Transient Stability Analysis of a Grid-Integrated Wind Farm Under Fault Condition at the Point of Common Coupling

Abstract

This paper presents an overview of transient analysis carried out to analyze the behaviour of network integrated wind farm under a three-phase fault at the point of common coupling (PCC). A wind farm with a capacity of 20MW is modelled and integrated into the IEEE 9-Bus test network. A three-phase fault is applied at PCC for 100ms. During a three-phase fault, the PCC bus experiences voltage dips as low as zero volts and the wind farm plant is configured to supply reactive power to hold on to the grid voltage without exceeding converter rating of the plant. The network synchronous generators will also experience voltage dips up to 80% or lower of nominal voltage but this voltage dips will not trip the generators for durations lower than 1 minutes. Likewise, network frequency fluctuation will not warranty tripping of the synchronous generators for this short period according to International Electrotechnical Commission (IEC61400-1) standard for wind energy. The wind turbines can ride through low voltages while remaining connected to the network during fault periods. In the results section, the effect of the fault on the network voltages, network frequency, the active and reactive power and currents at the network buses, PCC and at the wind turbine buses are all discussed. DIgSILENT Powerfactory was used for modelling and simulation of the network connected wind farm and the transient response.