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The Optimal Dispatch Of Flexibility Resources For Active Distribution Systems

Posted on:2019-12-11Degree:MasterType:Thesis
Country:ChinaCandidate:M S TangFull Text:PDF
GTID:2382330545950841Subject:Power system and its automation
Abstract/Summary:PDF Full Text Request
Government's incentives and ecological constraints have led to the development of technologies related to distributed energy.The active distribution system(ADS)is a new technology concentrated on power grid intelligence.It paves the way for the integration of clean energy,and is effective to achieve a high proportion of renewable energy sources(RES)for power system operation.This paper focus on the optimal dispatch of flexibility resources for ADS and studies from the following three aspects:1)Power and flexibility resources scheduling for ADS.The output of intermittent RES such as wind power and photovoltaics is uncertain.On the one hand,the integration of RES alleviate the global fossil fuel crisis and improve the atmospheric environment.On the other hand,it brings problems for the safe operation of power system,such as the off-limit of branch flow and node voltage.The ADS operation strategy is designed to coordinate the flexibility of the sources-network-load,and achieve the optimal management of RES and DFACTS,and improve energy efficiency.In the framework of the typical European and American electricity market,the allocation of flexibility resources based on two-stage stochastic programming is to deal with the uncertainty of RES.2)Research on the optimal scheduling of flexibility resources with non-ideal communication.The vulnerability of distribution networks,the uncertainties of communication system,and the lack of motivation to optimize system operation have become the obstacles to the integration of RES.As an important flexibility resource of ADS,the controllable loads can smooth the output of net load and alleviate the fluctuation of RES output.The ability of controllable loads to provide flexibility is not only constrained by itself,but also by the communication systems.The development of ADS must be based on reliable communication quality.However,the current status is that the communication quality of distribution network is weaker than that of transmission network.Therefore,the communication system of distribution network cannot guarantee reliable communication service,and some controllable loads' data cannot be uploaded to control center.The chance constrained optimization method is applied to deal with the uncertainty of controllable load when providing flexibility,and regulatory decisions are made based on the trade-off between economic performance and safety of power system.3)The congestion control taking into account the network-side flexibility resources.DFACTS are a kind of power electronic equipment widely used in the distribution system,which can relieve the line congestion and adjust the node voltage.The soft open point(SOP)is taking as an example of DFACTS,whose function is to increase the proportion of RES by developing the network-side flexibility of distribution system.Compared with traditional tie switch,SOP can achieve active and accurate control of two feeders' active power and can regulate its reactive power output flexibly.The optimal siting and size of SOP is decided considering line flow congestion factor.With SOP,the distribution of distribution system power flow is changed and the power transmission capability of each line is fully utilized.
Keywords/Search Tags:active distribution system, flexibility, stochastic optimization, communication uncertainty, soft open point, congestion management
PDF Full Text Request
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