RESEARCH ON DE-EXCITATION PROJECTS FOR POWER GENERATING SETS IN THREE GORGES HYDROELECTRIC POWER STATION

Three kinds of de-excitation projects, i.e., linear resistor, ZnO non-linear resistor and SiC non-linear resistor, which may be chosen for power generating sets in ThreeGorges Hydropower Station are discussed. The de-excitation situation of the three projects under heavy field current and low field current are compared by simulation, and the de-excitation situation of hydroelectric sets in Three Gorges Hydropower Station by two kinds of non-linear resistor are emphatically researched. The research shows that when de-excitation iscarried out by linear resistor, the least time for de-excitation is 15 seconds or longer, thus, the generating sets cannot beprotected; when non-linear resistors are used in de-excitation for same generating sets, the time for de-excitation is 2-seconds, therefore, the non-linear resistors are suitable to the de-excitation system for hydroelectric sets in Three GorgesHydropower Station and it is suggested to apply SiC non-linear resistor de-excitation system to the firstling generating sets of Three Gorges Hydropower Station.