STABILIZER FOR ELECTRIC POWER SYSTEM

PROBLEM TO BE SOLVED: To stabilize the system without excessively blocking generators, even if a stabilizer is applied to a local system which has short reclosing time. SOLUTION: The stabilizer for electric power systems operates as follows: based on the number of generators in operation and their outputs, before and after the occurrence of an accident in a transmission line in proximity with a generator group, where step-out of the electric power system is predicted and the measured values of bus voltage in proximity to the generators and generator currents, the phase angle fluctuation of the generator group, after the accident is removed is computed; the phase angle fluctuations of the generator group a short time ahead is computed with estimate; and if step-out of the generator group is forecasted based on the result of the computation, a part of the generators are blocked. The stabilizer is provided with a reclosing stabilization evaluating means 9, which is fed with an estimated value of the phase angle fluctuations of the generator group in the estimated reclosing time of the faulty transmission line, the total output of the generator group before the occurrence of the accident, the driving point reactance value after reclosing when the electric power system is viewed from the bus in proximity to the generators, and parameters including preset generator constants, and decides as being after reclosing if the electric power system is judged as unstable, the generators are blocked. COPYRIGHT: (C)2005,JPO&NCIPI