Transient short-circuit currents analysis of renewable energy sources considering multiple controller working stages

The study of transient short-circuit current of renewable energy sources (RESs) can provide important evidence for the design principles and setting calculations of protection relays. However, existing transient short-circuit current calculation models for RESs fail to accurately characterize the response features of the controller under different working stages. For full-power inverter-interfaced RESs, this paper adopts the method of best square linear approximation to linearize the active powe r of photovoltaic, solves the fault component of the photovoltaic DC bus voltage. And then obtains a transient short-circuit current calculation model based on the power variation under the constant power control stage and the amplitude limitation control stage. For partial-power inverter-interfaced RESs, this paper simultaneously considers the rotor side converter control stage and the Crowbar control stage, proposes a transient short-circuit current calculation method based on the superposition of multiple responses, and achieves a unified expression of short-circuit currents at different control stages while ensuring local differences. Finally, a test system is built on the PSCAD/EMTDC, which demonstrates the feasibility and correctness of the proposed method.