Research On Transmission System Expansion Planning Model Considering Short Circuit Current Constraint

With the increas ing load demand of the power system, the scale of the power grid becomes larger and larger, leading to the enhancement of short circuit current level and affecting the security and stability of power system operation. The short circuit current level is closely relevant with the structure of the power grid. However, the traditional transmission system planning usually verifies the short circuit current level after new power grid structure is determined, ignoring the important role of short circuit current on power system planning and the possible applications of the short circuit limiting measure. Hence, it is meaningful to do research on how to coordinate transmission system planning with applications of the short circuit limiting measure and balance the transmission network capacity with short circuit current capacity. Based on the background above, the feasibility and reasonableness of the transmission system expansion planning considering the short circuit current constraint is discussed and the main work finished in this dissertation is as follows.Firstly, the current status of research on transmission system planning, application of the short circuit limiting measure and short circuit current calculation standard are detailed in this dissertation.Secondly, an optimal configuration model of typical power system short circuit current limiting measure aiming at minimization in total cost of the short circuit current limiting measures is proposed, and the power flow balance constraint, bus voltage constraint, transmission line capacity constraint, short circuit limiting measure application constraint are considered. To improve computational effic iency, the improved discrete particle swarm algorithm based on selecting strategy is devised.Thirdly, the typical short circuit current limiting measure is added to the traditional transmission system planning based on bi-level programming. The bi-level model of transmission system expansion planning considering opening lines for reducing short circuit current and the bi-level model of transmission system expansion planning considering optimal configuration of current limiting reactor are proposed. The adaptive genetic algorithm and improved discrete partic le swarm algorithm are used in solution of the upper and lower model respectively.Finally, the New England 39-bus test system, the garver 6-bus test system, the 18-bus test system and the 19-bus test system based on 18-bus test system verify the feas ibility and reasonableness of the model proposed above respectively.