METHOD OF DETERMINING THE SHORT-CIRCUIT IMPEDANCE OF AN ELECTRICAL POWER SUPPLY SYSTEM TO BE MONITORED

摘要

2091345 9204635 PCTABS00011 In a process for finding the short-circuit impedance of an electric power supply system to be monitored, coefficients of a system matrix Xi or a system matrix Xu1 of a preselected model of an electric power supply system is calculated taking account of the mains frequency of the system to be monitored and the preselected time sequence of scanned values of a measurement value proportional to the current and voltage in the system. Starting with preselected parameter vectors .beta.i(O) or .beta.u1(O), error vectors at a predetermined smallest error vector are found with the actual scanned values of the measurements and the actual system matrix Xi or Xu1 by recursive estimation and the short-circuit impedance is determined therefrom. In order to avoid errors through the effect of an arc in finding the short-circuit impedance, in the process of the invention the system matrix Xu1 is calculated by including and taking account of the actual sign of the scanned value (yi(k)) of one measurement; in addition, an additional component taking account of a short circuit arc is included in calculating the parameter vector .beta.u1.