Distributed nature of residential customer outage costs

Reliability worth assessment is an important factor in power system planning and operation. An equally important issue is how to use customer costs of electric supply interruptions as surrogates to appropriately quantify reliability worth. Postal or in-person surveys of electric customers are often used to determine interruption costs. The results obtained from the surveys are transformed into customer damage functions which are applicable to individual customer classes and sectors. Standard customer damage functions use aggregate or average customer costs for selected outage durations. This paper develops a practical alternative to the customer damage function method of describing the interruption cost data. The alternate technique, which is designated as the probability distribution approach, is capable of recognizing the dispersed nature of the data. The proposed probability distribution method is illustrated in this paper using the interruption cost data collected in a 1991 survey of the Canadian residential sector     

基于GA的发输电合成系统最优可靠性计算新方法

将可靠性和经济性相结合,提出了基于总拥有费用法的发输电合成系统最优可靠性算法的总体框架,进而在概率安全性和概率充裕度综合评估基础上,将综合评估风险指标和可靠性经济评估理论相结合,建立了基于遗传算法和蒙特卡罗仿真相结合的最优可靠性计算模型和算法。算法使最终求得的各元件的最优解所对应的规划方案的总成本最小。最后对IEEE—RTS标准测试系统进行了计算,结果表明所提模型和算法是可行的。     

考虑负荷转移限制的配电系统区间可靠性评估

提出一种考虑线路容量和电压约束的配电系统区间可靠性评估方法。应用区间理论计算了由于元件和负荷参数的不确定性对配电系统可靠性的影响。考虑到网络运行条件对负荷转移的限制,通过区间潮流计算确定故障恢复过程中的网络状态,如果违反网络约束,则以最小化停电损失费用和网损费用为目标函数切除网络中的负荷。结合馈线分区方法,简化了系统结构,提高了计算速度。算例中,分析了参数不确定性条件下负荷转移限制对配电系统可靠性的影响,证明了该方法的有效性。     

Dynamic reliability assessment for bilateral contract electricity providers in restructured power systems

This paper presents a new method to evaluate dynamic reliability indices for bilateral contract electricity providers in restructured power systems. The proposed method is based on the combination of stochastic processes methods and the universal generating function technique. It can provide dynamic reliability assessment for bilateral providers in restructured power systems. In the proposed method, generating units are represented as multi-state models (up to 10 states and more), which are more accurate than the conventional binary-state models. To avoid the “dimension damnation” problem caused by solving the stochastic process model of the entire system, only the stochastic model for each unit is solved. The state probabilities for the bilateral contract electricity provider and the corresponding reliability indices are evaluated by using simple algebraic operations based on the universal generating function technique. Moreover, techniques for the reliability evaluation of bilateral contract electricity provider considering reserve agreements with other generation companies are also proposed in this paper. An example considering different types of generating units from industry is used to illustrate the proposed method.     

考虑容量约束的配电系统可靠性评估

提出了一种考虑线路容量约束的配电系统可靠性评估模型,并开发了其软件。可靠性评估通过故障影响分析实现。这样,开发的软件既可评估全部失去连续性事件的可靠性,又可以评估部分失去连续性事件的可靠性。可靠性指标是：系统平均停电频率、系统平均停电持续时间、用户平均停电频率、用户平均停电持续时间、平均供电可用率、缺供电量、平均缺供电量。经对IEEE配电测试系统DRTS的测试表明,该软件是有效、可用的。     

基于有向图和序贯蒙特卡洛法的含电动汽车配电网可靠性评估

大规模电动汽车接入后将对配电网可靠性带来极大影响,快速有效的可靠性评估方法是亟待解决的关键问题之一。针对含电动汽车的配电网,提出了一种基于有向图和序贯蒙特卡洛算法的可靠性评估方法。首先基于有向图矩阵,利用前推和回推搜索辨识系统故障后的局部网络,并构建系统故障模式影响分析表;分析提出了考虑电动汽车接入后故障模式影响分析表的修正方法,并基于序贯蒙特卡洛算法定量分析了电动汽车接入后对配电网可靠性带来的影响,并从电动汽车接入位置和接入时段等角度对电动汽车接入电网提出了相应的建议。算例分析的结果表明所提方法能够快速修正电动汽车接入后的系统故障模式影响分析表,并能够适应不同场景下的含电动汽车配电网可靠性评估,为电动汽车合理接入电网提供理论依据。     

考虑可靠性成本的配电网多阶段扩展规划方法

传统的配电网可靠性评估通过模拟组件中断来量化一组事件对供电可靠性的影响,这种基于模拟的可靠性评估方法使得其纳入到配电网扩展规划中需要采用启发式或元启发式方法求解。为了克服启发式或元启发式方法收敛性和局部最优的缺点,文中提出了考虑可靠性成本的配电网多阶段扩展规划的混合整数线性优化模型。该模型建立了配电网可靠性指标(即系统平均停电持续时间指标、系统平均停电频率指标和系统缺供电量)的显式评估表达式,并将其相关的可靠性成本纳入到配电网多级扩展规划目标函数中,以系统运行约束等为约束条件。在24节点、54节点、86节点和138节点四个算例系统上验证了所提出的方法的有效性和适用性。     

电网规划中的模糊可靠性评估方法

在同时考虑随机性不确定事件和模糊性不确定事件对电网规划影响的基础上,综合应用概率论与模糊集合论,提出对电网规划方案进行可靠性评估的模糊可靠性评估方法。应用概率统计理论描述和处理设备与电网运行状态变化以及负荷状态变化的随机性,应用模糊集合论描述设备故障的概率和负荷水平预测值等数值上的糊不确定性,并利用相诮的模糊集合运算得出电网的模糊可靠性指标。通过对ＩＥＥＥ２４节点可靠性测试（ＲＴＳ）进行计算利用Ｍ     

考虑计划停电影响配电系统可靠性评估

将故障模式后果分析法与故障扩散法相结合,考虑计划停电时对配电系统可靠性进行评估。根据停电时间不同对影响负荷点的元件进行分类后,将元件的计划停电范围与故障停电范围区分开,比不考虑计划停电或将设备计划停电参数与故障停电参数直接叠加更加合理。通过可靠性指标对参数的灵敏度分析,确定计划停电参数对可靠性指标的影响程度及确定影响系统可靠性最关键元件,从而指导配网建设。     

Reliability planning for composite electric power systems

This paper proposes a reliability design approach using network flow technique, genetic algorithms, and Monte Carlo simulation for composite electric power systems. With increased emphasis on reliability design and cost control in electric power system planning and operation, particularly in composite electric power system, we are therefore striving to achieve an optimal reliability design solution under a reliability/cost implemented model. Because the floating-point representation is more efficient than the binary representation in genetic algorithms application, and the former also has more robust operators to locate near optimal solutions in most cases, we will employ the floating-point representation. The proposed method primarily finds out the optimal values of reliability indices for the components such that the objective function composed of interruption cost and installation cost is minimized. The reliability indices adopted include expected demand not served (EDNS) and forced outage rate (FOR). Application of the proposed method is demonstrated using a 23-bus test system.     

配电系统开关优化配置的混合整数线性规划模型

配电系统中的开关设备可以有效提高系统的运行可靠性,而开关的种类以及安装的位置对配电系统运行可靠性的影响有所不同。在此背景下,研究了计及可靠性的配电系统中开关优化配置策略。首先介绍了在不同预想故障条件下用户停电时间的计算方法。之后构建了以开关投资费用、运行维修费用和用户停电损失费用之和最小,以可靠性指标在给定阈值内为约束条件的开关优化配置模型。通过对用户停电损失函数线性化处理,将所提出的模型转换为混合整数线性模型,并通过高效商业求解器进行求解。最后,对IEEE RBTS-Bus 4系统和某实际中压配电系统进行测试分析,算例结果说明了所提出的模型与求解方法的基本特征。     

Features that influence composite power system reliability worthassessment

Reliability worth assessment using customer interruption costs is an important element in electric power system planning and operation. This paper deals with two features that affect the composite generation-transmission system reliability worth assessment. One feature is the incorporation of temporal variations in the cost of interruption. This paper illustrates the effect on the expected annual system outage cost of temporal variation in the interruption costs for the residential, agricultural, industrial, commercial and large user sectors. The other aspect considered in this paper is using a probability distribution approach to represent the cost of interruption model. The conventional customer damage function approach utilizes average customer costs while the probability distribution approach recognizes the dispersed nature of the customer outage data. These two methods of cost evaluation are applied to reliability worth assessment in this paper. A sequential Monte Carlo approach incorporating time varying loads is used to conduct all the studies. Case studies performed on two composite test systems show that incorporating time varying costs of interruption for the industrial sector resulted in a significant reduction in the expected outage cost. A comparison of the reliability worth obtained using the customer damage function method (CDF) with the probability distribution approach suggests that using the CDF method may significantly undervalue the reliability worth by a factor of three to four     

Production costing and reliability evaluation for composite systems with outages and uncertainties

A new method based on Monte Carlo simulation for composite power system production costing and reliability evaluation, considering apparatus outage probabilities and load forecast uncertainties, is presented. Random numbers are generated, according to appropriate laws, to simulate the state of the apparatus and the demand of the bus loads. Through successive application of the minimum cost flow algorithm, it is capable of handling the economic dispatch problem existing in the procedures. In this paper, the reliability of the system is measured in terms of expected demand not served (EDNS) and loss of load probability (LOLP). The EDNS and therefore the expected unserved energy (EUE) associated with an expansion plan can be evaluated further as an equivalent penalty cost due to service interruption. This benefits the application of the proposed method for selection between alternatives in power system planning. Another advantage of this method is that an expected power flow pattern is generated as the byproduct. Application of the method is demonstrated using the IEEE five-bus test system.     

考虑多种终端配置的中低压配电网供电可靠性协同评估

针对现有配电网可靠性评估方法无法整体评估到低压,对配电终端类型考虑不全面的问题,提出一种考虑多种终端配置的中低压可靠性协同评估方法.首先,从评估对象、评估指标以及评估框架三方面说明中低压配电网可靠性协同评估的基本思路;其次,结合馈线分区理念,考虑各类终端对供电可靠性的影响,建立基于多模块智能终端设备配置的故障查找与影响...     

计及中长期合同电量分解和风电不确定性的电-气综合能源系统日前优化调度

将中长期合同电量分解模型引入电-气综合能源系统日前调度决策过程中,实现了合同电量分解和调度计划制定的嵌套优化。针对合同电量分解结果可能在实际调度计划中不可执行的情况,提出了一种基于拉格朗日乘子的机组日分解电量越限因素定位方法,并通过中长期合同电量分解模型与日前调度模型的协调迭代消除越限电量,保证了中长期交易的有效性。此外,在模型中考虑了天然气网络约束和风电随机性对中长期交易计划的影响,并利用机会约束规划理论构建含风电不确定性的优化调度随机模型。基于风电等效随机输出样本矩阵和随机模拟技术实现机会约束向确定性表达式转化。通过仿真算例验证了所提方法的有效性。     

Effective techniques for reliability worth assessment in compositepower system networks using Monte Carlo simulation

Reliability cost/reliability worth assessment plays an important role in electric power system planning and operation. The paper proposes a technique for evaluating the costs of interruption and hence, the reliability worth in a composite power system network with time varying loads at load buses using sequential Monte Carlo simulation. A generalized methodology of determining the interruption costs, without considering the time varying aspect of the loads is discussed and the results are compared with those obtained by utilizing a load duration curve to represent the time dependent loads. Case studies conducted on the IEEE Reliability Test System (IEEE-RTS) are presented and discussed     

考虑配网功率约束及可靠供暖的蓄热式电采暖系统优化调度方法

文中提出一种考虑配网功率约束及可靠供暖的蓄热式电采暖系统优化调度方法。首先,基于系统内负荷热需求量构建热负荷预测模型,并对蓄热式电采暖设备与系统建模;进而建立负荷功率曲线模型;最后,以配电网传输功率限制、可靠供暖为约束,构建一种考虑配网约束及可靠供暖的蓄热式电采暖系统优化调度方法。以系统日运行成本最低以及电采暖设备实际消耗功率与电网下发的负荷功率曲线的偏离程度最小为目标,确定电采暖系统的优化调度方案。算例结果表明,所提方法可在考虑配电网功率约束的前提下,能够充分利用蓄热式电采暖的蓄热量,可有效提升配电网运行安全性及用户供暖可靠性。     

基于对话文本智能挖掘的电力设备供应商评价

目前电网企业的电力设备供应商满意度评价主要依赖于人工统计和指标计算,其准确性受评价人员和评价内容的影响较大.以电力业务平台的对话文本为研究对象,在扩充已有电力本体词典的词条和属性的基础上,建立了基于文本挖掘技术的电力设备供应商评价模型.首先提出了基于Transformer的双向编码器下句预测与余弦相似度加权的单轮对话文本下句预测分析方法,建立了对话中断交叉处理流程和供应商识别规则,实现了电力对话文本主题归纳;然后考虑对话文本语义情感的复杂性,提出了对话情感分析规则,建立了供应商评价模型.最后通过算例验证了所提方法的准确性,结果表明基于对话文本智能挖掘的电力设备供应商评价,具有可行性和有效性,可以作为目前评价方法的有益补充.     

考虑最优负荷削减与热负荷惯性的综合能源系统可靠性评估

综合能源系统(integrated energy system,IES)具有灵活调度和多能互济的特点,针对当前综合能源系统供能可靠性研究尚不充分的问题,提出一种考虑最优负荷削减与热负荷惯性的综合能源系统可靠性评估方法。首先,建立了综合能源系统总停供损失期望指标,充分体现了综合能源系统停供能造成的经济损失;其次,考虑能源品位、负荷重要度、热负荷惯性,建立了故障场景下综合考虑运行成本最小与加权停供负荷量最小为目标的综合能源系统最优负荷削减模型,采用CPLEX软件求解获得电热负荷削减功率和元件设备出力;然后,基于序贯蒙特卡洛模拟原理,设计了综合能源系统可靠性评估方法和流程;最后,通过算例仿真进行验证。算例分析表明,采用最优负荷削减策略和考虑热负荷惯性能够有效提升综合能源系统的可靠性水平。     

计及气候因素的大电力系统可靠性评估

研究了电网可靠性评估中计及气候条件因素的问题。针对不同气候条件下的输电线路元件，建立其可靠性模型，采用Monte Carlo方法对气候区域和输电线路进行抽样，确定区域气候状态和输电元件状态。可以处理输电网络或某一输电线路在同一时刻可能处在不同气候条件下的情况。最后介绍了计及气候条件因素的电网可靠性评估程序编制，给出了程序流程图，并通过算例比较计及气候条件与否对可靠性充裕度指标的影响。