METHOD FOR COMPUTER-AIDED ASCERTAINMENT OF THE IMPEDANCE OF AN ELECTRICAL ENERGY NETWORK

摘要

The invention relates to a method for the computer-aided ascertainment of the impedance of an electrical energy network (EN), wherein the electrical voltage (VPCC), the active power (PPCc) and the reactive power (QPCC) are measured at a connection point (PCC), by which an electrical energy production installation is connected to the energy network (EN), at respective successive instants. In this case, the impedance value (ZGE) is estimated at respective present instants by means of a computation code that is independent of the phase of the measured voltage (VPCC). The estimation is carried out only for relatively large variations in the measured voltage or reactive power. The estimate is also taken into account only if its estimate error is small. The invention is based on the insight that accurate estimation of the impedance is possible at particular operating points of the energy network even without knowledge of voltage phase. The method according to the invention is used particularly in an energy network to which a wind turbine or a wind farm comprising multiple wind turbines is connected.