Under Frequency and Under Voltage Load Shedding Criterion for High-Penetration New Energy power System

As the third line of defense equipment to prevent the frequency collapse of the power system, with the wide access of renewable energy, the under frequency and under voltage automatic load shedding device has the risk of miss and mal operation due to the change of power grid characteristics. Firstly, this paper aims at the risk points of incorrect tripping of the power reverse transmission line, the failure of the device due to excessive RoCoF and voltage suspension under fault, On the basis of combing the existing criteria, the causes of incorrect action of the device are analyzed, A comprehensive improved criteria is proposed for judging allowable cut state by multi-path acquisition line load, the RoCoF unlocking condition and the under voltage special wheel unlocking condition. Finally, the validity of the proposed criterion is verified by simulation test.