| In the future,renewable energy will be integrated into the system on an enormous range thanks to its goodness towards environment and economy.With grandly arising construction and deep influence of transmission and distribution network(TDN)on each other,the influence of distributed generation(DG)should be further considered.To manage and optimize TDN,basing on methodology of joint regulation,there is need that all control variables be mobilized to reduce TDN loss and raise voltage stability.In this paper,the subject of TDN reactive power optimization is considered,also including interaction of optimal control of TDN.The research objectives are to reduce the complexity of TDN optimization model,improve the global calculation speed,and meet the real-time online calculation requirements.A series of researches on reactive power synergistic optimization of TDN considering impedance margin are carried out in this paper.Compared with the traditional centralized analysis,a distributed computing method of TDN is adapted,of lower mathematical complexity and higher computation speed,targeting at minimizing network spoilage.AFPSO-IPM is used as the optimization algorithm,under the architecture of individual distribution nets energizing parallel procedures in real-time.Finally,the TDN model and distributed scheme are tested by simulation.Risk of potential voltage troubles brought by vast amount of newly adapted DG source need significant concerns.A distributed TDN reactive power optimization method utilizing impedance margin is proposed.The equivalent parameters and impedance margin at the boundary nodes are obtained through sensitivity analysis.This feature beseems very much the online application.With the methodology of computing impedance ratio according to equivalent parameters,the quantitative calculation results of impedance ratio index under different load types are analyzed,and the evaluation effect of impedance ratio of weak nodes is investigated.Simulation results suggests that the methods are beneficial to alleviating the loss of TDN and enhance impedance margin at boundary nodes.The modeling of DG is introduced considering its dynamic impacts,considering zoning by time.In this paper,a dynamic reactive power optimization model of distributed transmission and distribution network considering impedance margin constraints is constructed.Then the paper adopts an optimization strategy in the dynamic real-time computation,utilizing combined AFPSO-IPM method aimed to serve different control parameters to accelerate calculation.The optimization method of TDN is simulated,as well as analyzing the self-regulation function of distribution nets and the influence of DG.Simulation results show feasibility from TDN dynamic optimization output,and certify that the scheme is applicable for the designated cases. |
