METHOD FOR ESTIMATING EQUIVALENT IMPEDANCE OF POWER SYSTEM AND METHOD AND APPARATUS FOR DETECTING INDIVIDUAL OPERATION OF DISTRIBUTED POWER SOURCE

摘要

PROBLEM TO BE SOLVED: To sense individual operation of a distributed power source by measuring output voltage and current of the distributed power source and estimation-calculating line resistance and line reactance which minimize difference between a terminal voltage estimated value calculated from the above values and a measured voltage value. ;SOLUTION: Output current I_gti and voltage E_ti of a distributed power source G is measured and supplied to a parameter estimation-calculation part 12. The calculation part 12 estimates the most likely values of main system supply voltage E_s, line resistance R and line reactance by the minimum square method for example. A parameter reference setting device 13 stores set values such as standard values for main system supply voltage E_s, line resistance R and line reactance viewed from an output end during normal interlocked operation of the distributed power source G and deviation amounts required for determining abnormality. The main system supply voltage, line resistance and line reactance estimated in the calculation part 12 are supplied to an abnormality detection part 14, which compares these values with reference values, wherein when deviation values are more than expected values, abnormality is detected, an abnormal signal is supplied to an individual operation detecting part 15 for issuing a signal representing individual operation.;COPYRIGHT: (C)1997,JPO