A Current Differential Relay for a 1000-kV UHV Transmission Line

This paper describes the principle of a new current differential relay developed for a 1000-kV UHV transmission line that is being constructed in China. The distributed capacitive current along the relatively long overhead line will have a significant effect on the relay performance and should be taken into account in the relay principle. The study results in a new current differential relay based on the steady state transmission line equations, in which the distributed capacitive current is inherently represented. Analysis is carried out for different practical situations where shunt reactors or series capacitors are present in the system for compensation. Laboratory tests show that the relay principle developed in this study can be used as a main protection scheme for the 1000-kV UHV transmission line.     

基于分布参数模型的特离压双回线路故障分量接地距离保护

特高压交流同杆双回输电线路分布电容大、传输距离远,呈显著的分布参数特性,传统距离元件应用于特高压双回线路时存在原理性缺陷。基于分布参数模型和六序分量法,理论分析和推导了新的特高压双回线路单相接地距离元件测量阻抗的计算表达式,并且应用到故障分量距离继电器中。EMTP仿真验证了新的距离保护算法在特高压双回长线路上应用的正确性与有效性。     

特高压长线路距离保护算法改进

特高压长距离输电线路呈显著的分布参数特性,其电容电流很大。分析表明,线路末端三相故障时,线路首端的测量阻抗不与故障距离成正比。研究指出,相间距离保护的测量阻抗与故障距离呈双曲正切函数关系,而传统接地距离保护应用于特高压长线路时存在原理性缺陷。理论分析并推导了新的接地距离元件测量阻抗的计算表达式,并提出了距离保护的改进措施,大量仿真证明了改进措施在特高压长线路上应用的正确性与有效性。     

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.     

特高压交流输电线路接地阻抗继电器动作特性分析

针对特高压交流输电线路分布电容大、故障后渡过程明显的特点,从分布参数线路模型入手,分析了正常运行和接地故障状态下,接地阻抗继电器测量阻抗的变化规律,证实了故障情况下测量阻抗与故障距离呈双曲函数关系,提出了一种新型接地阻抗继电器电流接线方式,并探讨了P值常数化、线性化的相关问题.理论分析和测试结果表明:对于400 km以下的特高压交流输电短线路,接地阻抗继电器可以基于集中参数模型整定;但是对于400 km以上的长线路,在基于分布参数模型整定阻抗继电器和采用新型电流接线方式的基础上,方向性接地阻抗继电器能够正确判别故障发生、检测故障位置.     

交流1 000 kV特高压输电线路距离保护特殊问题

与常规电压等级线路和超高压线路相比,特高压线路输电距离较长,线路分布参数特性明显,常规距离保护的理论前提有可能受到影响.文中详细分析了不带并联电抗器和带有并联电抗器2种情形下距离继电器的测量阻抗与线路长度的关系.理论分析和仿真结果表明,可以基本认为在带并联电抗补偿的特高压线路上,常规距离保护的理论前提依然是成立的.     

Residual Compensation for Ground Impedance Relay With Applications in UHV Transmission Lines

The impedance algorithm in distance protection for high voltage (HV) and extra high voltage (EHV) lines, although neglecting the influence of shunt capacitance, is able to produce satisfactory performance. However, the accuracy of the algorithm is significantly reduced when applying to ultra high voltage (UHV) lines due to the larger P.U. line shunt capacitance and longer transmission radius. Therefore, the distributed parameter model should be adopted, and the relay should be set based on the hyperbola function between measuring impedance and the fault distance. However, how to define and set the indexes in relay ever defined with lumped parameters, such as the residual compensation coefficient, is still unresolved. In response to this question, the paper models the UHV system with distributed parameters and introduces the concept of virtual equivalent line length controlled by zero sequence system impedance, and then proposes a novel residual compensation coefficient. Case studies and RTDS tests show that the relay with proposed coefficient offers good performance for the simulated cases. The results also can be extended into other applications, such as the design of zero sequence reactance relay, fault location, fault phase selection, power swing blocking, and load blocking components.      

特高压交流1000 kV示范工程故障电流谐波分析

根据国家电网公司提供的交流特高压示范工程二次系统研究用关键参数与边界条件,采用输电线路分布参数法,理论计算晋东南—南阳—荆门交流示范工程充电合闸、不同位置故障的电流谐波分布,了解特高压1000kV交流输电短路的过渡过程可能出现的现象及对继电保护的影响,对1 000 kV交流示范工程的继电保护研究具有一定的指导意义。     

RTDS Environment Development of Ultra-High-Voltage Power System and Relay Protection Test

The increased interest in using ultra-high-voltage (UHV) transmissions has stimulated the research on UHV operation characteristic and correlative relay protections. Since the operational experience in UHV system is limited, there is a need to model UHV transmission systems and test the performance of traditional protection devices already in use on high-voltage and extra-high-voltage systems. This paper presents the development of a test environment based on a real-time digital simulator of a UHV power system model and the results of testing a distance relay using the model. It reveals that the protective zone is enlarged in the UHV system with shunt reactor compensation and is reduced without the compensation. To resolve these issues further investigation is needed and ways of resolving them, including the development of new algorithms, should be examined.     

用于特高压输电线保护的能量方向元件

传统能量方向元件在特高压线路中不能正确判别故障方向,同时当线路出口发生故障时由于系统内阻很小而导致有功能量方向元件也不能做出正确的判断。提出了一种应用于特高压长距离输电线路的故障分量式能量方向元件,并且提出了相应的方向纵联保护原理,用贝瑞隆算法加以实现;从而使保护的可靠性大大提高;分析了保护判据及其动作特性。通过数字仿真证明了所提方向元件原理和保护判据的正确性和可靠性,该元件具有不受系统暂态过程、过渡电阻、串补电容等因素影响的特性,而且其灵敏度不受故障类型及故障位置等因素的影响,同时动作速度也较快,不大于20ms。     

1000 kV交流输电系统动态模拟研究

为了准确模拟1000 kV交流输电系统,基于晋东南- 南阳-荆门交流特高压试验示范工程提供的参数,设计了满足要求的高性能线路元件模型(线路阻抗角可高达88．5°)、并联电抗器元件模型、电容式电压互感器及电流互感器等。建立1000 kV交流输电系统的动态模拟系统能够为所模拟系统继电保护装置的设计和选型提供试验条件,并可应用于1000 kV交流输电系统暂态特性的研究。     

基于改进暂态能量方向的半波长输电线路保护方法

针对传统特高压保护方法难以直接应用于特高压半波长交流输电系统的问题,提出基于改进暂态能量方向的半波长输电线路保护方法.半波长输电线路测量阻抗随故障位置不再呈现单一线性变化,导致传统距离保护不能直接应用于半波长输电线路,而行波在超长线路上衰减损耗极大,难以准确检测行波波头,故行波保护亦难以用于半波长输电线路保护.因此,提...     

特高压输电线路保护配置设计及应用

特高压输电线路具有电压高、线路长、输送功率大、波阻抗小、分布电容大、线路充电电容电流大等特点,使得电气特征发生了大幅度变化,给特高压系统继电保护带来相当大的影响。本文探讨了特高压输电线路继电保护面临的问题,论述了适用于特高压输电线路的继电保护技术,提出了继电保护配置设计的原则,并在实际工程中提出配置设计的具体应用方案。     

1000kV特高压输电线路保护的现状及发展

1000kV特高压输电系统由于其分布电容引起的故障暂态分量与500kV系统有本质的区别,因此研究1000kV特高压输电线路保护首先必须要研究1000kV特高压系统的暂态特性以及与500kV线路保护的区别。文章介绍了目前关于1000kV特高压输电线路保护研制过程中所关注的一些主要问题,如1000kV特高压系统暂态过程,特高压保护的关键技术问题等,对1000kV特高压输电线路保护提出了基于分布式模型的电流差动保护和距离保护测量原理。经过大量的动模试验验证：目前1000kV特高压输电线路保护完全能满足特高压电网安全稳定运行的要求。     

基于测后模拟原理的半波长输电线路暂态量纵联保护

针对特高压半波长超长的输电距离带来的继电保护难题,提出基于测后模拟原理的半波长输电线路暂态量纵联保护方法.特高压半波长交流输电具有传输距离远、输送容量大、全线无功自平衡等优点,可以作为未来清洁能源电力输送的一种可选方案.通过分析现有输电线路保护方法对于半波长交流输电线路的不适用性,对特高压半波长输电线路在区内外故障情况...     

新型超高压输电线路保护方案的研究

介绍了一种基于DSP的新型超高压输电线路微机保护方案。它采用双主双后的配置 ,重合闸相对独立。在保护原理方面采用了补偿电压突变量方向元件和双原理综合接地距离继电器等新方案 ,并在软件流程方面采取了模块化设计 ,从而大大提高了保护性能。该方案结构紧凑 ,可靠性高 ,人机界面友好 ,通讯功能强大 ,适用于各种超高压输电线路保护     

特高压交流输电线路与航空中波导航台间防护距离计算

与500kV输电线路相比,1000kV特高压输电线路具有电压高、杆塔高、线路走廊宽等特点,对航空中波导航台的无线电干扰更复杂。GB6364-1986《航空无线电导航台站电磁环境要求》未对1000kV特高压输电线路与中波导航台间的防护距离作出规定,给特高压线路选址造成不确定因素。为此,分析了特高压交流输电线路对航空中波导航台的有源干扰和二次辐射产生机理,根据中波导航台的工作方式,结合中波导航台引导飞机进场着陆路轨迹,计算特高压输电线路对航空中波导航台的航线,以及远、近距导航台的有源干扰,仿真分析特高压交流输电线路二次辐射对无线电罗盘的定向误差影响。计算结果表明,从有源干扰角度考虑,取15dB的防护率,对于航线导航台,在距离天线中心38.9km内均可架设特高压输电线路;对于远近距导航台间任意点均可架设特高压输电线路;从无源干扰角度考虑,无线电罗盘定向误差≤1°,则防护距离为700m。选取两者中较大者作为防护距离的计算值,最终的防护距离还需结合试验确定。     

Distance-differential protection of transmission lines connected to wind farms

Distance relays are often used in the protection of the transmission lines connected to the wind farms. The distance relay using the transmission line impedance measurement identifies the type and location of the fault. However any other factors that cause the failure of the measured impedance, makes the relay detect the fault in incorrect location or do not detect the fault at all. One of these factors is the fault resistance which directly increases the measured impedance by the relay. One of the methods to eliminate relay under-reach effect is using of the trip boundaries. Trip boundaries are changing with wind variation and following with output power of the wind farms. Therefore, trip boundaries should continuously change proportional by the wind speed. In this paper, a method is provided based on the combination of distance and differential protection. In this method, using active power calculation in both ends of the transmission line, fault resistance is calculated and its effects are directly deducted from the calculated impedance by the relay. Therefore, variable trip boundaries are not needed anymore. Also in this method, unlike the technique that the trip boundaries are used, the exact location of fault and its distance from the relay also is calculated. Detailed model of a doubly-fed induction generator (DFIG) driven by a wind turbine is used in the modelling. Results of studies show that the presented method eliminates properly the mal-operation of relays under all different fault resistance conditions.     

基于自适应阻抗继电器的风电T接线路纵联保护方案

风电的T型接入改变了系统拓扑和故障特性,导致继电保护整定与配合困难,传统距离保护应用于风电T接线路时存在适应问题。基于风电T接线路拓扑,分析了双保护方向对保护范围的影响,推导了测量阻抗表达式并提取了主要影响参数,指出风电的T型接入影响距离保护的动作性能;鉴于此,提出了基于自适应阻抗继电器的风电T接线路纵联保护方案。该方案实现了保护方向的唯一化,且保护动作区域能够根据过渡电阻、三端电源电势幅值比、相位差和风电电源等效序阻抗的变化进行自适应调整,提高了保护的可靠性和灵敏性。同时给出了自适应整定阻抗的具体计算方法,一定程度上降低了保护对通信系统的要求。仿真结果验证了所提保护方案的正确性和有效性。     

高压输电线路距离保护克服过渡电阻能力研究

高压输电线路中存在较大的过渡电阻,很容易引起距离保护拒动或误动.分析特高压单侧电源经长线路出口故障和双侧电源长线路出口故障时过渡电阻对距离保护工作的影响,探讨单侧电源助增电流网络、外汲电流网络中过渡电阻对测量阻抗的影响,并给出2种网络结构在不同地点处保护测量阻抗的计算公式.研究能较好躲过渡电阻特性的零序电抗继电器、自适应接地距离继电器、神经网络距离继电器,分析比较不同方法的优缺点及适用场合.