ON-LINE APPLICATION OF AN EXTENDED OPTIMAL POWER FLOW ALGORITHM AT A GERMAN SYSTEM CONTROL CENTER

The work presented in this paper deals with a specific aspect referring the operating experiences from the online application of the extended OPF algorithm to the HV and EHV grids. Because of the different structures of the 110kV voltage level compared to 380 and 220kV the OFF algorithm decreases the voltage level of one or several 110kV group to the lower bound during lightload periods. This effect normally does not occur if an OPF algorithm is applied either to the 380kV and 220kV voltage level or exclusively to the 110kV voltage level which is practised usually in the few realized OPF online implementations in power system control centres (e.g. [2], [3]).