Study Of Comprehensive Evaluation Of Breaking Up Electromagnetic Loop Network

Due to the rapid growth of the demand for electricity consumption,it is often difficult for the current voltage level transmission lines to meet the demand of the transmission capacity,need to build a higher voltage level transmission lines.In the early stage of high voltage line construction,in order to ensure the normal power supply and reliability,high and low voltage level transmission lines are often operated in parallel through transformer,which forms a high and low voltage electromagnetic loop network.When the high-voltage transmission network construction is relatively mature,the existence of electromagnetic loop network will bring a series of drawbacks to the safe and stable operation of power grid.For example:increase the short-circuit current level of the system;the fault of high voltage transmission line will cause massive power transfer,which probably lead to thermal stability and dynamic stability failure;it will make the distribution of power flow unreasonable,increase the network loss,and is not conducive to economic operation;increasing the complexity of the automatic safety device of the power grid,which may lead to further expansion of the accident.Therefore,at the right time,it is necessary to solve the electromagnetic loop network,to achieve the hierarchical operation and partition running of power grid.This paper improved the particle swarm algorithm,the chaotic map was introduced in the initialization of particle swarm,inertia weight adaptive adjustment was adopted,what's more,the global optimal selection pool and the global optimal were proposed in the process of obtaining the global optimal solution.The multi-objective optimization model was established,which has the least network loss,the largest power supply capacity and the largest partition,the improved particle swarm optimization was used to wage the optimization calculation,thus,realizing the selection of the alternative solution of electromagnetic loop network in Hubei power grid.Then,combined with the basic principles of breaking up the electromagnetic loop,the evaluation index system of schedule of opening the loop was established,including static safety index,short-circuit current level index,static voltage stability level index,N-1 index,economic index and so on.The weight of each index was given by the combination of subjective and objective weights.Finally,using the method of grey comprehensive evaluation to carries out the comprehensive evaluation of the alternative solution of opening the loop in Hubei power grid,and selected the optimal solution of the electromagnetic loop.