Research On Capacitor Optimization Configuration Of Distribution Network Based On Resonance Elimination

As an economical and stable reactive power compensation device,capacitors have been widely used in power transmission and distribution networks to improve the transmission capacity,adjust bus voltage and reduce transmission losses.The load in the power system is generally an inductive load,and its interaction with the capacitive reactive compensation capacitor causes the risk of harmonic resonance in the power grid;Meanwhile,due to the large number of applications of power electronic power conversion devices,the proportion of nonlinear loads in the distribution network is significantly larger than before,which makes the distribution network contain a large number of harmonics;Therefore,harmonic resonance is inevitable in the optimal allocation of reactive compensation capacitors in distribution network.In this thesis,an optimal configuration scheme of distribution network capacitors based on eliminating resonance is proposed.Firstly,this thesis reviews the domestic and international research on the capacitor layout scheme of distribution network,and finds that there is no effective capacitor elimination configuration method in various schemes.On the basis of studying the domestic and foreign algorithms of identifying series-parallel resonance in power grid,a method of identifying branch series resonance is proposed.Secondly,the typical algorithm for power flow calculation of the distribution network is studied,including the fundamental power flow algorithm and the harmonic power flow algorithm,and IMB/FSM is proposed.Moreover,the PSO is studied,and its iterative optimization mechanism and the influence of parameters on the convergence of the algorithm are analyzed.An improved C-SA-PSO algorithm is proposed.Meanwhile,several multi-objective particle swarm optimization algorithms are compared and analyzed,and VE-PSOml is chosen to study multi-objective problems.Finally,this thesis takes the IEEE33 distribution system as the simulation research object,by inserting harmonic source into the distribution system,establishes the distribution system model with nonlinear load.Using the scheme proposed in this thesis,a mathematical model with economic optimization as a single objective function and NPV and max ?V as a multi-objective function is established,and the capacitor configuration of the distribution system model with non-linear load is optimized by using PSO.Simulation results and modal analysis show that this scheme can effectively avoid the resonance caused by the unreasonable installation of capacitors,resulting in the damage of power grid and electrical equipment.This thesis provides a solution for capacitor configuration in the early stage of distribution network construction and operation.