Multiobjective optimal placement of switches and protective devices in electric power distribution systems using ant colony optimization

This paper presents a multiobjective optimization methodology to optimally place switches and protective devices in electric power distribution networks. Identifying the type and location of them is a combinatorial optimization problem described by a nonlinear and nondifferential function. The multiobjective ant colony optimization (MACO) has been applied to this problem to minimize the total cost while simultaneously minimize two distribution network reliability indices including system average interruption frequency index (SAIFI) and system interruption duration index (SAIDI). Actual distribution feeders are used in the tests, and test results have shown that the algorithm can determine the set of optimal nondominated solutions. It allows the utility to obtain the optimal type and location of devices to achieve the best system reliability with the lowest cost.     

基于可靠性及经济性的中压配电网闭环运行方式

介绍了国内外中压配电网闭环运行方式及其特点;综合考虑可靠性及经济性,建立了配电网从开环运行升级为闭环运行的净收益模型,包括一种简化的中压电缆线路可靠性指标,即系统平均停电持续时间(SAIDI)评估模型;探讨了配电网闭环运行适用范围及实施难度。研究表明,国内现有配电网"闭环设计,开环运行"的供电模式限制了供电可靠性的进一步提升。对于经济发达、负荷密度大、有分布式电源接入以及可靠性要求高的地区,在条件允许的情况下,可考虑采用闭环运行方式(主要为来自同一母线的两馈线自环);该运行方式虽然可能增加供电公司的成本,但能够在提升供电可靠性的同时保证良好的社会经济效益。     

小电流接地系统故障选线算法综述

小电流接地系统是配电网普遍的接线方式,由于中低压配电网的中性点不直接接地和受馈线分布电容的影响,在任一馈线发生单相接地故障后,在其他馈线上会产生潜供电流,这给故障选线和配网保护造成很大困难,国内外学者对此进行了广泛而深入的研究并取得了大量的成果。本文在大量阅读相关文献的基础上对小电流故障选线算法进行了一个归纳和综述,并分析各算法的优缺点,最后提出了最为普遍的中性点经消弧线圈接地系统中故障选线的推荐算法。     

配电网增设分支线保护的方法研究

用户事故出门是导致配电网事故跳闸的主要原因之一,影响了配电网的供电可靠性。在分析配网用户事故出门情况及特点的基础上,探讨了在分支线增设保护装置的必要性,并提出了在配网分支线增设熔断器保护的方法。该方法可降低配网事故跳闸次数、保证配网连续可靠运行并且可减少配网线路故障巡查。     

Development of a high-speed switching system for distributionnetworks

This paper describes a high-speed switching system for distribution networks which has been developed with the aim of improving power supply reliability (reducing the number of supply interruptions) of distribution systems. When a fault occurs in conventional distribution systems, the fault section is isolated using a sequential time-out control scheme which requires the reclosing and re-reclosing of the entire system. A major drawback of such systems is that normal sections are also subjected to unnecessary power supply interruptions. In order to resolve this problem, the authors have developed a high-speed switching system which isolates only the fault section without interrupting the power supply to normal sections. This new system can fully restore power to the normal sections and completely isolate the fault section within 500 ms in the case of a ground fault     

基于启发式规则与AHP-CRITIC算法的配电网故障恢复策略

智能配电网的自愈控制对提高整个电力系统的供电可靠性至关重要。针对含分布式电源的配电网故障恢复问题,提出了基于启发式规则与AHP-CRITIC算法的配电网故障恢复策略。首先,通过广度优先搜索的方法遍历停电区域内所有具有黑启动能力的分布式电源,形成孤岛供电。其次,对剩余失电区域采用启发式规则,以生成用于配电网故障恢复的候选方案集。最后,考虑故障恢复的目标,引入负荷容量裕度、负荷转移量、负荷恢复比例、开关操作次数和电压降落五个评价指标,分别计算候选方案的各评价指标。并使用改进的AHP方法和CRITIC方法对方案进行评估。同时引入综合权重并计算各方案与理想点之间的偏离度,确定最优故障恢复方案以恢复剩余失电区域供电。通过算例分析验证了所提方法在解决配电网故障恢复问题上的有效性。     

Optimizing service restoration in distribution systems based on scheduling of crews considering priorities of loads

The service restoration to sound sections within a short period as much as possible, performed after the permanent fault occurs in a distribution system, is significant for maintaining power supply reliability. This paper proposes an efficient method to find service restoration procedures based on fault searching and the optimal work scheduling of crews, considering the power supply priorities of loads and the probability of occurrence of faults. The proposed method is composed of two-stage problems to reduce the outage sections efficiently: (i) the problem to find a series of searching procedures for unknown fault locations in the first stage and (ii) the optimization problem of work schedules of crews in the second stage. In the first stage, the order of operation of switches opened for searching for the fault direction is determined, constituting the searching tree. After that, the proposed optimization method can efficiently solve the work scheduling problem by formulating it as a mixed-integer linear programming problem in the second stage. The computational experiments using a large-scale distribution system model with many remote and manual switches show that the proposed method can provide efficient service restoration procedures within a reasonable computational time.     

三端柔性多状态开关运行控制与示范应用

分布式能源的广泛接入可能会导致诸如配电网电压越限和网络堵塞等多种问题。柔性多状态开关（flexible distribution multi-state switch, FDS）是一种调节能力强、控制灵活性高的新型电力电子设备,可以有效解决间歇性分布式电源（distributed generators, DGs）高比例接入所引起的一系列问题。三端柔性多状态开关可以更安全、可靠和快速地调节系统潮流,通过对有功功率和无功功率的快速、精准控制,进一步实现馈线之间的柔性互联,从而改善系统电压水平,提高供电可靠性。介绍了广东佛山柔性多状态开关示范工程的基本情况,提出含柔性多状态开关的配电网故障自愈控制策略,建立含柔性多状态开关的配电网运行优化和自愈控制的统一模型,并在示范工程实际算例上分析了柔性多状态开关对改善配电网运行状态的作用。结果表明,柔性多状态开关的应用可以有效地改善配电网电压分布,同时提高供电可靠性。     

考虑双向耦合的电-气综合能源系统时序故障恢复方法

电力系统和天然气网络通过双向耦合可以实现高可靠性运行。为解决电-气综合能源系统在发生故障后的恢复问题,提出了一种时序故障恢复方法。一方面,考虑燃气轮机和电转气设备的双向耦合特性,在恢复过程中通过调度其出力大小实现电力-天然气网络的互补共济;另一方面,考虑到恢复过程中大多设备具有时序特性,如储能电池容量、负荷大小、风光机组出力大小以及网络拓扑的变化,建立了一个多时序的故障恢复混合整数规划模型,并通过分段线性化的手段将模型处理得易于求解,从而得出故障恢复过程中最优的拓扑开关操作序列。最后,通过对13节点配电网和6节点配气网的联合仿真证明了所提方法的有效性。     

中压配电网故障处理模式配置研究综述

用户遭受的停电事故主要由中压配电网故障引起,配置合理的故障处理模式是中压配电网安全可靠运行的重要保障.现有配置原则重点关注是否满足供电可靠性要求,对各种故障处理模式在配置上的差异性分析有所不足,影响了配置方案的实际应用效果.为此,文中概述了国内外中压配电网故障处理模式配置的研究现状.对故障监测式、就地重合式、主站集中式和智能分布式等故障处理模式在适用网架结构类型、通信需求、分段开关类型和动作次数、故障处理及恢复非故障区域供电耗时、适用供电区域类型和经济性等多个方面的具体配置进行了分析比较.归纳总结了中压配电网故障处理模式的配置原则.最后,对中压配电网故障处理模式配置的研究方向进行了展望.     

配电网模式化故障处理方法研究

为充分发挥配电网模式化接线的优点并实现配电网故障处理与模式化接线的配合,提出对配电网采用模式化的故障处理方法,该方法利用变电站出线开关与分支线开关2级保护配合实现分支线或用户故障的就地切除。在此基础上通过对配电网各种典型接线模式特点的分析,分别建议了各种典型接线配电网在主干线或者电源点发生故障后的模式化故障处理步骤,包...     

配电自动化终端布点优化的动态规划研究

提高配电系统的供电可靠性是配电自动化系统建设的重要目标,但需考虑配电自动化设备的经济成本,且实际工程中通常是分阶段拨款。提出一种考虑供电可靠性和经济成本的配电自动化终端布点优化的动态规划方法,混合使用多种类型配电终端,在架空线安装故障指示器、电压时间型终端、电压电流型终端,在电缆线安装故障指示器、二遥终端和三遥终端,根据自动化终端类型确定故障影响模式。运用JAVA语言进行编程,实现从XML文件读取配网数据。以开关为边界划分配电网的区域节点,采用开源的图形库JGraphT存储配网拓扑信息。考虑故障停电情况,以用户年平均故障停电时间为评价供电可靠性的指标,分别建立以可靠性指标为优化目标和以投资总额为优化目标的配电自动化终端布点优化的动态规划模型。使用建模系统GAMS求解模型,得到配电终端布点优化结果。采用某地区区域配电网自动化终端布点规划作为算例验证,结果显示了该方法的可行性与优越性,为类似实际工程提供借鉴与依据。     

实现配电环网可靠自动转供电功能的关键策略

配网馈线自动化是提高供电可靠性的有效措施,是智能电网建设的重要一环。对目前普遍应用的就地型馈线自动化装置自动转供电的策略进行分析、研究,指出该动作策略设计上的不足及可能给电力系统及运行管理带来的危险,并以中山供电局作为典型案例,提出了对联络开关FA装置进行技术改造等以实现可靠的配电环网自动转供电目标的解决方案,为配网馈线自动化的深层应用及开发提供参考。     

计及馈线自动化故障处理全过程的配电终端优化布置方法

为了进一步提高配电网供电可靠性,提出了一种计及馈线自动化(feeder automation, FA)故障处理过程的配电终端优化布置方法。首先以自适应综合型FA模式为例,分析FA的故障定位、隔离与恢复供电的故障处理全过程,并基于电力系统仿真软件DIgSILENT建立了配电终端的动作信号逻辑模型。其次,在考虑了FA故障处理过程的条件下,计算包括故障区域与非故障区域的总负荷停电损失成本,与总投资成本共同构成模型目标函数。考虑系统平均供电可用率指标约束等因素,建立配电终端优化布置模型。然后,基于整数编码的人工蜂群算法确定配电终端最优安装总数,制定配电终端最优配置方案,计算出配电终端最优选址方案。最后,以冀北某地区10 k V配电网作为仿真算例,基于DIgSILENT模拟FA故障处理全过程,验证所提方法的有效性和适用性。     

基于非线性混合整数规划的配电终端布点优化研究

提出一种考虑供电可靠性和经济成本的配电自动化终端布点优化方法,在架空馈线安装故障指示器、电压时间型终端和电压电流型终端,在电缆馈线安装故障指示器、二遥终端和三遥终端,对配网进行配电自动化改造以提高供电可靠性,可靠性指标取为用户年平均故障停电时间,故障影响模式根据配电终端类型确定。用Java语言编程实现,从XML文件读取配网数据,使用JGraphT图形库存储配网拓扑信息,建立非线性混合整数规划模型,使用建模系统Gams求解模型,为便于工程实施,分阶段输出优化结果。采用某市的配电终端布点规划作为算例,验证了方法的可行性。     

Protective relaying for multi-source generator buses

The reliability of an industrial power system can be increased by proper selection and application of protective relays. This is especially true for the medium-voltage distribution system. An effective protective relay application scheme is presented that uses devices widely used in present pulp and paper mill power distribution systems. The effective use of summation overcurrent and directional overcurrent relays for multisource generator buses makes it possible for the power system protective engineer to achieve good selective operation between source buses for both phase and ground fault current conditions. This greatly enhances the reliability of the power distribution system     

A new large scale DAS in CEPCO

The Chubu Electric Power Company (CEPCO) has developed the distribution automation system (DAS) by using minicomputers which monitor and control large and complex distribution networks with maximum reliability and promptness. A significant curtailment of the restoration operation time due to the occurrence of faults is expected by the introduction of the DAS. The authors introduce the DAS that was installed at CEPCO's Kita Utility Office in December 1989 and report on its operation performance. The objectives of the DAS are to enhance the reliability of the power supply, to improve the service quality for customers, and to improve the efficiency in facility utilization. The DAS connects the utility office online with the supervisory control and data acquisition (SCADA) system at the control center and the total distribution management system at the head office, and it has unique functions that will contribute to integrated distribution automation     

计及柔性直流装置的交直流配电网保护控制研究

交直流混合配电网可更好地接纳分布式电源和直流负荷,缓解城市电网站点走廊有限与负荷密度高的矛盾,已成为现代城市配电网的一个重要发展趋势。接入柔性环网控制装置后,配网由单端电源供电网络变为多端电源供电网络,其可靠性面临新的挑战。通过对交直流混合配电系统的故障特点进行总结,分析接入柔性直流控制装置后柔直侧及系统侧的保护影响,提出基于时序配合的智能装置协同控制架构。利用柔性电力电子器件的快速响应特性,设计柔性直流控制装置与交流保护控制装置配合的保护控制策略。在GOOSE有向节点及快速通信机制的作用下,运用保护控制协同策略进行故障定位及隔离,有效地增强了含柔性互联装置的交直流混合配电网可靠性,具有工程实用价值。     

基于最大供电能力的智能配电网规划与运行新思路

探讨了智能电网背景下的配电网建设规划和运行新模式,提出了配电系统高效规划建设与运行的理念。首先,指出快速网络转供能力是未来智能配电网一个新的边界条件,并介绍了计及该边界条件的供电能力理论。然后,在此基础上对目前中国配电网发展面临的问题进行了探讨:大量建设改造后的配电网具备很大的供电能力挖掘空间,通过网架优化能达到降低容载比和大量节约电网投资的效果;配电自动化等二次系统投资的主要效益在于提高一次系统的利用率;复杂的联络配电网络存在简化的必要性和可行性;网架结构和导线型号在标准化的同时也应具有个性化特点;智能配电网调度运行的发展方向是建立基于安全监视、报警、控制及优化安全框架的高效运行体系。最后,提出了适用于成熟配电网的基于供电能力优化的新规划思路,并给出示例。其特点是优先利用已有网络消纳新增负荷,其次再考虑新增变电容量。     

Development of an expert system for analyzing faults in power systems based on waveform recognition by artificial neural networks

In restoration of a power system, appropriate steps need to be taken in early stages to avoid damage to the public caused by insufficient power supply. The first step in the restoration is the analysis of the fault that has produced the power failure. Today, a large amount of data will be available at the occurrence of a fault due to the use of advanced communication systems using digital relays and optical fibers. Such systems are intended to obtain data from the relays and circuit breakers (CBs) under operation and the voltage and current during operation and the prefault and postfault periods. This paper presents a hybrid fault analyzing expert system using data based on protective devices and phasor measurement. This system is a combination of an artificial neural network (ANN) and an expert system (ES). The ANN is used to simplify the analysis of current and voltage waveforms, which is considered difficult due to the presence of a fault resistance and the line impedance. Since a fault waveforms contains various ambiguous factors depending on the nature of the fault resistance, load current and other system parameters, the use of ANN is effective making such determinations.