Determining optimal generator start-up sequence in bulk power system restoration considering uncertainties: A confidence gap decision theory based robust optimization approach

•A novel generator start-up sequence optimization strategy is proposed in this work, taking the integration time of wind-solar hybrid systems into account.•The proposed model requires fewer variables compared with other models, therefore the computational efficiency can be greatly improved.•The confidence gap decision theory based generator start-up sequence strategy is proposed to address the generation uncertainty of wind-solar hybrid systems.•Better generator start-up sequence solutions with higher computational efficiency and less conservatism can be attained by employing the proposed strategy.