Spinning reserve and under-frequency load shedding strategies for the interconnected China Light power system

Following the interconnection of the China Light & Power (CLP) and Hongkong Electric Co. (HEC) power systems in the early 1980s, the two companies have benefited not only from the sharing of spinning reserve and interchanges of economy energy, but also from the mutual support during generation contingencies. Concerted efforts have been taken in CLP to design optimised under-frequency strategies (in terms of spinning reserve and load shedding) so as to minimise both the level of spinning reserve requirement and the amount of load shedding. Particular emphasis has been placed on taking full advantage of the interconnection operation and on enhancing both the scheme security and reliability. The author presents the various considerations given in the design of the under-frequency strategies