1. Key Laboratory of Power System Intelligent Dispatch and Control of Ministry of Education(Shandong University), Jinan 250061, China; 2. NARI Group Corporation(State Grid Electric Power Research Institute), Nanjing 211106, China; 3. Electric Power Research Institute of State Grid Sichuan Electric Power Company, Chengdu 610072, China

In view of the under-frequency control problems of receiving-end power grid subjected to blocking faults of line-commutated converter-based high-voltage direct current(LCC-HVDC), a feature-driven scheme of emergency load shedding is proposed by taking into account the regular response pattern after the faults occur. The changing rule of frequency and voltage at the instant of LCC-HVDC blocking fault is derived, and the low-frequency and high-voltage feature caused by time-delay inter-tripping of reactive power compensation devices is analyzed. Moreover, the partial voltage characteristics are extracted by grey correlation analysis, and the initial changing rate of frequency is used to match the action scheme by k-nearest neighbor algorithm. On the basis of the traditional under-frequency load shedding scheme, an emergency load shedding stage is added to deal with the LCC-HVDC blocking fault, and the local-monitored low-frequency and high-voltage feature is used as the operation criterion, and is adopted to match the decision table in real time to cut off the load of fault areas. Finally, a provincial power grid is taken as a case to validate the effectiveness of the proposed scheme.