考虑继电保护隐性故障的电力系统连锁故障风险评估

提出了考虑继电保护隐性故障的电力系统连锁故障风险评估方法。采用继电保护隐性故障的概率模型描述保护装置对电力系统风险的影响,通过分析保护系统的机理表明保护装置在连锁故障中的作用,用母线孤立风险、负荷孤立风险、电网解列风险及系统综合风险来评估系统的连锁故障风险,并据此提出了减小系统连锁故障风险的预防措施。应用蒙特卡罗方法产生系统事故、保护装置和隐性故障的随机特性,编写了电力系统连锁故障风险评估与预防软件。IEEE118节点系统的应用结果证明了该方法的可行性及软件的有效性。     

海上油田群电力系统节点脆弱性评估

针对以往对海上油田电力系统的可靠性研究只考虑N–1故障,未能深入探究多重故障对系统可靠性影响的问题,考虑海上油田电网特点,提出节点脆弱性的评估方法.首先,基于油田电网历史故障数据建立连锁故障典型事故链,挖掘导致连锁故障问题的主导因素.然后,基于历史故障分析结果,建立了油田电力系统节点脆弱评估模型.该模型根据无功–电压灵...     

基于时序和随机风速模型的含风电场发电系统充裕性评估

建立基于蒙特卡洛模拟(MCS)的含风电场发电系统可靠性评估模型,包含时序和随机风速模型的建立及序贯和非序贯蒙特卡洛模型的建立,并把该模型应用到RBTS测试系统中。由不同风速模型和不同MCS方法构成4种组合可靠性评估模型,本文分析4种组合模型的系统缺电概率LOLP、缺供电时间期望LOLE、期望缺供电量EENS、可靠性指标,并确定时序和随机风速模型及序贯和非序贯MCS方法对系统充裕性的影响,同时分析了风电场装机容量、系统峰值负荷等因素对系统充裕性指标的影响。     

考虑安全性和经济性的连锁故障预防控制策略

为阻止源头性故障引发连锁故障的安全问题,文章提出一种考虑安全性和经济性的连锁故障预防控制策略.首先,根据继电保护的动作特性给出一种判别连锁故障的数学形式.其次,以电网安全裕度和发电运行成本分别评价系统的安全性和经济性,以支路脆弱性评估方法选取初始故障,构建了针对不同初始故障作用下的连锁故障预防控制模型.该模型是一种双层...     

Relay coordination and protection failure effects on reliability indices in an interconnected sub-transmission system

Protection system failure is the main cause of cascading outages. It has been shown that the hidden failures lead to cascading outages. However, the effects of the coordination method as well as the hidden failure of the protection systems have not been investigated yet. In this paper, an algorithm based on sequential Monte Carlo simulation is proposed to find the reliability indices for different overcurrent relay coordination methods. The proposed algorithm is applied to the results of different relay coordination methods of a real network. The indices SAIFI, CAIDI, CAIFI and ENS for the results of different relay coordination methods are obtained strictly based on the contribution of the protection failure issues. Then, a comparison is made between the results of the different relay coordination methods in order to show how the coordination methods affect the reliability indices.     

考虑保护隐藏故障的系统N-k故障分析

存在隐藏故障的继电保护会在系统发生N-1故障时,导致保护误动,对连锁故障扩大起着推波助澜的作用。从保护隐藏故障的动作机制出发,计及不同原理的保护装置和线路故障位置,对保护的隐藏故障模式进行分析,确定保护的风险区段,提出一种基于保护隐藏故障模式分析的N-k故障分析方法,将保护的隐藏故障反映到预想事故的选择和故障组合上。算例表明,采用该方法可定量评估电网中继电保护隐藏故障对系统可靠性的影响,发现系统的薄弱环节。     

Modeling and assessment of station originated outages for compositesystems reliability evaluation

Consideration is given to the impact that terminal-station failure events have on the contingencies of connected lines and generators that should be included in the reliability evaluation of a composite system. Algorithms are described that simulate various failure modes of station components, deduce the resulting contingencies and their reliability indices, group together identical contingencies, and cumulate the resulting reliability indices. This is a novel approach for determining the effect of station failures on station-originated outages. The results can be used to assess the reliability of the stations themselves and as input data to a composite system reliability evaluation technique     

继电保护隐藏故障造成输电线路连锁跳闸的概率模型

继电保护隐藏故障是造成输电线路连锁跳闸的主要原因。通过分析继电保护装置隐藏故障的动作机理,定义了隐藏故障的风险区域,并利用保护装置隐藏故障概率和风险区域故障概率的计算,建立了输电线路连锁跳闸的概率模型。该模型计入了多条输电线路具有不同故障概率对触发继电保护装置隐藏故障的影响,可以评估继电保护系统因隐藏故障造成连锁误切线路的概率。最后,利用实际数据进行的算例分析验证了模型的合理性,计算结果对电力系统可靠性分析及连锁故障风险评估具有参考价值。     

Performance and reliability of electrical power grids under cascading failures

The stability and reliability of electrical power grids are indispensable to the continuous operation of modern cities and critical for preparedness, response, recovery and mitigation in emergence management. Because present power grids in China are often running near their critical operation points, they are especially vulnerable and sensitive to external disturbances such as hurricanes, earthquakes and terrorist attacks, which may trigger cascading failures or blackouts. This paper describes a quantitative investigation of the stability and reliability of power grids with a focus on cascading failures under external disturbances. The 118-bus (substation) power network in Hainan, China is employed as a case study to investigate the risk of cascading failure of the regional power grids. System performance and reliability of the power grids are evaluated under two hypothetical scenarios (seismic impact and intentional disturbance) that could trigger cascading failures. By identifying the most vulnerable (critical) edges and nodes, the robustness of the power network is evaluated under the triggered cascading failures. It is found that the system reliabilities could decline as much as 95% during the triggered cascading failure. This paper also explores the use of concepts from modern complex network theories such as state transition graph and characteristic length to understand the complex mechanism of cascading failures. The findings could be useful for power industries and emergency managers to evaluate the vulnerability of power systems, understand the risk of blackout induced by cascading failures, and improve the resilience of power systems to external disturbances.     

An adaptive supervised wide-area backup protection scheme for transmission lines protection

Maloperation of conventional relays is becoming prevalent due to ever increase in complexity of conventional power grids. They are dominant during power system contingencies like power swing, load encroachment, voltage instability, unbalanced loading, etc. In these situations, adaptive supervised wide-area backup protection (ASWABP) plays a major role in enhancing the power system reliability. A balance between security and dependability of protection is essential to maintain the reliability. This paper proposes multi-phasor measurement units (MPMU) based ASWABP scheme that can function effectively during faults besides power system contingencies. MPMU is an extended version of Phasor Measurement Unit (PMU). It is an intelligent electronic device which estimates the synchronized predominant harmonic phasors (100Hz and 150Hz) along with the fundamental phasors (50Hz) of three phase voltages and currents with high precision. The proposed ASWABP scheme can detect the fault, identify the parent bus, determine the faulty branch and classify the faults using MPMU measurements at System Protection Center (SPC). Based on these MPMU measurements (received at phasor data concentrator (PDC) at SPC) the appropriate relays will be supervised to enhance the overall reliability of the power grid. Numerous case studies are conducted on WSCC-9 bus and IEEE-14 bus systems to illustrate the security and dependability attributes of proposed ASWABP scheme in MATLAB/Simulink environment. Also, comparative studies are performed with the existing conventional distance protection (Mho relays) for corroborating the superiority of the proposed scheme regarding security and dependability. Comparative studies have shown that the proposed scheme can be used as adaptive supervised wide-area backup protection of conventional distance protection     

Anatomy of power system blackouts: preventive relaying strategies

Major blackouts of electric power systems in which many customers are left without power are rare events. However, the effects of blackouts, for instance, can be catastrophic. It has been observed that protective system failures are a contributing factor in a large proportion of these blackouts. The most troublesome protection system failures are hidden failures, which remain dormant during normal system conditions, and are exposed during system disturbances. A study of hidden failures of the protective systems is undertaken to uncover their modes of failures, and to determine means of supervising their actions in times of highly stressed power system operations. The main contribution of this paper is to develop and document a method of quantitative analysis of the significance of hidden failures of protection systems. A complete protection system was designed for the New England 39-bus system and the hidden failure modes were used to develop regions of vulnerability and a vulnerability index. Through this analysis, critical protection systems, whose hidden failures would have a major impact on cascading failures or blackouts of the power system, can be identified These protection systems are candidates for increased monitoring and control, which would help alleviate the problems posed by hidden failures     

考虑保护失效和电网动态平衡特性的连锁故障风险评估

保护失效特性严重威胁了电网安全。同时,现代电网受扰动后可调整线路参数,以减缓故障蔓延,具有典型的动态平衡特性。基于复杂网络理论提出了考虑保护失效特性和动态平衡特性的连锁故障风险评估方法。首先,基于隐性故障,定义了保护失效严重度概念,可度量保护对电网安全的影响程度。其次,结合保护失效严重度,建立了变权重模型,以表征电网故障后动态平衡特性。然后,引入风险理论,从复杂网络理论角度评估电网安全风险,以为实际运行提供指导意义。最后,新英格兰39节点算例系统验证了所提方法的有效性和合理性。     

基于改进状态空间分割法的继电保护设备拒动风险评估

继电保护设备隐性故障已经成为导致电力系统连锁故障的重要因素.因此,在电力系统的风险分析中,需要突破传统N-1故障设置假设,考虑受继电保护设备隐性故障影响的N-k连锁故障.针对继电保护设备拒动引发连锁故障的问题,首先根据继电保护设备的功能模块建立继电保护设备拒动故障树模型;然后综合考虑元件固有失效率和运行信息,建立继电保护设备拒动概率动态评估模型.基于此,提出一种改进的状态空间分割法对电力系统面临的连锁故障风险进行分析,实现了在枚举空间和抽样空间中进行连锁故障搜索,可提高连锁故障搜索的完备性和风险分析的计算效率.最后,在仿真中验证了所提方法的有效性.     

复杂系统理论在电力系统中的应用研究展望

国内外电网在过去十多年来曾发生多次由连锁故障导致的大停电事故,引起人们对电网安全的高度重视,促使人们深入研究连锁故障传播机理。近年来,关于复杂系统理论,特别是复杂网络理论的研究取得了重要进展。应用复杂系统理论为分析和研究大停电和连锁故障传播机理提供了一种新的视角,有助于从整体上掌握电力网络的复杂性,并讨论相应的动力学特性。主要从复杂网络、自组织临界性以及电网与通信网络的耦合关系这3个方面对近年来电力系统连锁故障建模以及电网脆弱性分析方面的研究进行综述,并展望相关重要研究课题与方向。     

基于连锁故障序列分析的电网脆弱性评估

电力系统的脆弱环节与连锁故障有着密切的联系,同时也是动态监测和控制的重要依据。为了有效地辨识出系统的脆弱环节,提出了基于不确定多属性决策理论的连锁故障搜索及电网脆弱性评估的新方法。首先,根据支路与支路保护之间的故障关系,建立了初始故障事件集,并计及各种引发连锁故障的因素形成实时条件下的决策矩阵,运用基于信息熵的多属性决策方法对初始故障事件进行排序,通过与设定的门槛值进行比较筛选出合适的初始故障事件;其次,基于改进的支路运行可靠性模型对后续故障进行搜索;最后,利用脆弱度函数对故障序列、节点及整个系统进行脆弱性评估。算例结果分析表明该方法具有良好的应用前景。     

大电网安全性评估的系统复杂性理论研究

在简述电力系统复杂性的基础上,介绍了系统复杂性理论在电力系统中的应用以及研究概况,包括电力系统的自组织临界性、电力系统连锁故障模型和复杂电力网络的结构脆弱性和连锁故障演化等,进一步指出电力系统复杂性理论的研究可能为探索互联电力网络的安全性和可靠性提供一个新的方向。     

信息网受损对电网过载主导型连锁故障的影响

信息网是实现信息系统功能的基础,信息网不同程度受损导致信息系统功能呈现多态性,影响电力系统的灾变应急能力。研究信息网受损对电网连锁故障的影响,是保证现代电网安全运行的重要课题。以信息系统的监视和控制功能为切入点,建立考虑信息网受损影响的电网连锁故障模型;结合信息网结构和信息系统功能受损程度量化指标,分析不同信息网受损程度对电网连锁故障的影响;从失效边群体区域分布和个体重要性角度,对比研究了几种信息边失效方式下,信息网受损对电网连锁故障的影响。对IEEE 30节点系统的仿真表明,信息网受损削弱了系统抑制电网连锁故障传播的能力,导致连锁故障蔓延;当电网处于重负载水平时,信息网受损对电网连锁故障的影响更为显著;不同信息边失效方式下电网连锁故障规模差异明显,信息网结构脆弱性是影响电网连锁故障传播的重要因素。     

基于Hadoop架构的电力系统连锁故障分布式计算技术

以提升大规模组合故障快速仿真分析能力为目标,在Hadoop框架下研发了连锁故障分布式计算技术。基于PSD-BPA软件计算模块,利用Java开发连锁故障计算分析功能,实现驱动判定、故障集筛选、事故链搜索、严重度评估4类模块。通过部署Hadoop分布式文件系统(HDFS)存储调度功能,将事故链解耦为小粒度单一故障场景进行计算,可针对连锁故障仿真的不同复杂度提供跨系统的分布式计算服务,灵活应对计算开始前连锁故障中事故链组合的不可预测性。利用10机、16机系统和某省网实际数据进行技术测试,结果表明所研发系统实现了连锁故障分析应用与数据在计算服务网络中的分离,具备动态调配计算节点资源的能力,能自动适应事件规模为电网连锁故障的仿真分析提供强大计算能力,具有在线应用前景。     

A new approach for mitigating blackout risk by blocking minimum critical distance relays

Electric power systems are complex and commonly run near their operational limits. Power systems are basically designed based on the (N − 1) criterion. In these systems, total or partial blackouts are unavoidable. Cascading failures following an initial event is recognized as the main mechanism for power system blackouts. Undesirable activation of zone 3 of distance relays due to their local function has been identified as one of the major causes for propagation of cascading failures. In this paper, in order to mitigate the risk of power system blackouts, a novel approach is proposed for recognizing the critical line outages with the highest contribution in cascading failure and preventing their undesirable outage by blocking zone 3 of their distance relay. In this paper, based on the statistical activation of distance relays, a deterministic–probabilistic approach is developed for identifying the critical lines with the highest contribution in blackouts due to activation of zone 3 of their distance relays. In order to avoid interference of relay blocking with the main protection duty of distance relays, the proposed approach recognizes the minimum critical lines with the highest contribution in cascading failure for blocking zone 3 of their distance relays. The proposed approach is demonstrated on the New England 39-bus system and detailed simulation studies carried out to examine the validity and effectiveness of the proposed approach.     

基于线路运行可靠性模型的电力系统连锁故障概率评估

线路过载被认为是致使连锁故障进一步发展的主要原因.文中基于输电线路的运行可靠性模型,计算了反映系统运行状态的连锁故障风险指标.采用递归算法生成连锁故障树,记录连锁故障路径经历的每个状态及其相应的连锁故障风险指标.在运行可靠性评估框架的基础上,结合动态潮流计算,对IEEE RTS系统进行了连锁故障运行可靠性评估.分析了不...