1.State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources (North China Electric Power University), Beijing 102206, China;2.State Key Laboratory of Advanced Electromagnetic Engineering and Technology (Huazhong University of Science and Technology), Wuhan 430074, China;3.Beijing Sifang Automation Co., Ltd., Beijing 100085, China;4.Power Dispatch and Control Center of China Southern Power Grid, Guangzhou 510530, China

With the rapid development of renewable energy, it is transforming from auxiliary power supply to main power supply.There are two problems in the calculation of short-circuit current in the existing renewable energy projects. Firstly, the fault characteristics of renewable energy are characterized by 1.2 to 2 times of rated current, which leads to poor calculation accuracy and is difficult to meet the protection requirements. Secondly, the existing short-circuit current setting calculation software does not support iteration, so it is unable to update the fault current of renewable energy according to the change of node voltage, and reflects the characteristics of voltage controlled current source. To solve this problem, based on the refined analytical model of fault characteristics of renewable energy, combined with the field fault recording data, the voltage-current mapping relationship is constructed to meet the requirements of practical engineering calculation. Then, the fault area is divided according to the degree of node voltage drop and the connection relationship between nodes after the power grid fault, and the local iteration calculation is carried out according to the practical calculation formula of renewable energy in the fault area to solve the node voltage and short-circuit current of the network, so as to avoid the convergence problem caused by the global iteration and shorten the calculation time. Finally, the calculation effect of the proposed method is verified by engineering calculation software.