Asymmetric short-circuit current calculation method and system for large-scale new energy station

Abstract

The invention provides an asymmetric short-circuit current calculation method and system for a large-scale new energy station. The method comprises the following steps: judging a fault type and a fault phase; the negative sequence impedance of each new energy station is calculated, and the positive sequence initial voltage of each new energy station is calculated; calculating the output short-circuit current of each new energy station; according to the fault composite sequence network, a simplified equivalent circuit is obtained through circuit simplification; calculating the positive sequence voltage of each new energy station; comparing the positive sequence voltage and the positive sequence initial voltage of each new energy station, judging whether a voltage difference value meets convergence precision or not, and solving negative sequence current and zero sequence current output by each new energy station according to a circuit equation; and outputting the output phase current of each new energy station. According to the method, the influence of converter control on a phase selection element is overcome, the number of iterations can be effectively shortened, the process of solving matrix inverse operation by a node voltage method is avoided, and the method has relatively good engineering practicability and precision and can be suitable for a large-scale new energy field station.

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