PROPOSED 4 GW RUSSIA-GERMANY LINK - IMPACT OF 1 GW INVERTER STATION ON TORSIONAL STRESSING OF GENERATORS IN POLAND

The European power systems are in the process of a new orientation whi ch will facilitate and promote exchange of electric pou er between Eas tern and Western European nations. One such example is the 4 GW HVDC l ink from Russia to Germany where a 1 GW converter station has been pro posed for central Poland. This paper considers the impact of the propo sed 4 GW Russia Germany HVDC link on the Polish Grid Network and possi ble excitation of torsional vibrations in shafts of steam turbine-gene rator-exciter units connected to the system by non-characteristic curr ents due to the link. Excitation of torsional vibrations in machine sh afts due to modulating currents and the level of risk of damage to mac hine shafts due to subsynchronous currents injected into the network b y the inverter is assessed. Dynamic parameters of system loads and the power factor of loads which influence system scaling factors are also discussed. The paper also examines the most probable location of the proposed 1000MW converter on the Polish Grid Network. System scaling f actors are evaluated for different system configurations for each gene rator at risk and generators most at risk are identified. The paper th en investigates transient behaviour of the Polish power system followi ng loss of the proposed link at full import. Transient stability perfo rmance is also evaluated for a range of system faults of different fau lt durations, distances, and locations from power plants.