基于故障暂态和数学形态学的超高速线路方向保护

引入数学形态学以提高基于故障暂态的超高速线路方向保护的动作性能。在获取连接在同一母线上的各条输电线路暂态电流信号的基础上，采用数学形态学分析其极性和能量以确定故障方向。仿真结果证明，该方法适用于识别发生在输电线路不同位置的各种故障。该方案对处理器的采样率、处理能力和速度几乎没有额外的要求，具有很好的实用性。与传统保护算法相比，基于MG的TBDP具有更高的可靠性和较少的计算量，同时具有更快的故障响应能力和更高的灵敏性。     

A new non-communication protection technique for transmission lines

This paper proposes a new noncommunication protection technique for transmission line protection. The technique relies on firstly the detection of fault generated high frequency current transient signals. A specially designed multi-channel filter unit is then applied to the captured signals to extract desired bands of high frequency signals. Comparison between the spectral energies of different bands of the filter outputs determines whether a fault is internal or external to the protected zone. In addition to the saving in costs through negating the need for a communication link, the technique also retains many advantages of the `transient based protection' technology, such as insensitivity to fault type, fault position, fault path resistance and fault inception angle. It is also not affected by CT saturation, the power frequency short-circuit level at the terminating busbar or the precise configuration of the source side networks     

Fast isolation of faults in transmission systems using current transients

This paper presents a protection scheme that is capable of very fast isolation of faults in high voltage transmission systems. Proposed scheme comprises set of relays connected through a telecommunication network, located at different nodes of the system. Relays use wavelet coefficients of current signals to identify the fault directions relative to their location. Fault directions identified at different locations in the system can be combined to determine the faulted line (or busbar) and isolate it. A robust single ended traveling wave based fault distance estimation approach is proposed as a backup in case of communication failure. Investigations were carried out using time domain simulations in PSCAD/EMTDC for a high voltage transmission system.     

电力系统的集成保护

通过介绍一种新颖的配电网保护方案来阐述集成保护的优越性。这个基于暂态极性方向比较的保护方案以伴随故障出现的暂态电流信号的检测和处理为基础,在配电网的各个变电站安装有专门设计的保护继电器,继电器的暂态检测单元检测故障生成的故障分量电信号,并将暂态极性识别算法应用于叠加故障分量信号上,判断信号的极性。通过对来自连接到变电站的所有线路的信号极性进行比较,可以确定出故障的方向。通过处理来自各变电站的方向信息,判别出实际的故障线路,从而实现电网的集成保护。     

A new PMU based power swing detector to prevent mal-operation of distance relay

In conventional transmission line protection, a distance relay is used to provide the primary as well as remote backup protection. The voltage and current phasors measurement needed by the distance relay for determining the impedance may be affected by the power disturbances such as power swing. Consequently, this power swing may cause mal-operation of Zone three distance relays which in turn may affect on the reliability of the whole protective scheme. To mitigate these effects and hence improve the relay reliability, this work proposes a new real-time power swing detector using phasor measurement units for blinding the distance relay only during this transient disturbance. However, this developed detector will not block relay when the power swing accompanied with faults. To validate the present work, the performance of developed enhanced distance relay is tested by signals generated by Simulink/MATLAB simulator under different conditions. The test results show that this proposed scheme provides good discrimination between the transient currents and the fault current which in turn it may contribute in enhancing the reliability of Distance relay.     

Positional protection of transmission line using fault generatedhigh frequency transient signals

This paper presents a new technique for high-speed protection of transmission lines, the positional protection technique. The technique uses a fault transient detector unit at the relaying point to capture fault generated high frequency transient signals contained in the primary currents. The decision to trip is based on the relative arrival times of these high frequency components as they propagate through the system. Extensive simulation studies of technique were carried out to examine the response to different power system and fault conditions. Results show that the scheme is insensitive to fault type, fault resistance, fault inception angle and system source configuration, and that it is able to offer both very high accuracy and speed in fault detection     

基于电弧复小波检测的单相自适应重合闸

提出一种单相自适应重合闸的新方案。该方案利用复小波分析来检测电弧产生的谐波,并以此区分输电线路的单相瞬时性故障和永久性故障。故障发生后,对于不同的故障性质,线路首端重合闸安装处的电压谐波含量是不同的。根据电压谐波含量的特征,提出利用复小波相位和幅值的新算法综合判别来快速确定线路的故障性质。该方法可以在熄弧之前进行判断,保障了最佳重合时间。线路故障仿真验证了该算法的有效性和实用性。     

A novel non-unit protection for series compensated EHV transmissionlines based on fault generated high frequency voltage signals

A new high-speed protection technique based on fault generated high frequency (HF) voltage signals is developed and applied to the protection of EHV series compensated power transmission lines. It is a nonunit protection technique as it relies totally on locally derived information, but it has the discriminative properties normally associated with unit protection schemes. The protection scheme has been designed using CAD techniques including emulation of analogue interfaces and hardware. It is shown that the new relay scheme is able to overcome many difficult protection problems encountered on such EHV power lines using conventional methods, and discriminates clearly between internal and external faults, producing a fast trip output     

Development and Investigation of a New High-Speed Directional Relay Using Field Data

In this paper, a new high-speed directional relay is proposed. The relay is based on the current and voltage signals before and after fault occurrence. The voltage signal is compensated and then used as a reference. The relay is used for the directional comparison protection of extremely high voltage transmission lines. An evaluation of the suggested directional relay is investigated using recorded fault data from the Alberta power transmission system. The real effects of the power system elements, which might have not been completely considered in the mathematical model of the power system, have been included in the recorded real fault data. In this case, the performance of the new directional relay can be verified in a more realistic environment than simulation.     

DYNA-TEST simulator for relay testing. I. Design characteristics

The authors describe a new digital dynamic testing (DYNA-TEST) simulator developed for protection relay applications. This simulator is capable of producing voltage and current transients that correspond to actual fault events in the power systems. Fault transients are generated either by simulating power system faults using an electromagnetic transient program or by replaying records of fault signals captured in substations by digital fault recorders. These signals are used to test protection relays. Such an approach to relay testing represents a major improvement over steady-state testing     

Transient positional protection of transmission lines using complex wavelets analysis

This paper presents a new high-speed protection scheme, transient positional protection (TPP), for power transmission lines. This scheme is developed using complex wavelet analysis, based on the concept of transient-based protection (TBP), in which the fault-generated high-frequency transient signals contained in the primary voltages are utilized to detect fault position according to their relative travelling time and polarities. Combined information (CI) is obtained from complex wavelet coefficients to extract and localize a band of specified high-frequency components propagating along the transmission line. A typical 400 kV extremely high voltage (EHV) transmission system has been simulated by PSCAD/EMTDC to evaluate the scheme. The simulation results show that this scheme is capable of providing correct responses under various system configurations and fault conditions.     

A hybrid algorithm for high speed transmission line protection

A common method used in UHV transmission line protection is based on impedance measurement technique. The fault detection speed of impedance protection schemes cannot be improved without sacrificing the relay reach limit. Protection algorithms based on fault generated transient signals have shown promising results in improving the speed, but these methods have inherent reliability problems. This paper examines how the fault generated transient information can be used to achieve fast fault detection speeds in a distance protection scheme while maintaining a high reliability level.     

分布式电源多点接入配电系统的集成保护

针对分布式电源多点接入的配电系统,提出了一种基于暂态极性保护原理的集成保护新方案。暂态极性比较保护是运用小波变换提取故障暂态高频信号的某一频段信息作为故障判断的依据,通过比较暂态高频信号的极性,迅速准确判断出故障位置。将暂态极性比较保护原理应用于配电网集成保护方案中,以母线作为载体构建集成保护单元,利用本地故障信息和相邻保护单元故障信息对母线各出线以及线路两端信号的极性进行比较,从而对母线故障和线路故障进行判断。与此同时,集成网络保护单元提取多点信息,对整体区域暂态信号极性进行综合比较,实现对故障的快速定位与隔离,为本地保护提供后备保护。最后,利用MATLAB软件对其进行了仿真分析,仿真结果验证了此保护方案的正确性和可行性。     

基于暂态能量的输电线路速动保护方案

利用母线杂散电容吸收高频分量的特点,构成了能准确区分区内、区外故障的速动保护方案。对输电线路保护安装处的电压、电流进行模量转换得到模量电压和模量电流,并将模量电压和电流进行Daubechies 4小波变换得到所需频段的低频信息和高频信息,利用这些信息计算得到相应频段的频谱能量,然后得到模量电压和模量电流的暂态特征,将电压和电流的暂态特征综合起来得到故障后的暂态能量,该暂态能量可用来识别故障位置。该保护方案的灵敏度不受过渡电阻、雷击、故障类型、负荷电流、系统运行方式等因素的影响。此外,由于保护的数据窗很短,电压互感器、电流互感器的传变特性对保护的性能没有影响。     

Adaptive relay co-ordination using a busbar splitting approach for a system integrity protection scheme

Power system faults can often result in excessively high currents. If sustained for a long time, such high currents can damage system equipment. Thus, it is desirable to operate the relays in the minimum possible time. In this paper, a busbar splitting approach is used for adaptive relay setting and co-ordination purposes for a system integrity protection scheme (SIPS). Whenever a fault occurs, the busbar splitting scheme splits a bus to convert a loop into a radial structure. The splitting schemes are chosen such that the net fault current is also reduced. Busbar splitting eliminates the dependency upon minimum breakpoints set (MBPS) and reduces the relay operating time, thus making it adaptive. The proposed methodology is incorporated into the IEEE 14-bus and IEEE 30-bus systems with single and multiple fault conditions. The modeling and simulation carried out in ETAP, and the results of the proposed busbar splitting-based relay co-ordination are compared with the MBPS splitting-based relay co-ordination.     

一起500 kV接地故障暂态特征和继电保护动作行为分析

介绍了在复杂电网中,一起500 kV超高压长输电线路永久性单相接地故障后暂态过程,结合继电保护动作报告及故障录波图,分析并推断了故障的发展过程,从谐波含量、各序分量和三相电压不平衡度等角度分析了故障发生后至故障点未切除前系统的电能质量,对继电保护装置在故障情况下的动作正确性进行了详尽的分析,对其防范措施进行了探讨。     

快速工频量高频方向保护的新方案

本文针对相电压补偿方向元件的不足,提出了两种新型的方向元件－－负序电压补偿式方向元件和相电压故障分量补偿方向元件,通过大量的ＥＭＴＰ仿真验证了其优良性能,并在此基础上,提出了实现快速工频量高频方向保护的新方案,即：对于各种不对称故障采用负序电压补偿式方向元件,对于三相故障采用相电压故障分量补偿式方向元件,对于非全相状态下的故障采用和电压补偿式方向元件。     

一种适用于中低压短线路的光纤纵差保护方案

分析了中低压短线路纵差保护的现状,对电流综合量继电器与普通电流继电器在各种短路情况下的灵敏度比较,复式比率差动继电器与常规比率差动继电器在各种短路电流情况下的动作性能比较等进行了研究。提出了一种适用于中低压短线路的复式比率电流综合量差动保护原理方案。此方案可提高保护的灵敏度,同时为光纤纵差保护采用异步通信方式提供可能,达到降低保护装置成本的目的。     

利用单端暂态量实现超高压输电线路 全线速动保护新原理研究（一）——故障暂态过程分析及实现单端暂态量保护的可行性

在综述暂态量保护特别是反应是单端暂态量的超高压输电线路全线速动保护的基础上,利用输电线路的波传导方程分析了故障暂态过程是由于故障点行波在输电线路上多次折、反射的叠加而形成。母线的杂散电容和阻波器等的存在,使得区内、外故障产生的暂态分量有差异,这种差异主要表现在暂态电压、电流波形的高频分量部分。利用DSP硬件手段和小波分析的数学工具,可以构成单端暂态量保护,实现全线速动。     

±500kV直流输电线路暂态故障监测装置的设计与应用

高压直流输电系统因暂态过程导致故障或停运时,目前所采用的录波仪只能记录极线电压和电流,无法提供相关的高频故障波形信息以实现故障的快速识别,不利于迅速排除故障和恢复送电。为了监测直流输电线路上的高频暂态故障行波和雷电侵入波,文中研制了可直接安装于±500kV直流导线上的暂态故障监测装置,设计了适用于直流线路的新型供电系统、高频传感器、数据采集与传输单元等,并进行了现场应用,监测到的雷电波形数据与雷电定位系统进行对比后验证了装置的有效性和可靠性,可为直流输电系统暂态故障的监测、识别和复现提供技术手段。