Research On Optimization Method Of Network Reconfiguration Considering Uncertain Factors

With the development of electric power industry, the interconnected power gridincluding the nation’s major regional power grid is basically formed. The study ofblack-start restoration after large scale blackout is very important. Networkreconfiguration is the main task of grid system recovery. Building the backbone networkquickly and efficiently can speed up the recovery process and reduce power loss.Network reconfiguration involves a lot of complex primary and secondary equipment putinto operation, along which the system will face a variety of uncertain factors that couldcause the system recovery failure. Considering the uncertain factors, this paper presentstwo optimal control strategies. One is modeling of these factors in order to study itsimpact on the recovery process, the other is improving the ability of the system to dealwith unexpected situations.Due to the reality of a lot of equipment put into operation, a model with operation ofgeneration and translation line that affect the recovery process following the massiveoutage is obtained in this paper. The effect of downtime of the generation unit, therecovery time and the rated capacity on recovery process is solved. Further the switchingon of transmission lines is equivalent to the operation of transformer substations, withwhich the method to calculate the weights of branches is proposed. And on the basis, thepaper gets optimization method with small risk and high reliability.Considering the effect of uncertain factors, optimization method ofchance-constrained programming for network reconfiguration is present in this paper.First, the failure rate of the line putting into operation is calculated by Monte CarloSimulation, which is the constraints condition of opportunity in the model. Based on thispoint, the lines which don’t satisfy condition can’t be selected, so the optimizationmethod can realize the balance between effective capacity and reliability of devices.Due to the risk of uncertain factors, the method of improving the capacity to dealwith accidental situation is put forward. Considering the voltage fluctuation when thedevices are putting into operation, the target of ensuring voltage security is determined.By the control of generation output, the system can reduce the failure possibility ofoperation because of voltage fluctuation.The effectiveness of the proposed method considering uncertain factors duringnetwork reconfiguration is verified by simulation results of New England39-bus systemand30-bus system.