procedure and device for the determination of kortslutningseffekten in an electric växelströmskraftnät which is connected to a high-voltage likströmsöverföring

摘要

The invention relates to the determination of short-circuit power (SCC1, SCC2) in an electric power network (N1, N2) for alternating current, which at a connection point (J1, J2) is connected to a converter installation (PL) for transmission of high-voltage direct current. A converter (SR1, SR2) comprised in the converter installation operates with a control angle ( alpha 1, alpha 2). Power values (MQ(t'0)), (MQ(t'k), MQ(t'n)) of reactive power (Q1, Q2) consumed by the converter and voltage values (MU(t'0)), (MU(t'k), MU(t'n)) of the voltage (U1, U2) of the power network, sensed at the connection point, are formed and stored at a first calculating time (t'0) and at least one second calculating time (t'k, t'n). During a measurement interval (t1-t2) which at least partly coincides with the calculating interval (t'0-t'n), the control angle ( alpha 1, alpha 2) of the converter is given a control-angle addition ( DELTA alpha 1, DELTA alpha 2). A power difference ( DELTA Q'k) is formed in dependence on the difference of the respective power values, and a voltage difference ( DELTA U'k) is formed in dependence on the difference of the respective voltage values. A measured value (MSSC1, MSSC2) of the short-circuit power of the power network is formed in dependence on the power difference and the first voltage difference.