利用Teager能量算子瞬时能量的模块化多电平换流器多端柔性直流电网保护方法

To improve the ability of quick clearing and isolating faults of modular multi-level converter (MMC) multi-terminal flexible DC grid, a new pilot protection method with instantaneous energy of voltage fault component extracted by Teager energy operator is proposed. According to the difference of the instantaneous energy of the voltage fault component in the multi-terminal flexible grid with a fault, the protection method chooses Teager energy operator to process the voltage fault component to obtain the maximum instantaneous energy of voltage fault component, then establishes the protection criterion by the maximum instantaneous energy of the voltage fault component, and gives the setting principle. The fault interval and the internal and external faults are determined by the maximum value of the instantaneous energy of the fault component at each protection measurement device, unipolar or bipolar fault is distinguished by the ratio of positive and negative pole fault components' instantaneous energy of converter station on the same side for fault pole seletion. A ±500 kV four-terminal flexible DC power grid model is constructed to verify the protection algorithm on PSCAD/EMTDC. Simulation shows that the proposed protection method can operate quickly and reliably within 3 ms, has strong capacity to resist transition resistance, and can accurately identify the fault interval, distinguish between internal and external faults, implement fault pole selection under different conditions.