With the progressive exhaustion of fossil energy and growing concerns about climate change,it has been ob served that distributed energy resources such as photovoltaic(PV)systems and electric vehicles(EVs)are being in...With the progressive exhaustion of fossil energy and growing concerns about climate change,it has been ob served that distributed energy resources such as photovoltaic(PV)systems and electric vehicles(EVs)are being increasingly integrated into distribution systems.This underscores the in creasing imperative for a thorough analysis to evaluate reliabili ty from the perspectives of distribution systems and EV charg ing services,taking into account the stochastic nature of PV and EV load demands.This paper presents an approach for the reliability assessment of distribution systems that incorporate PV and EVs considering reliability models for both PV systems and EV battery systems.It also defines new indices to investi gate the adequacy and customer-side reliability for EV charging services.The developed methodology utilizes a Monte Carlo simulation-based approach and is showcased using the modified Roy Billinton Test System(RBTS)Bus 4 distribution system.The results illustrate that reliability indices for EV charging ser vices,such as percentage of charging energy not supplied(PCENS),average EV interruption frequency index(AEVIFI)and average EV interruption duration index(AEVIDI),are im proved under the proposed approach.展开更多
Taking into account the whole system structure and the component reliability estimation uncertainty, a system reliability estimation method based on probability and statistical theory for distributed monitoring system...Taking into account the whole system structure and the component reliability estimation uncertainty, a system reliability estimation method based on probability and statistical theory for distributed monitoring systems is presented. The variance and confidence intervals of the system reliability estimation are obtained by expressing system reliability as a linear sum of products of higher order moments of component reliability estimates when the number of component or system survivals obeys binomial distribution. The eigenfunction of binomial distribution is used to determine the moments of component reliability estimates, and a symbolic matrix which can facilitate the search of explicit system reliability estimates is proposed. Furthermore, a case of application is used to illustrate the procedure, and with the help of this example, various issues such as the applicability of this estimation model, and measures to improve system reliability of monitoring systems are discussed.展开更多
An analytical calculation method for the reliability sensitivity indexes of distribution systems is proposed to explicitly quantify the impact of various influence factors on system reliability.Firstly,the analytical ...An analytical calculation method for the reliability sensitivity indexes of distribution systems is proposed to explicitly quantify the impact of various influence factors on system reliability.Firstly,the analytical calculation formulas for the reliability indexes of distribution systems are derived based on the fault incidence matrix(FIM).Secondly,the factors that affect system reliability are divided into two categories:quantifiable parameter factors and non-quantifiable network structure factors.The sensitivity indexes for the quantifiable parameter factors are derived using the direct partial derivation of the reliability calculation formulas.The sensitivity indexes for the nonquantifiable network structure factors are derived using the transformation of FIMs.Finally,the accuracy and efficiency of the proposed sensitivity calculation method are verified by applying them to an IEEE 6-bus RBTS system.This paper sums up the factors that influence system reliability in detail and gives the explicit analytical calculation method for the sensitivity of each factor.Repetitive calculation of the reliability index can be avoided during the sensitivity analysis.The bottleneck that affects the reliability level of distribution systems can be identified efficiently,and valuable information and guidance can be provided to enhance the reliability of distribution systems.展开更多
This study proposes a new method which aims to optimally install tie-lines and distributed generations simultaneously.This is done to optimize the post-outage reconfiguration and minimize energy losses and energy not ...This study proposes a new method which aims to optimally install tie-lines and distributed generations simultaneously.This is done to optimize the post-outage reconfiguration and minimize energy losses and energy not supplied of distribution systems.The number and location of tie-lines,as well as the number,size,and location of DGs,are pinpointed through teaching the learning-based optimization(TLBO)method.The objective function in the current research is to minimize the costs pertaining to the investment,operation,energy losses,and energies not supplied.In addition to the normal operational condition,fault operational condition is also evaluated.Therefore,the optimal post-fault reconfigurations for fault occurrences in all lines are established.Moreover,the operational constraints such as the voltage and line current limits are taken into account in both normal and post-fault operational modes.Finally,the modified IEEE 33-bus and 69-bus distribution test systems are selected and tested to demonstrate the effectiveness of the simultaneous placement of DGs and tie-line technique proposed in this paper.展开更多
文摘With the progressive exhaustion of fossil energy and growing concerns about climate change,it has been ob served that distributed energy resources such as photovoltaic(PV)systems and electric vehicles(EVs)are being increasingly integrated into distribution systems.This underscores the in creasing imperative for a thorough analysis to evaluate reliabili ty from the perspectives of distribution systems and EV charg ing services,taking into account the stochastic nature of PV and EV load demands.This paper presents an approach for the reliability assessment of distribution systems that incorporate PV and EVs considering reliability models for both PV systems and EV battery systems.It also defines new indices to investi gate the adequacy and customer-side reliability for EV charging services.The developed methodology utilizes a Monte Carlo simulation-based approach and is showcased using the modified Roy Billinton Test System(RBTS)Bus 4 distribution system.The results illustrate that reliability indices for EV charging ser vices,such as percentage of charging energy not supplied(PCENS),average EV interruption frequency index(AEVIFI)and average EV interruption duration index(AEVIDI),are im proved under the proposed approach.
基金This project is supported by National Natural Science Foundation of China(No.50335020,No.50205009)Laboratory of Intelligence Manufacturing Technology of Ministry of Education of China(No.J100301).
文摘Taking into account the whole system structure and the component reliability estimation uncertainty, a system reliability estimation method based on probability and statistical theory for distributed monitoring systems is presented. The variance and confidence intervals of the system reliability estimation are obtained by expressing system reliability as a linear sum of products of higher order moments of component reliability estimates when the number of component or system survivals obeys binomial distribution. The eigenfunction of binomial distribution is used to determine the moments of component reliability estimates, and a symbolic matrix which can facilitate the search of explicit system reliability estimates is proposed. Furthermore, a case of application is used to illustrate the procedure, and with the help of this example, various issues such as the applicability of this estimation model, and measures to improve system reliability of monitoring systems are discussed.
基金supported in part by the National Key Research and Development Program of China(No.2016YFB0900100)in part by the National Natural Science Foundation of China(No.51977140,No.U1866207,No.51207101)+1 种基金in part by the Natural Science Foundation of Tianjin(No.19JCYBJC21300)in part by the Science and Technology Projects of China Southern Power Grid(No.060100KK52170118)。
文摘An analytical calculation method for the reliability sensitivity indexes of distribution systems is proposed to explicitly quantify the impact of various influence factors on system reliability.Firstly,the analytical calculation formulas for the reliability indexes of distribution systems are derived based on the fault incidence matrix(FIM).Secondly,the factors that affect system reliability are divided into two categories:quantifiable parameter factors and non-quantifiable network structure factors.The sensitivity indexes for the quantifiable parameter factors are derived using the direct partial derivation of the reliability calculation formulas.The sensitivity indexes for the nonquantifiable network structure factors are derived using the transformation of FIMs.Finally,the accuracy and efficiency of the proposed sensitivity calculation method are verified by applying them to an IEEE 6-bus RBTS system.This paper sums up the factors that influence system reliability in detail and gives the explicit analytical calculation method for the sensitivity of each factor.Repetitive calculation of the reliability index can be avoided during the sensitivity analysis.The bottleneck that affects the reliability level of distribution systems can be identified efficiently,and valuable information and guidance can be provided to enhance the reliability of distribution systems.
文摘This study proposes a new method which aims to optimally install tie-lines and distributed generations simultaneously.This is done to optimize the post-outage reconfiguration and minimize energy losses and energy not supplied of distribution systems.The number and location of tie-lines,as well as the number,size,and location of DGs,are pinpointed through teaching the learning-based optimization(TLBO)method.The objective function in the current research is to minimize the costs pertaining to the investment,operation,energy losses,and energies not supplied.In addition to the normal operational condition,fault operational condition is also evaluated.Therefore,the optimal post-fault reconfigurations for fault occurrences in all lines are established.Moreover,the operational constraints such as the voltage and line current limits are taken into account in both normal and post-fault operational modes.Finally,the modified IEEE 33-bus and 69-bus distribution test systems are selected and tested to demonstrate the effectiveness of the simultaneous placement of DGs and tie-line technique proposed in this paper.
