Power Flow Calculation Of Microgrid Based On Generalized Tellegen Theorem

In the background of the world energy crisis and environmental pollution,microgrid as a useful supplement to power grid,which can solve the absorption problem of new energy.As a basic tool of microgrid analysis,power flow calculation is indispensable in the process of fault analysis,planning,design and protection setting of microgrid.Therefore,the research on power flow algorithm of microgrid has practical significance and application value.Aiming at the power flow calculation of microgrid,this thesis establishes a power flow calculation model of microgrid based on the structure characteristics of microgrid,the overall control strategy of microgrid and the control modes of different distributed generations.In order to improve the accuracy of power flow calculation in microgrid,a method of dealing with distributed power device nodes is presented.This method fully considers the static characteristics of distributed power sources.Under the peer-to-peer control strategy,all distributed power sources adopt droop control mode.By analyzing the power-frequency characteristics of distributed power sources,distributed power device nodes are divided into three categories: PQ,PV and droop.Which are used to establish the power flow calculation model of microgrid under various nodes of microgrid.In order to improve the speed of microgrid power flow calculation method,based on the traditional Newton power flow method and combined with the generalized Tellegen theorem,a microgrid power flow algorithm based on the generalized Tellegen theorem is proposed.The algorithm only forms a Jacobian matrix in the process of power flow calculation of microgrid.On this basis,combined with the advantages of simplicity and rapidity of the adjoint network equation obtained by generalized Tellegen theorem,the modified equation of the new power flow algorithm of microgrid is obtained,and the concrete steps of power flow calculation of microgrid are given,which greatly reduces the workload of power flow calculation and thus reduces the power flow calculation.The whole time used improves the calculation speed.The algorithm is simulated on the platform of Matlab software.The algorithm is applied to the low-voltage microgrid for power flow calculation.The results of power flow calculation are compared with those of traditional power flow algorithm,which verifies the accuracy and rapidity of the proposed power flow algorithm.