Modal analysis of Type-1 wind farm connected to series compensated transmission line and LCC HVDC transmission line

This papers presents a comprehensive analysis of the potential of sub-synchronous resonance (SSR) in Type-1 wind farms connected to Line Commutated Converter (LCC) based HVDC transmission line. Since series compensated lines are also known to cause induction generator effect SSR in Type 1 wind turbine generators, this paper also considers a series compensated line in parallel with the HVDC line for the investigation of potential SSR. CIGRE Benchmark HVDC system and IEEE First Benchmark system are considered as the study system components. A dynamic model of the study system is developed and linearized at several operating points for eigenvalue analysis of the potential of SSR. A sensitivity study of the SSR modes with respective to variation in different model parameter such as rectifier firing angle, DC line power flow, series compensation level is also reported. It is found that HVDC rectifier station current regulator does not interact with any sub-synchronous modes of the wind turbine generator. Hence, the operation of a Type-1 wind farm connected to series compensated line and HVDC line is may not be subject to SSR issues. However, when the wind farm operates radially with the series compensated line, it may experience SSR oscillation due to induction generator effect.