| 摘要 |
<p>Subject of the invention is a procedure for continuous identification of the distance between the load node and the voltage instability within the power supply system. The procedure is based on series of measured or calculated phasors of local voltage and load current of the node. The measured phasors are provided by phasor measuring devices, located in the network nodes, while the calculated phasors are the result of running a software, which is used in control centres for estimating situations within the power distribution system. The basic criteria for continuous identification of the distance between the load node and the voltage instability within a power supply system is the comparison of the Thevenin equivalent of the power distribution system regarded from the individual load node and virtual load impedance. By this new procedure the Thevenin equivalents can be determined only from two subsequent situations within a power distribution network, which represent the initial and Tellegen associated network. The procedure can be applied in the load node, a numerical relay or control centre by a special software for continuous identification and preventing any voltage instability of the power distribution network. If the procedure establishes a critical distance to the voltage instability, it triggers automatic protective measures according to the corresponding logic.</p> |
