摘要:Voltage stability is a major concern in heavily loaded distribution networks.Careful determination of control parameters for loadability enhancement may maximize the utilization of distribution networks.In applicable studies,most of the approaches optimize real/reactive power losses for the current operating conditions of the distribution network.Although,these types of approaches increase the stability margin,such an increase may not be sufficient.The most important factor in loadability enhancement is representation of future load scenarios in addressing the optimization problem.In this paper a look ahead approach is developed for loadability enhancement of an unbalanced distribution system.The determination of the critical loading point is conventionally done using continuation power flow,which is computationally very demanding,and also complex for implementation in unbalanced distribution networks.Therefore,a new,computationally very efficient voltage stability indicator is developed here for determination of the loadability limit.The proposed methodology is demonstrated on IEEE 4 bus and 25 bus unbalanced distribution systems with different transformer connections.
摘要:Urban electricity and heat networks (UEHN) consist of the coupling and interactions between electric power systems and district heating systems,in which the geographical and functional features of integrated energy systems are demonstrated.UEHN have been expected to provide an effective way to accommodate the intermittent and unpredictable renewable energy sources,in which the application of stochastic optimization approaches to UEHN analysis is highly desired.In this paper,we propose a chance-constrained coordinated optimization approach for UEHN considering the uncertainties in electricity loads,heat loads,and photovoltaic outputs,as well as the correlations between these uncertain sources.A solution strategy,which combines the Latin Hypercube Sampling Monte Carlo Simulation (LHSMCS) approach and a heuristic algorithm,is specifically designed to deal with the proposed chance-constrained coordinated optimization.Finally,test results on an UEHN comprised of a modified IEEE 33-bus system and a 32-node district heating system at Barry Island have verified the feasibility and effectiveness of the proposed framework.
摘要:Charging piles are used for charging electric vehicles and are directly accessible to users in an energy internet entrance,while playing an important role in energy consumption.Currently,each enterprise constructs the center of operation and maintenance of their systems independently,along with their respective APP payment programs.This results in high operating costs,poor user experience,and low utilization rate of the pile,which limits the promotion and popularization of electric vehicles.To overcome this limitation,there is a need for a multi-center,fair,and transparent consortium blockchain,which can conform to the application requirements of a unified payment system and accommodate a range of diverse enterprise charging piles.In this paper,the design for a consensus and incentive program for consortium blockchain is presented.First,the application status of blockchain in an energy internet is described.Then,the logical structure and hierarchical model of the consortium blockchain are analyzed.Next,multicycle accounting and limiting the amount of accounting nodes in each round is presented to ensure the overhead of consensus remain constant.Finally,the accounting incentive mechanism and the bidding encouragement strategy based on "electric beans" are designed.
摘要:Sub-synchronous oscillation (SSO) incidents caused by dynamic interaction between wind farms and power system grids can threaten safe and reliable operations.This paper investigates mechanism studies of SSOs in power systems induced by grid-connected wind farms.First,characteristics of several severe SSO incidents encountered by real power systems caused by grid-connected wind farms are introduced.Second,in terms of principles and responses,this paper illustrates the most commonly adopted mechanism investigation methods for SSOs,which include impedance-based analysis (IMA) and the openloop modal analysis (OMA) methods.Systematic reviews that summarize existing studies using the IMA and OMA methods are discussed in this paper.Furthermore,a discussion of the current research gaps in the investigation of SSOs in power systems caused by grid-connected wind farms is presented.
摘要:Buildings have both high as well as flexible energy demands and play an important role in the energy internet solution.The buildings' energy flexibility (BEF) is a widely recognized concept;however,how to unlock its potential is a relatively new research topic.In this paper,the authors provide an overview of the latest research related to BEF.An introduction to BEF is provided,methods developed for identifying and characterizing BEF are presented,and several key influencing factors are identified.The overview also covers various aggregation methods to scale up BEF impacts and service-oriented solutions for enabling BEF applications in different energy sectors.This work lays the groundwork for designing and developing seamless integration strategies for BEF use in both present and future energy systems.
摘要:The Journal of Control Theory and Applications(JCTA) publishes high-quality papers on the theory,design and applications in the systems and control field.This journal is published quarterly.Three types