新原理的中,低压线路,母线保护装置的研制

提出并研制了新型的线路定时限电流保护，这种保护不单单依靠上下级保护间定值和时限的配合，更重要是依靠电压波形和各级保护间的动作逻辑的配合，保证选择性。新型的母线保护不需要对母线上所有开关电流进行波形比较和向量综合，它只需要采集电源开关的电流和馈线开关保护的动作信号及母线电压波形，当母线故障时瞬时切除故障母线，当馈线故障开关拒动时，母线保护还具有延时切除电源进线开关的后备保护或失灵保护的作用。     

新原理的中、低压线路、母线保护装置的研制

提出并研制了新型的线路定时限电流保护，这种保护不单单依靠上下级保护间定值和时限的配合，更重要是依靠电压波形和各级保护间的动作逻辑的配合，保证选择性。新型的母线保护不需要对母线上所有开关电流进行波形比较和向量综合，它只需要采集电源开关的电流和馈线开关保护的动作信号及母线电压波形，当母线故障时瞬时切除故障母线，当馈线故障开关拒动时，母线保护还具有延时切除电源进线开关的后备保护或失灵保护的作用。     

变电站11＼2接线中母线电压互感器缺省的设计及研究

在１１／２主接线的变电站中,当母线保护不采用母线电压信号时,提出了不设母线电压互感器,可节省两套母线电压互感器及其避雷器,如果需要母线电压测量值,则可通过可编程控制器控制的切换开关来实现,取自于与母线相联的进出线或变压器的电压互感器二次回路。     

电压暂变补偿新拓扑的母线电压控制策略研究

针对一种无整流器无变压器无储能电容的串联型电压暂变补偿新拓扑,为了使其上、下母线电压保持平衡,且使母线电压保持恒定,深入研究了其母线电压控制策略。首先讨论了负载电压波形跟踪控制,上、下母线电压平衡控制,和母线电压幅值控制3个闭环带宽之间的关系;然后改进了上、下母线电压平衡控制的闭环系统设计;对于母线电压幅值控制闭环系统的非线性被控对象,研究并得出了其微变小信号线性化模型,并给出了母线电压幅值控制的闭环系统设计方法。最终给出了1套完整的设计方案。仿真结果验证了理论分析和系统设计的正确性。     

小电阻接地系统馈线自适应零序电流保护原理及装置实现

小电阻接地系统发生多回线同相复杂接地故障时,零序电流幅值相比于单回线接地故障将显著下降,容易导致馈线首端的零序电流保护拒动,进而造成母线接地变压器的零序电流保护越级误动,扩大停电范围。为此,对小电阻接地系统多回线复杂接地故障的故障机理进行分析,推导了多回线与单回线接地故障下馈线零序电流关系;在此基础上,提出了一种自适应馈线零序电流保护方案,即根据母线电压将多回线接地故障的零序电流实时补偿为单回线接地故障的零序电流值,从而确保了常规的保护动作值整定方式和保护配合能够适用于多回线复杂接地故障,并研发了相应的自适应零序保护装置。基于PSCAD/EMTDC和RTDS对保护原理及保护装置的测试结果表明,自适应零序电流保护在多回线复杂接地故障情况下仍具有较高的灵敏性,补偿精度不受过渡电阻、故障位置的影响。所提保护方案只需在原有零序电流保护方案基础上,增加母线电压信息,容易实现,具有经济性和较高的工程应用价值。     

关于PMH—87EY—S屏三相式双母线相位比较差动保护在保护传动试验过程中...

本文对母差保护在传动试验过程中，模拟Ｉ母故障时，Ⅱ母出口信号继电器ＸＪⅡ误动作；而当模拟Ⅱ母故障时，Ｉ母出口信号继电器ＸＪⅠ误动作；提出了改进意见仅供大家参考。     

一起220kV双母线全停故障分析

某变电站220k V系统采用双母接线方式并配置母线电压互感器(TV)。在220k VⅠ母TV因故停用的情况下,Ⅱ母上一条线路因线路电流互感器(TA)着火,致使两条母线上所连线路断路器全部跳开,造成Ⅰ、Ⅱ母全停事故。对上述故障过程及原因进行了剖析,建议今后双母线接线,宜按照保护"六统一"要求,使用线路TV。对于已使用母线TV的变电站,当一条母线的TV停用时,应做好双母全停的事故预想。     

旁路母线开关增设二次电压切换装置

我国110kV 及以上电压等级的大、中型降压变电所主接线多采用双母线带旁路母线的接线方式,而典型设计旁路开关保护屏配备是按线路保护选择设计的,没有考虑旁路开关代替主变总路开关运行时的二次电压切换装置和装设旁路母线电压互感器。为此,对主变的安全运行制造了不安全死区,一旦     

金昌,嘉峪关变330kV母线电压越限运行与系统运行方式关系的探讨

甘肃电网３３０ｋＶ海（石湾）－金（昌）－嘉（峪关）线路全长６５５．９３４ｋｍ，该线路具有典型的长线带弱网的运行方式，投运以来，金昌，嘉峪关变３３０ｋＶ母线电压越限运行问题突出，文章对金昌，嘉峪关变３３０ｋＶ，母线电压与甘肃主网电压，海－金－嘉线的潮流分布及金昌，嘉肉关变无功负荷变化等关系进行了计算研究，对电网运行有一定的指导意义。     

上海电网35kV母差保护选型的探讨

通过对35 kV BCH-2母差保护误动原因及电流互感器特性的分析,结合大电流试验结果,对上海电网35 kV母差保护选型作了探讨,认为具有制动特性的BCH-1和7UT51型系列继电器可代替原BCH-2继电器,并可作为35 kV母差保护的首选差动继电器.     

小电流接地故障暂态方向保护原理研究

分析了小电流接地系统接地故障暂态零序电压电流特征。根据线路的相频特性将频率分为不同区段，论证了在一选定的低频区段内，所有健全线路分别可用一集中电容等效；在该选定频段内，故障线路暂态零序电流或无功功率方向与非故障线路相反。据此提出了检测暂态零序容性电流或无功功率方向的暂态方向保护算法。该方法灵敏度、可靠性高，不受消弧线圈和不稳定电弧的影响。实际故障数据验证了该方法的正确性。     

茂名热电厂110 kV系统小网运行分析及应对措施

茂名热电厂1号机组改造后,由于容量的增加而暴露了110 kV系统的薄弱性,母联断路器及系统联络变压器两侧断路器跳闸均会造成110 kV系统小网运行,影响供电安全。通过采取装设有小网运行和超速保护(OPC)功能的数字电液(DEH)控制系统、装设电超速保护及机械超速保护、装设高频切机保护等措施,可提高电网运行可靠性,改善电压质量,确保电网安全运行。     

Overcurrent protection for distribution feeders with renewable generation

Distribution systems in Taiwan are typically radial type or normally open loop type. Distribution feeders have a simple protection system that usually employs overcurrent relays. When renewable generation (RG) is connected to the distribution feeder, the feeder changes from a single-source system to a complex multi-source system, which causes loss of the original coordination among feeder protection devices. The operation of RG units can cause protection failure. Fault current produced by RG units may reduce the current measured by the feeder relay. Therefore, this paper proposes connecting RGs to the feeder via four-way circuit switches with overcurrent relays, and dividing the feeder into several protection zones. Each protection zone is capable of isolating fault itself.The algorithm process and design procedure of overcurrent protection are also proposed for distribution feeders with RG. Results of this research provide a valuable reference for overcurrent protection that improved protection coordination and system reliability.     

A selective single-phase-to-ground fault protection for neutral un-effectively grounded systems

Single-phase-to-ground faults are the most frequent faults likely to occur in power distribution networks. As for a neutral un-effectively grounded system (NUGS), the low fault current is very common in the case of occurrence of a single-phase earth fault, leading to hard identification of the faulty feeder. In conventional way, this target can be possibly achieved by the comparison of the polarities, magnitudes, or the phase angles of the zero-sequence currents of all feeders connected to the same busbar. However, it becomes a difficult task to implement this functionality into the protection of feeder. In this paper, a novel single-phase-to-ground fault protection for NUGS is put forward. Different from conventional centralized-comparison protection, this protection can detect single-phase-to-ground fault on the feeder individually, and can be realized on FTU (Feeder Terminal Unit). It is based on the measurement of the zero-sequence voltage and zero-sequence current. The tripping strategy follows the characteristic of the modified inverse-time delay curve. By means of analyzing the characteristics of the zero-sequence transient currents, it is disclosed that the magnitude of the zero-sequence current of the faulty feeder should be greater than that of any sound feeder. Then a composite compensated voltage is formed based on the zero-sequence voltage and zero-sequence current to evaluate a revising factor for every feeder respectively. Using this revising factor to modify the identical standard inverse-time delay curve adopted by all the feeder zero-sequence overvoltage protections, the tripping time of the zero-sequence overvoltage protections of all feeders will differ from each other. In this case, the selectivity of the protection can be guaranteed. This proposed algorithm is validated with the EMTP simulation tests.     

一起地铁供电系统停电事故的分析及对策

地铁供电系统中的母联闪络是一种具有一定隐蔽性的严重故障,会导致主变电所的停电和地铁线路的大面积停运。结合一起地铁供电系统停电事故,分析了母联闪络故障的产生机制和闪络故障时系统中零序过流保护大面积误动作的原因,并提出了改进措施。     

一起CT饱和引起越级跳闸的故障分析

某110kV变电站中一条35kV线路发生永久性故障,保护装置在第一次正确动作并重合后,未再次正确动作,造成主变保护越级跳闸,并最终导致35kV母线失压。文中深入探讨了保护拒动的原因,阐述了事故检查处理过程,对保护装置在运行过程中暴露出的弱点进行了系统的分析,并对此提出具体解决方案。     

行波小波系数极大值极性法接地故障选线研究

为正确确定故障线路,保证系统安全,提高供电可靠性,研究了配电网中单相接地短路故障时的暂态行波特性。分析变压器的暂态行波特性及其对母线行波电压和线路行波电流的影响表明,行波初始过程中母线电压及各线路电流暂态行波的小波系数的显著规律是故障线路电流暂态行波0模量初始波头的小波系数的极大值极性,总是与其它线路电流和母线电压相反。然后利用暂态行波的小波系数极大值极性特征构成了一种新颖的故障选线保护判据,即利用母线零序电压突变量判断单相接地的时刻,通过识别母线电压及各线路电流初始波头小波系数的极大值极性特征,判断故障线路。利用MATLAB建立了一个典型的配电网系统模型,仿真结果证明该选线算法的有效性,最后对该法的应用提出相关的建议。     

基于多源数据的馈线谐波频谱估计方法

随着分布式电源和非线性负荷的投运规模不断增加,电网谐波污染愈加严重和复杂,有必要对各馈线谐波电流进行监测。但基于经济性考虑,对变电站所有馈线均进行谐波电流监测并不可行。针对上述问题,提出了基于多源数据的馈线谐波频谱估计方法。该方法基于电网现有电能质量监测系统、调度系统、营销业务应用系统等多源数据,只需对母线谐波电压和进线谐波电流开展监测,即可估计出变电站所有馈线的谐波电流情况。首先,根据馈线谐波电流的相量运算关系和功率关系构建馈线谐波频谱估计的目标函数。其次,基于多源数据利用改进粒子群算法求解目标函数,进而得到各馈线的各次谐波电流含有率及馈线谐波电流间的相角差,实现了各馈线谐波电流频谱的估计。最后,通过仿真算例和实测算例验证了方法的可行性。算例表明该方法仅需在变电站母线处安装一台电能质量监测终端,结合现有业务系统的基本电气数据等信息,可实现馈线谐波频谱的估计,有助于节约变电站监测装置的配置成本。     

Feasibility study of upgrading primary feeders from radial and open-loop to normally closed-loop arrangement

The feasibility study of upgrading primary feeders from radial and open loop to a normally closed-loop arrangement have been explored in this paper. First, three possible feeder arrangements for forming a normally closed loop are discussed, and then the factors that may predominantly affect the system-type upgrading are discussed theoretically. Next, four existing distribution feeders with original radial arrangements, fed by three power transformers that are located at two different distribution substations of Taiwan Power Company (Taipower) are employed as sample systems. To form three types of closed-loop arrangement, all of the four radial feeders were tied together at their ends, two feeders at a time. The power flows, voltage profiles and short-circuit capacities of the feeders under both the tie breaker normally open and closed cases have been evaluated, and the impacts of the upgrading of system type on the distribution system and customers assessed. Finally, the required supporting measures for these kinds of upgrading have been listed, and the most suitable and feasible arrangement was recommended to Taipower.     

小电阻接地配电网多回线故障分析与自适应零序电流保护

当小电阻接地配电网发生同母多回线接地故障时,每条馈线的零序电流相比于单回线故障时有较大差别,馈线零序电流保护可能不正确动作。为此,首先推导了发生多回线同名相单相接地与单回线单相接地故障时馈线零序电流间的关系,揭示了保护不正确动作机理。提出了考虑负荷且能适用于不同类型多回线接地故障的零序电流计算方法。基于实际变电站参数搭建RTDS仿真模型,分析了不同类型多回线接地故障对零序电流保护的影响。在此基础上,提出了自适应馈线零序电流保护方案,利用故障前电压等参数将发生多回线接地故障时的零序电流修正为发生单回线接地故障时的零序电流,在不改变原有保护定值的情况下使零序电流保护能够自主适应于不同类型的多回线接地故障。基于RTDS和自主研发的保护测控装置的测试结果表明,所提保护方案不受负荷电流的影响,能够在不同类型的多回线接地故障发生时正确动作,且能够提高馈线零序电流保护对过渡电阻的耐受能力。