Wind Power Plant Short-Circuit Current Contribution for Different Fault and Wind Turbine Topologies

The first generation of utility-sized WTGs were a fixed speed turbine with a squirrel-cage induction generator (SCIG) and is called a Type I generator in wind-related applications. A Type 1 WTG is shown here. Five different types of WTGs were investigated.

An important aspect of wind power plant impact studies is to evaluate the short-circuit current (SCC) contribution of the plant into the transmission network under various fault conditions such as single, two, and three-phase faults in different network locations.

This task can be challenging to protection engineers due to the topology differences between different types of wind turbine generators and conventional generating units. Simulation results for SCC contribution for wind turbine generators obtained through transient simulation are presented. The obtained waveforms are analyzed to explain the behavior -- such as peak values and rate of decay -- of the wind turbine generator.

The effect of turbine and substation transformer winding and grounding configuration on positive, negative, and zero-sequence current and voltage magnitudes is demonstrated. The behavior of fault currents is illustrated by the output of simulations in positive, negative, and zero-sequence components.

Short-circuit current from a Type I WTG.

It is shown that the response of the wind power plant to faults will vary based on the type of the installed wind turbine generators. The SCC will be determined by the generator’s physical characteristics and system transformers configurations. For some wind turbine types, the SCC will also depend on power converter’s control algorithms, which are usually considered proprietary information by the wind turbine manufacturers.

Future plans include conducting similar type of short-circuit current modeling for other types of wind power plants.

This work was done by Vahan Gevorgian and Eduard Muljadi of National Renewable Energy Laboratory.