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Due to the renewable generation target and the continuously increasing electrical demand, a large number of wind farms and solar photovoltaic (PV)plants are being planned in China. As the electricity fault characteristics of inverter-interfaced renewable energy sources are different from the traditional synchronous generators. The fault circuit contributions are getting more and more attention from engineers. In this paper, the short-circuit calculation method considering dynamic reactive power support of renewable energy systems is proposed. Through a large number of calculations, the factors affecting short-circuit currents and trends of short-circuit current under different voltage drop depths are discussed. The results presented by this paper provide the reference for future research on control and protection of power systems with high penetration of renewable energies.

Due to wind power forecasting error, active power control may not satisfy the control objective. By analysis, the main reason is the asymmetry of power forecasting error. For this, an active power control strategy considering the asymmetry of wind power forecasting error is proposed. Using historical data, wind power forecasting error and its confidence interval are estimated. And confidence interval of wind power forecasting is introduced to establish the optimization model for dispatching active power among wind farms. Then the asymmetry power forecasting error can be compensated by the model. Based on this, operation risk is introduced to optimize the power distribution strategy. Then a simulation is designed using actual data of one wind power base in China. The results show that the proposed strategy is reasonable and effective to improve the performance of active power control of wind power and reduce the risk of power shortage.