串补电容对工频变化量距离保护的影响

详细分析了有串补电容线路上工频变化量距离继电器的性能,得出工频变化量距离继电器应用于串补线路在不计暂态过程能够正确动作,而在计入暂态过程时可能存在暂态超越。在此基础上提出了防止暂态超越的措施－－提高动作门槛。EMTP仿真程序结合保护仿真程序验证了上述理论分析的正确性和防止暂态超越方案的有效性。     

一种新的比相式电抗型距离继电器算法

对测量阻抗型和相量比较型两种类型的电抗距离继电器的抗稳态超越的能力进行了研究,主要包括负荷的影响和同相问题的研究。同时,构造了一个新的电抗型距离继电器判据和算法,该算法具有方向性,且不受负荷和同相问题的影响,解决了由于负荷和同相问题引起的稳态超越现象,提高了保护动作的可靠性。电磁暂态仿真结果证明该原理具有防止负荷和同相问题引起的稳态超越和保护范围不足的问题。     

一种新的比相式电抗型距离继电器算法

对测量阻抗型和相量比较型两种类型的电抗距离继电器的抗稳态超越的能力进行了研究,主要包括负荷的影响和同相问题的研究.同时,构造了一个新的电抗型距离继电器判据和算法,该算法具有方向性,且不受负荷和同相问题的影响,解决了由于负荷和同相问题引起的稳态超越现象,提高了保护动作的可靠性.电磁暂态仿真结果证明该原理具有防止负荷和同相问题引起的稳态超越和保护范围不足的问题.     

降低多相补偿距离继电器暂态超越的措施

目前国内不少单位研制并推出利用多相补偿原理实现的距离继电器。此原理不但简化了保护回路,而且还提高了保护性能。但仍有其不足之处,即易出现较大的暂态超越。由于利用整流型原理和半导体元件实现多相补偿距离继电器,其结构必然复杂,而且调试和使用均不够方便。因此,本保护采用集成电路,进一步简化了距离继电器的结线回路,也有利于整定、调整、使用和获得较好性能。     

自适应接地距离继电器的研究

接地距离继电器要解决的关键问题之一是提高其耐受过渡电阻的能力。在分析自适应接地距离继电器动作特性的基础上,提出了对自适应动作特性的修正方法,从而使修正后的自适应接地距离继电器既有很强的抗过渡电阻能力,又能有效地防止暂态超越。仿真结果证实了这种继电器具有良好的自适应性和选择性。     

利用二次函数修正微分方程不平衡量的距离保护算法

暂态超越现象的存在,使得距离保护Ⅰ段的作用受到很大限制,保护范围大大缩小,在高压电网甚至超高压电网中,暂态超越现象尤其严重。文中利用二次函数对微分方程中由于互感器特性不一致引起的不平衡量进行修正,能够防止距离保护的暂态超越现象,使得距离保护的动作速度显著提高,保护动作特性明显改善。通过动模数据和实际现场保护录波数据对算法进行仿真验证,结果表明所提出的算法能够明显改善距离保护Ⅰ段的保护性能,有效防止暂态超越。     

自适应接地距离继电器的探讨

接地距离继电器要解决的关键问题之一是提高其耐受过渡电阻的能力。在对自适应接地距离继电器动作特性进行分析的基础上,提出了对自适应动作特性的修正方法,从而使修正后的自适应接地距离继电器既具有很强的抗过渡电阻能力,又能有效地防止暂态超越。仿真结果证明了这种继电器具有良好的自适应性和选择性。     

工频变化量距离保护校验研究

电力系统继电保护按原理上可划分为反应稳态量的保护和反应暂态量的保护,反应暂态量的工频变化量的阻抗继电器和工频变化量的方向继电器的理论准确度高、速度快,具有较好的动作性能。本文分析了工频变化量距离保护的基本原理及调试方法,为工频变化量距离保护的定值整定、功能校验、动作分析提供参考。     

一种能克服_0极化接地距离继电器区外稳态超越问题的新方案

本文针对改进的　０极化接地距离继电器中存在的稳态超越问题，提出了一种新方案──双下偏　０极化接地距离保护方案。采用这种方案，能有效地解决改进的　０极化接地距离保护中存在的区外稳态超越问题而不影响保护耐受过渡电阻的能力。仿真计算的结果表明该方案在理论上是正确的，且易于在微机距离保护装置中加以实现。     

一种能克服I0极化接地距离继电器区外稳态超越问题的新方案

本文针对改进的Ｉ０极化接地距离继电器中存在的稳态超越问题，提出了一种新方案－双下偏Ｉ０极化接地距离保护方案，采用这种方案，能有效地解决改进的Ｉ０极化接地距离保护中存在的区外稳态超越问题而不影响保护耐受过滤电阻的能力，仿真计算的结果表明该方案在理论上是正确的，且易于在微机距离保护装置中加以实现。     

Under-Reach Correction in Twin Circuits Without Residual Current Input From the Parallel Line

Mutual coupling poses difficult problems witnessed during single phase to earth fault, in transmission line protection. In parallel lines on the same right of way, mutually coupled zero-sequence circuits cause error in the apparent impedance seen by the relay. This causes the distance relay at one end of the faulty line to over-reach while the one at the other end to under-reach. Incorrect sensing of the ground fault due to zero-sequence voltage inversion caused by mutually coupled zero-sequence network may lead to false trip of the neighbouring healthy line. The paper develops characteristic expressions for effective sequence impedances of twin circuit lines and presents a non-iterative microprocessor based algorithm for fault distance and under-reach estimation in real time, for under-reach correction in basic distance relaying scheme. The residual current measurement from the parallel circuit is not required for this purpose.      

配电网单相接地保护的研究

为快速识别配电网单相接地故障,断开故障线路并发出故障跳闸信号,仿真分析了配电网单相接地故障时故障线路和正常线路的暂态零序功率的特点,应用小波包精细分析配电网单相接地故障后的暂态零序功率,提取反映故障线路的暂态零序功率特征频带和信号窗长度;以零序电压作为单相接地保护的启动条件,以线路在特征频带和固定时间窗口的暂态零序能量为保护动作判据,构成配电网单相接地的反时限保护。仿真分析表明该单相接地保护动作原理不受短路时刻、接地电弧电阻、线路长度等因素的影响,满足继电保护"四性"要求。     

An adaptive approach for three zone operation of digital distance relay with Static Var Compensator using PMU

Modern energy transmission systems suffer from great voltage dropping due to enormous loads. Therefore appropriate schemes should be devised to regulate the voltage. FACTS devices such as Static Var Compensator are often used for this purpose. However, SVC at mid-point of transmission line may leads to deteriorate of distance relay operation, resulting in inaccurate estimation of faults locations i.e. over-reach or under reach for different cases. This paper proposed a new algorithm that utilizes synchronized phasors measurement (SPM) to enhance the operation of distance protection zone in many aspects. The proposed method is tested for 230 kV system simulated in EMTDC/PSCAD with Bergeron model of transmission line. The results prevailed for adaptive approach scheme are more accurate, victor and robust in equivalence with usable transmission line distance protection with SVC.     

阻抗继电器与距离继电器分类的补充说明

给出阻抗继电器与距离继电器新的定义。进一步阐明了阻抗继电器与距离继电器的特点。说明了阻抗继电器是建立在测量阻抗概念上的一类继电器 ;距离继电器是建立在补偿电压特点基础上的一类继电器。规定了测量阻抗动作特性和支接阻抗动作特性的适用范围。提出了阻抗继电器的两条性质 ,并给出这两条性质的应用实例。最后对距离继电器的进一步发展给予展望     

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.     

Stochastic analysis of fault-induced transients for distance relaying application

It is well known that the operation of distance relays relies on the power frequency components to calculate the fault impedance and hence make decision on tripping. It is also discovered that the transient induced during fault has a significant effect on the performance of distance protection, especially on that of the high-speed protection. A better understanding on fault transient can lead to a better relay design and better performance in terms of speed and relay reach. This paper analyzes the fault transients in EHV transmission lines by using time-domain stochastic techniques. Major emphasis are placed in the investigation into the differences between the fault transient attributes of different fault types and the transient features of the composite signals used in distance relay, such as the phase-to-phase quantities. This investigation leads to the development of adaptive approaches that can be implemented in digital distance relays in order to achieve an improved relay performance.     

Digital distance protection of transmission lines

Experience with a digital distance relay algorithm, which also utilizes a digital low-pass filter, is presented. It is shown that the relay is capable of tracking the apparent impedance of a transmission line, as it experiences a short circuit, with a speed and accuracy which are competitive with existing distance relay hardware. The distance relay algorithm is feasible with current large-scale integration technology, although a specific micro-processor architecture has not yet been directed to this particular application.     

基于暂态相控大电流的继电保护无负荷相量测量方法

针对一次设备带负荷前继电保护设备无法开展带实际负荷验证保护方向问题,提出一种基于暂态相控大电流的继电保护无负荷相量测量方法。注入电流互感器一次暂态大电流相位与参考电压保持固定角度,在电流互感器二次回路及继电保护装置回路中以录波方式测量参考电压与电流互感器变换后的暂态电流相位是否仍然保持固定角度,确定带方向保护功能的正确性,实现电流互感器极性、电流互感器二次回路注流、带负荷相量测量三项试验在设备正式带电前一次完成。     

基于阻抗比较的同杆并架选相新方法

首先对综合比相阻抗继电器在同杆并架双回线故障下的动作行为进行了研究,在此基础上提出一种结合综合比相继电器的选相新方法。这种选相元件根据改进后的综合比相继电器的选相结果,参考测量阻抗值对已选出的动作相再次进行筛选。同杆并架的后备距离保护应用此选相元件,通过适当的整定配合,能可靠地区分靠近线路末端跨线故障和区内相间故障,提高距离保护I段的正确动作率。数字仿真结果表明,基于阻抗比较的同杆并架选相新方法受同杆并架线路拓扑结构和对称性等因素影响小,能保证后备距离保护I段在各种线路运行方式下正确选相跳闸。     

短线路两相短路时距离保护误差分析

距离保护在高压及超高压输电线路得到广泛应用,随着国内电网建设的加强,高压输电线路的长度越来越短,特别是城市电网中,短线路不断增多,但是短线路在两相短路时,由于测量电压的误差会放大,可能引起距离保护的超越。推导了短线路两相短路时电压测量误差的计算公式,分析了该误差对距离保护的影响。