Optimal Transmission Switching Based On Probabilistic Load Flow For Power System With Large Scale Renewable Energy Integration

High scale integration of renewable energies has led power system towards a new set of challenges that have increased the complexity of cost optimization problems.Moreover,forecast errors in the prediction of wind,PV and load greatly affect the accuracy of optimization.Previous studies have been focused by using optimal transmission switching(OTS)to solve different power system problems.As renewable sources integration in the power system imposes the uncertainties which change the system state dynamically,and to apply OTS under such conditions is a big challenge.To cater with the above mentioned problem we used probabilistic load flow(PLF)with Gram-Charlier expansion method,to calculate the uncertain condition of the power system and the state of the power flow.Therefore,Gram-Charlier method has been proposed for solving PLF based OTS for large-scale integration of renewable energy.The Gram-Charlier Expansion method has been used for forecast error evaluation in order to improve the accuracy of the proposed method.Furthermore,proposed method use in this work has the fast convergence properties.In this work,uncertainies of a wind farm along with PV and load are considered as in realistic aspect.In this thesis,the simultaneous optimization of generation dispatch and network topology for PLF based OTS has been investigated.The results evaluations are based on the 24 hours with varying topology structure and cost reduction.With the different time scales,different level of penetration of RES is considered to verify the model effectiveness and system behavior.For justification and benchmarking of the proposed model modified IEEE-118 bus system is used.Using proposed formulation,uncertainties of the renewable sources can be taken into account to deal with the dynamic behavior of the system.The results depict that the proposed approach is quite useful for large-scale power systems.The introduction of new technologies to create a more controllable and flexible grid is a part of the smart grid concept and essential to its success.Presently,full control of transmission assets is not incorporated into models for optimizing electrical energy dispatch.OTS is a simple and effective way of taking advantage of grid controllability making better use of the existing system and meeting growing demand with existing infrastructure.