Flexible Transmission System Expansion Under Uncertainties

There are numerous uncertainties in the process of power grid planning subject to uncertain factors in national policy, economic development, and environmental changes in the future. In an uncertain environment, the traditional network planning methods are inadequate as follows:â‘ Certain data required for traditional network planning model is extremely difficult to forecast;â‘¡Traditional network planning models can not account large number of uncertain factors, only reflecting a few uncertain scenes;â‘¢Traditional network planning model can not account the uncertainties brought about by market-oriented reforms;â‘£The traditional network planning program can not reflect its adaptation extent to the uncertainties.This thesis mainly focus on three uncertain factors which come from the load growth, generator capacity and line faults, and many other objects to meet in power grid planer's job, study the flexible network planning methods considering uncertain factors, define various planning program evaluation index, establishes flexible programming models meeting different indicators and finally gives the solution method based on greedy random adaptive search algorithm. First, uncertainty mathematical programming theory is introduced into network planning and the major uncertainties are descried and simulated with random variables. On the basis of this,the flexible network planning modal based on chance constrained programming, flexible network planning model considering probabilistic available transfer capability and flexible network planning modal considering pessimistic minimum load shedding cost are established from line overloading probability, the probabilistic transfer capacity and the pessimistic minimum load-shedding cost stand of view respectively. Using greedy random adaptive search algorithm for solving the model.Calculation results show that the obtained planning scheme comes out of models in this paper have better adaption to the uncertainties than the actual grid. Finally, the studied theory is applied to a China regional power grid 500kV networks planning in 2012, and obtains the planning schemes adapt to future uncertainties.