A Closed Loop Load Control Scheme for Stabilizing Frequency in Power System with Block Events

The emergency frequency control of high-voltage direct-current (HVDC) receiving-end grid is investigated in this paper. While the multi HVDC feed-in system has several potential frequency stability problems, this paper mainly focuses on the worst scenario: frequency decreases on account of DC system blocking. A novel closed loop load control scheme based on the demand side control and wide-area measurement system (WAMS) is proposed. By deriving the power-to-voltage characteristics, the potential contribution to frequency management of industrial intensive load and static ZIP load is investigated at first. Then a multi-voltage level coordinate scheme is established with the help of wide-area measurement system (WAMS), which aims to maintain frequency stability when serious faults occur in the power system. The effectiveness and robustness of proposed scheme is validated through simulation on real-time digital simulator (RTDS) platform. An actual accident is taken as study case. Results indicate that the proposed scheme could provide remarkable improvement in both security and economic aspects.