Comparative case studies for value-based distribution system reliability planning

This paper will develop a set of reliability worth evaluation models to evaluate the load point reliability worth indices for five different distribution types. The distribution substations, primary distribution systems, and the interaction between them contribute to the load point reliability worth indices. The reliability worth of the distribution systems are evaluated in terms of customer interruption costs, by using the sector customer damage function (SCDF). The most suitable system design is based on comparisons of the total system costs of the candidates under consideration. Four case studies are thoroughly examined in this paper. Also, the impact on customer interruption costs associated with customer type, substation configuration, and feeder configuration are investigated.     

Value-based distribution system reliability planning

Society is becoming increasingly dependent on a cost-effective reliable electric power supply. Unreliable electric power supplies can be extremely costly to electric utilities and their customers. Predictive reliability assessment combines historical outage data and mathematical models to estimate the performance of specific network and system configurations [e.g., IEEE Std. 493-1990]. This paper is concerned with the value-based assessment of proposed modifications to an existing industrial distribution system configuration to minimize the costs of interruptions to both the utility and its industrial customers. This paper presents a series of case studies of an actual industrial load area supplied by two feeder circuits originating from two alternate substations. Each case study reveals the impact on the cost of industrial load point interruptions and the frequency and duration of industrial load point interruptions when various system constraints (e.g., ideal and nonideal protection coordination schemes, substation capacity restrictions, etc.) are imposed on the distribution system. The paper discusses in some detail the variance in reliability performance indexes and their impact on the cost of load point interruptions. A basic conclusion of this paper is that expansion plans of an industrial distribution system can be optimized in terms of reliability by using an economic criterion in which the sum of both the industrial facility interruptions and the utility system costs are minimized     

Power system reliability planning practices in North America

The authors present selected results from a recently completed research project for the Electric Power Research Institute. One component of the project was intended to develop and test methodologies for gathering data on how utility customers value service reliability, as measured by either the cost of outages or the willingness to pay for reliability. Another component of this project involved a survey of current and emerging reliability planning practices in the North American utility industry, especially regarding interest in value-based reliability planning. The results of the survey, including the survey design and methodology, are given. The authors briefly discuss potential applications of interruption costs in generation and composite system reliability planning     

Value-based distribution reliability assessment and planning

This paper presents a reliability assessment method for radial distribution systems. It combines, the radial network reliability and the customer interruption costs to form the Value-Based Distribution Reliability Assessment (VBDRA) methodology, which is a valuable tool for distribution system planning incorporating customer interruption costs. The proposed method is implemented in a Lotus 1-2-3 macro program with a specially designed data structure for the radial network. The analysis of the proposed computational method shows that the method is valid and fast in practical applications. Various applications of VBDRA planning at the Scarborough Public Utilities are reported in the paper     

A new look at component maintenance practices and their effect on customer, station and system reliability

This paper introduces a new concept in the analysis of the effect of changes in maintenance policies on component, delivery point and bulk electric system reliability and associated costs. In the new approach several different analysis methods are combined, allowing for a comprehensive look at the effect of maintenance and reliability issues. This approach has been made possible by a development of a computer platform, which seamlessly links several complex computer programs. The concepts of the new approach and the implementation of the computer platform are presented in this paper. A numerical example illustrating implementation of these concepts is also presented.     

Value-based power system reliability planning

In a competitive energy market, in which power supply reliability can influence customer purchasing decisions, electric utilities throughout the world are rapidly recognizing that they cannot ignore customer preferences. Today's energy market is characterized by intense price competition, and electric utilities are faced with new challenges of large debts, budget constraints, safety, environment and economic issues, lower load growth than in the past, need for more involvement of public at large in the planning and design process, and more competitive nonconventional suppliers of electricity. In addition, in a deregulated competitive energy market, electric utilities are under conflicting pressures of providing even higher standards of service reliability and holding the line on rates. Value-based system facility planning offers a rational response to these conflicting customer demands. This paper presents two case studies to illustrate the basic concepts and applications of value-based power system planning. The paper also presents a methodology for determining the unique composite customer cost of interruptions (i.e. damage functions) for changing area system network configurations. These techniques are presently being used in the decision-making processes at Alberta Power Limited, Edmonton, Alta., Canada     

配电网可靠性成本与效益综合

基于配电网可靠性成本与效益的概念，给出了以可靠性成本与可靠性效益相结合作为寻求配电网最优投资策略的目标函数。并根据配电网自身的特点，提出了配电网负荷支路是否设置熔断器的判据以及是否在负荷支路设备用变压器的判据，依照这两个判据，对配电网的投资策略目标函数进行简化，得到更为简单的寻求配电网最优投资策略的目标函数。最后给出一实例。     

基于可靠性的配电网规划的思考

对传统配电网规划方法和基于可靠性的配电网规划方法进行了比较,指出传统规划方法存在的问题,分析了两者的差异,提出开展基于可靠性的配电网规划工作需要解决的一些问题并给出建议。     

规划配电网简化方法及其可靠性评估算法

首先对配电网馈线的负荷和长度进行简化假设,并定义了主干线和分支线;在考虑馈线配变容量约束的基础上,提出了转供率计算方法;把配电网馈线分为主干线、分支线和配变,并由此推导出配电网馈线可靠性指标,利用馈线可靠性指标形成配电系统可靠性指标,另外对网架假设进行误差分析。最后分析了规划配电网可靠性评估需要的数据结构;算例证明了对规划配电网假设和该算法的有效性和可行性。     

考虑路网与配电网可靠性的电动汽车充电站多目标规划

提出一种考虑城市路网和配电网交互的电动汽车充电站规划方法。首先,构建了综合考虑城市路网和配电网可靠性的电动汽车充电站规划问题的数学模型;然后,通过博弈论思想进行博弈仿真,利用所得电动汽车行驶特性开展城市路网可靠性评估,并利用电动汽车的充放电特性度量其对配电网供电可靠性的支撑作用;在此基础上,提出以路网节点为待选站址的优化方法;最后,结合实际城市路网和配电网构造典型算例,通过算例分析验证所提方法的有效性和实用性。     

基于可靠性及经济性的配电自动化差异性规划

配电自动化能够有效地提高供电可靠性,但必须兼顾其可靠性提升效益与投资之间的平衡。综合考虑可靠性和经济性,建立了实施配电自动化后的净收益模型。其中可靠性计算部分所采用的负荷点最小割集算法以及故障修复时间,均针对配电自动化条件进行了修正。结合国家电网公司规定的供电区域分类,研究了可靠性经济性最佳的差异性配电自动化方案。研究表明,B类供电区域推荐采用重合器与分段器配合的就地控制方案、分布式智能终端就地控制方案;产电比在15元/kWh以上的A类供电区域,推荐采用分布式智能终端就地控制方案。对于经济发达、负荷密度大以及可靠性要求高的地区,可考虑采用配电自动化主站集中控制方案,并给出了具体应用的产电比范围。     

复杂配电系统的可靠性评估

采用故障模式与后果分析法(FMEA)结合网络等值的原理对带有分支子馈线的复杂配电系统进行了可靠性评估,并提出了一种简单配电系统的等效逻辑模型.该算法通过网络等值原理将复杂配电系统逐步等值为只有一条馈线的简单配电系统,进而结合等效逻辑模型和FMEA法评估系统的各项可靠性指标,这样就比直接利用FMEA法大大提高了效率.     

复杂配电系统的可靠性评估

采用故障模式与后果分析法(FMEA)结合网络等值的原理对带有分支子馈线的复杂配电系统进行了可靠性评估,并提出了一种简单配电系统的等效逻辑模型。该算法通过网络等值原理将复杂配电系统逐步等值为只有一条馈线的简单配电系统,进而结合等效逻辑模型和FMEA法评估系统的各项可靠性指标,这样就比直接利用FMEA法大大提高了效率。     

配电系统可靠性分析综述

阐述了配电系统可靠性分析的基本概念和常用指标,综合分析了配电系统可靠性常用方法和改进算法。并对现有文献在配电系统可靠性分析方面所作的工作进行了分类,分为可靠性模型的完善、评估算法的改进和工程应用等方面。说明了进一步加强配电系统可靠性研究工作的理论探索和实践应用的必要性,同时指出了今后的研究方向。     

计及经济性与可靠性的台区储能优化配置研究

分布式光伏装机量猛增影响了配电网的安全可靠运行,台区储能成为消纳分布式光伏的关键,但台区储能项目投资的经济性与电网可靠性之间难以平衡。对此,提出一种基于“台区储能反配新能源”新模式的综合考虑经济性与可靠性的台区储能优化配置方法。首先,建立台区储能容量优化经济模型;其次,基于台区储能经济性优化结果进行电网可靠性模拟仿真;最后,考虑经济性与可靠性等综合指标,运用优劣解距离法对各节点进行选址评估,通过累积分布曲线确定台区储能配置方案。算例仿真结果表明文中所提方法可以有效提升配电网分布式光伏消纳能力,更好地平衡了台区储能投资的经济性与电网可靠性,相关结果可为新能源配储比例的合理设置提供借鉴。     

基于特征频带暂态无功功率的配电网故障选线新方法

为解决小电流接地系统在相电压过零点附近特征频带选取结果不准确、保护装置采样不同步等问题,详细分析了零模网络下配电线路的相频特性,并据此提出一种基于特征频带暂态无功功率相关性检测的选线新方法。首先,对各出线暂态零模电流与母线差分零模电压进行交叉小波变换,将二者相关性较强且相位差稳定的区域作为故障选线的时频窗。然后,利用时频窗内暂态电压电流信号的幅值与相位信息计算得到暂态无功功率。最后,根据特征频带内故障线路暂态无功功率与非故障线路暂态无功功率流向相反的特点,利用互相关函数算法对各出线暂态无功功率的相关性进行检测,确定故障线路。理论分析和仿真结果表明,所提方法不受故障初始角、同步误差、噪声干扰等因素的影响,对高阻以及弧光接地具有较强的适应性,且适用于分布式电源接入的配电网单相接地故障选线。     

Discussion of "Application of customer interruption costs in transmission network reliability planning" [and closure]

Shih-Min Hsu comments on the paper by A. A. Chowdhury et al. (see ibid., vol.37, p.1590-6, 2001). He comments on transmission systems reliability and the use of average loads with respect to cost/benefit analysis. The original authors reply to the comments.     

Improved distribution system planning using computational evolution

This paper presents a new problem solving environment that can utilize different forms of resources to approach better solutions in the distribution network planning domain. To implement this concept, a design optimization framework, named design by expectation (DBE), is developed. DBE exploits the adaptation of genetic algorithms in searching the optimal solution, and releases the strict requirements for objective functions and constraints in conventional optimization techniques. One example, street lighting design, is used to demonstrate the applicability of the proposed approach