On-Site Experimental Analysis for Impact of Wideband Terminal Model to Transient Overvoltage Based on a Full-Scale 200kV MMC-HVDC Converter Station

Abstract

This paper investigates the impact of power converter station modeling to high frequency overvoltage based on the on-site experimental test of a fully operational 200 kV MMC-HVDC converter station. Artificial short-circuit faults were generated in the system with hybrid DC circuit breakers along coaxial cables by means of an unmanned aerial vehicle for the first time. Fault transients recorded during the tests are found not to comply with the typical framework where power stations are assumed to present a high impedance, or at least dominated by the reactor inductance. This discrepancy is proven to be caused by parasitic elements at the terminals of the converter station, resulting in a spurious low-frequency resonance dominating fault transients. A wideband converter station model is proposed and validated by the test data. The simulation results show that the proposed wideband model should be adopted avoiding the risk of huge resonance bias in short line distance. When fault distance is 10 km away, converter station model will converge to standard AVM, while the high impedance or reactor model is no longer valid. The experimental data provide a benchmark to validate the converter station model for transient overvoltage or electromagnetic interference under the fault condition.