AC transmission system is accompanied by huge reactive power transmission. When the load drops sharply, it is easy to produce serious power frequency overvoltage, which is also defined as load rejection overvoltage. This paper makes an in-depth analysis from the perspective of voltage increase caused by instantaneous load unloading, and obtains the causes and key influencing factors of load rejection overvoltage. Taking the UHV AC transmission line of a practical project as an example, the suppression effect of the suppression strategy represented by the installation of opening resistance and shunt reactor on the load rejection overvoltage is analyzed. The simulation results show that the above method has an obvious inhibitory effect on load rejection overvoltage. Based on the optimal suppression principle, the optional interval range of the opening resistance and shunt reactor parameters are designed.