Optimal Scheduling of Active/Reactive Power for Inverter Interfaced Distributed Generators during Voltage Sags

With the growing penetration of inverter-interfaced distributed generators (IIDGs), the fault ride- through (FRT) and the voltage support capability are emphasized by grid codes for stable and secure operation. To achieve economic operation considering voltage support process, this paper proposes an optimal scheduling scheme through balancing injected power and load supply power during fault periods. In the proposed optimal model, the total required injected power for voltage support is evaluated firstly. And then the power sharing scheme among IIDGs is formulated according to the operation costs and dispatchable capacity. To achieve voltage support and economic operation, the optimal scheduling strategy for active/reactive power is proposed, which is executed through rewarding voltage support power provision and punishing load supply power curtailments. The piecewise linearization method is deployed to linearize the nonlinear issues introduced by converter constraints. The proposed method is fully tested, and the results demonstrate that 15.42% of annual costs can be reduced compared with existing methods.