A Comparative Study on Methods of Connecting Large-Scale Offshore Wind Farms into Power Systems

Abstract

The paper uses PSS/E software to study connecting an offshore wind farm with 864 MW into the 2015 Taiwan power system. Major simulation works include: steady-state power flow, fault current computation, transient stability analysis and the impact analysis on critical fault clearing time. Three connection methods, i.e., single-point, separatepoint and multi-point connection, are proposed, in which the single-point connection is divided into two voltage levels (161kV and 345kV). During the steady-state operation, simulation results indicate that the 345 kV single-point connection method demonstrates the best performance. In addition, the fault current from a wind farm is partially determined by its connection location. In terms of transient stability, when grid faults take place, the 161kV singlepoint connection method appears to report the smallest voltage drop as compared to other connection scenarios. Its amplitude of frequency disturbance, however, is the greatest of all connection scenarios. As for the analysis on critical fault clearing time, simulation results indicate that the critical fault clearing time in all connection cases is approximately two times greater than that required by the Taipower standard. Simulation results in this study can be expected to provide valuable guidelines for connecting offshore wind farms into the power systems in the future.