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Research On Control Method Of Middle Low Voltage Network With Distributed Photovoltaic

Posted on:2019-07-04Degree:MasterType:Thesis
Country:ChinaCandidate:C LuFull Text:PDF
GTID:2392330623462446Subject:Electrical engineering
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This paper studies the centralized optimization scheduling and distributed coordinated control of distribution network with high penetration of photovoltaic(PV)and applies the distributed optimization algorithm to the coordinated control of flexible interconnected microgrid.The main work includes the following aspects.1)Aimed at the day-ahead scheduling problem for incremental distribution network,a quadratically constrained quadratic program(QCQP)is proposed,minimizing the total operating cost and considering the adjustment of on load tap changer(OLTC),static var compensator(SVC)in substation,and the reactive power control(RPC)of PV converters and charge and discharge of the energy storage system(ESS)at user side.By linearizing and second-order cone relaxation(SOCR),the NP-hard problem is transformed into a mixed integer second-order cone program(MISOCP).To reduce excessive relaxation error,a multi-period cutting plane(MPCP)is proposed to calculate the optimal power flow in the distribution network and ensure the precision of SOCR.2)Aimed at the distributed scheduling of distribution network with high penetration of PV,the step voltage regulator(SVR)is installed according to the voltage loss rate of full load scenario,and the network is partitioned into different regions.The regional controller optimizes the model by local objective function and constraints and received the boundary information shared by adjacent regions and performs the regional distributed coordinated optimization control based on the alternative direction multiplier method(ADMM).Based on the branch and bound method(BBM),the integer constraint of SVR tap is transformed into the regional boundary voltage inequality constraint,which solves the nonconvexity introduced by the multiplication of the tap position and voltage and guarantees the convergence of ADMM.3)A flexible interconnection method based on bidirectional AC/DC converter is used to connect independent microgrids around the interconnection operation control problem between different microgrids.Each microgrid and the AC side of the connected converter constitute a control area separately.Intra-area networks centrally optimize the PV unit,ESS and diesel engine generator(DEG).The active power at the boundary is interacted with each other,and interconnected areas carries out distributed optimization algorithm based on ADMM to coordinate the control resources in different microgrids to achieve the overall economic operation.
Keywords/Search Tags:Distributed photovoltaic, Incremental distribution network, Flexible interconnected microgrid, Mixed integer second-order cone program, Multi-period cutting plane, Distributed coordinated control
PDF Full Text Request
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