METHOD AND APPARATUS FOR SUPPRESSING RESONANCE PHENOMENA IN THE A-C NETWORK ON THE INVERTER SIDE OF A HIGH VOLTAGE D-C TRANSMISSION SYSTEM

摘要

ABSTRACT OF THE DISCLOSUREIf in a high-voltage d-c transmission system(HVDCTS), a resonance frequency of an a-c voltage network (NB)connected to the inverter (1B) is located in the vicinity of avoltage component contained in the a-c voltage network, aresonance frequency which often cannot be compensated by acurrent regulator controlling the rectifier stage (1A) iscoupled into the d-c circuit of the HVDCTS via the inverter.Therefore, resonance phenomena which requires an emergencyshutdown of the HVDCTS are generated. Therefore, a pilotquantity (U'd) is formed with a defined phase shift relativeto the resonance oscillation of the HVDCTS voltage and addedto the output of the current regulator. Thereby, a constantHVDCTS current can be generated for a given operating pointand the resonance in the a-c voltage network (NB) can bedamped. If the resonance oscillation is determined by twoquantities (U'd, i'd) of, respectively, the HVDCTS voltage aswell as of the HVDCTS current, stable damping of the resonancephenomena can be achieved by the pilot control described withthe two quantities even for deviating operating points.