Short-Circuit Modeling of DFIG-Based WTG in Sequence Domain Considering Various Fault- Ride-Through Requirements and Solutions

Abstract

The doubly fed induction generator (DFIG) based wind turbine generator (WTG) can activate different fault ride through (FRT) control schemes and circuits to comply with various grid code or utility interconnection requirements. These FRT solutions play a key role in the resulting fault current of the DFIG-based WTG as well as the voltages and currents distributed in faulted networks. This paper accounts for their impact by proposing a new generic sequence domain model of the DFIG-based WTG for static short circuit calculations. In this paper, the FRT configurations are classified into three types. The proposed model first calculates the positive- and negative-sequence current phasors under the specified FRT control. Then based on the control, the desired currents and voltages are calculated by explicit equations to determine whether the crowbar could operate during FRT operation. By comparing with detailed electromagnetic transient (EMT) simulations using an EPRI benchmark system, the proposed model, incorporated into an iterative steady state solver, is shown to be accurate to calculate voltage and current phasors in an efficient manner. The proposed model provides a rapid tool for short circuit computations and protective relaying studies considering various grid code requirements and FRT implementations.