Computer-aided protective relay setting system for large power networks

This paper introduces a protective relay setting system capable of handling a large network up to 10,000 buses. The remarkable features are such useful functions as network analysis (fault analysis, load flow calculation, zero-sequence current calculation, etc.), relay operation simulation, and automated setting coordination tasks. Fault currents in the maximum and the minimum operation networks are calculated to examine the setting values. The protection zones are searched automatically along the network connection. Protection coordination tasks among the primary and the backup relays composed of different types of relays can be performed by the relay operation simulation. The system is built on an engineering workstation, which works in cooperation with other network operation support systems. Its graphical user interface helps every engineer to examine the relay setting using a variety of databases.     

可视化地铁供配电系统继电保护整定软件的开发

在分析地铁供配电系统继电保护整定的特殊性的基础上,开发了一套适用于地铁供配电系统的继电保护整定软件。软件以实用性、可扩展性和界面友好性为设计原则,基于典型的三层架构进行开发,参考IEC61970标准提出的公用信息模型（CIM）并结合地铁供配电系统实际对元件进行建模,采用图模一体化技术提供友好整定界面,可结合用户经验进行保护定值的整定,提高了整定结果的可靠性。介绍了软件的应用情况,并对软件的进一步完善进行了探讨。     

Wavelet transform based digital protection for transmission lines

This paper presents a high speed, computationally efficient scheme for protection of transmission lines. The relay logic consists of three parts: directional protection, fault classification and fault location. Wavelet transform is used for extracting information from the fault transients and only the first level high frequency details of the voltages and currents are used. Proposed protection logic compares the directional signals from both terminals to discriminate between faults inside and outside the zone of interest. Fault classification is achieved using local terminal current information. An estimate of the location of the faults is obtained utilizing single faulted phase current information from both terminals. The logic is deterministic and can work reliably in the presence of fault resistance, load variation and CT saturation. The validity of the proposed logic was exhaustively tested by simulating various types of faults on a four bus meshed system modeled in EMTP/ATP.     

220 kV线路保护整定计算的简化实践

随着电网单端电源供电220kV终端变电站越益增多,相应的继电保护整定和计算也越显重要。介绍了江苏电网220kV线路继电保护整定计算的主要特点,就实际运行中三种运行方式的优缺点进行了分析和比较,最后叙述了地区电网110kV系统中带小电源的220kV线路继电保护的整定计算方案,运行实践表明,经过简化后的整定计算方案,符合江苏电网实际运行的要求,取得了较好的效果。     

光纤迂回通道可靠传输继电保护业务的应用研究

现行的继电保护信号传输方案给SDH等通信设备的运行维护、网管操作带来很大压力，针对继电保护信号高可靠性传输的要求，文章提出了光纤迂回通道和继电保护业务自动倒换的传输方案，论证了光纤迂回通道传输的可行性，并运用故障树法对几种自动倒换方案进行可靠性分析和比较，得到结果证实PCM自动倒换光纤迂回传输方案，能较大地提高继电保护业务的传输可靠性。     

基于神经网络的110kV双电源线路阻抗继电器

提出一种基于神经网络的 110kV双电源线路单相接地阻抗继电器新原理。通过电磁暂态仿真程序(EMTP)对给定电力网络进行大量的仿真计算 ,证明了该阻抗继电器不仅能适应系统工况和过渡电阻的变化准确地进行故障定位 ,还具有故障选相和故障测距的功能。     

Wavelet entropy based algorithm for fault detection and classification in FACTS compensated transmission line

Distance protection of transmission lines including advanced flexible AC transmission system (FACTS) devices has been a very challenging task. FACTS devices of interest in this paper are static synchronous series compensators (SSSC) and unified power flow controller (UPFC). In this paper, a new algorithm is proposed to detect and classify the fault and identify the fault position in a transmission line with respect to a FACTS device placed in the midpoint of the transmission line. Discrete wavelet transformation and wavelet entropy calculations are used to analyze during fault current and voltage signals of the compensated transmission line. The proposed algorithm is very simple and accurate in fault detection and classification. A variety of fault cases and simulation results are introduced to show the effectiveness of such algorithm.     

220 kV线路保护装置整定计算应注意的问题

整定计算是继电保护工作中的重要部分,为此,对线路保护装置定值进行了分析和总结,阐述了广东电网220kV线路保护装置整定定值的取值原则,并提出了需要注意的问题。     

Phasor measurement unit based transmission line protection scheme design

This paper presents an adaptive transmission line protection scheme based on synchronized phasor measurement units. This scheme uses the positive-sequence voltage and current phasors at both ends of a transmission line to determine the parameter of the transmission line and the location of a fault on the transmission line. This scheme can be used for the protection of both single- and double-circuit transmission lines. This scheme is also robust against power swing conditions. A novel adaptive single pole auto re-closer is introduced based on the proposed scheme due to its capability of differentiating transient and permanent faults. System simulation studies show that the proposed scheme is able to operate fast and accurately for transmission line protection.     

风电接入对继电保护的影响(六)——风电场送出线路距离保护影响分析

从感应发电机基本原理出发,在转子转速旋转磁场坐标下,建立感应发电机简化三阶动态模型。从电路角度分析了风电场送出线电压、电流主频不同的机理,因此依据工频傅氏算法的相量距离保护元件的动作性能受到严重影响。利用Prony等算法分别提取保护安装处电压、电流工频及转速频率分量,可以准确测量出故障线路阻抗;基于线路时域微分方程模型的解微分方程算法距离元件不受信号频率影响。PSCAD/EMTDC仿真结果验证了分析的正确性。     

750kV示范工程官亭-兰州东线路保护整定探讨

目前,国内首个750 kV输变电示范工程已正式投入运行。在国内尚无明确规程的情况下,结合现有的继电保护相关规程,探讨了750 kV示范工程线路保护配置和整定原则。针对750 kV超高压系统的有关特点,提出750 kV线路保护必须满足双重化要求,主保护应采用不同原理。同时,结合750 kV输变电示范工程实际,分析探讨了差动保护有关定值的整定,并对750 kV线路距离和零序后备保护的灵敏度要求作了论述。最后,对零序电流保护最末段的抗过渡电阻能力的深入分析表明,该段设置为300 A时能够适应400Ω过渡电阻。     

基于J2EE和Matlab的发电厂继电保护综合管理系统

基于J2EE平台和Web服务的综合集成方案,既能充分利用J2EE平台的成功优势,又能以互操作性更好的方式展现整合企业信息系统功能。面向服务层,将计算平台、图形化平台集成于统一的信息化管理平台之中。介绍了一种面向服务层的基于J2EE和Matlab的发电厂继电保护综合管理系统。分析其总体结构、主要功能模块和技术特点。系统采用分布式J2EE架构,与Matlab有机结合,实现了发电厂继电保护信息管理、故障分析、保护整定等功能。该系统具有较好的实用性和通用性。     

A transient current based double line transmission system protection using fuzzy-wavelet approach in the presence of UPFC

This paper presents a wavelet fuzzy based protection scheme for a double line transmission system with unified power flow controller. The protection scheme makes use of current signals at both the ends of transmission line which are synchronized with the help of global position system clock. A wavelet based multiresolution analysis is used to find the detailed coefficients of these signals which are utilized to calculate fault index. These fault indexes are compared with a threshold value to detect and classify faults on transmission system. The approximate decomposition of the current signals is utilized to locate the fault using Fuzzy logic from their respective terminals. The proposed algorithm has been tested successfully for various faults at different locations.     

贵阳电网110kV线路优化保护配置及整定计算的探讨

对贵阳地区电网运行现状的分析,针对其110kV线路保护的配置情况和整定计算,提出了优化方案。方案中,通过对110kV线路配置光纤电流差动保护,强化主保护,简化后备保护的整定原则,能够进一步提高110kV线路保护可靠性,有效地减轻维护工作难度,提高继电保护整定计算的工作效率,对运行方式的安排也提高了灵活性。     

Accurate phasor measurement for transmission line protection in the presence of shunt capacitor banks

This paper proposes a phasor measurement algorithm for transmission systems compensated with shunt capacitor banks. Since the shunt capacitor banks tend to lower the resonant frequencies, the dominant component, which has the lowest resonant frequency, is insufficiently attenuated by a low-pass filter and has an adverse influence on the phasor measurement of the fundamental component in a fault current signal. This paper theoretically investigates the dominant frequency in the presence of shunt capacitor banks and presents a phasor measurement algorithm immune to the dominant component and DC-offset. The performance of the algorithm is evaluated for a-phase to ground (a–g) faults on a 154-kV transmission system compensated with shunt capacitor banks. The evaluation results indicate that the algorithm can measure the phasor reliably and satisfactorily, although the fault current signal is distorted with the dominant component and DC-offset. The paper concludes by describing the hardware implementation of the algorithm on a prototype unit based on a digital signal processor.     

Proposal of an alternative transmission line model for symmetrical and asymmetrical configurations

This article shows a transmission line model for simulation of fast and slow transients, applied to symmetrical or asymmetrical configurations. A transmission line model is developed based on lumped elements representation and state-space techniques. The proposed methodology represents a practical procedure to model three-phase transmission lines directly in time domain, without the explicit or implicit use of inverse transforms. In three-phase representation, analysis modal techniques are applied to decouple the phases in their respective propagation modes, using a correction procedure to set a real and constant matrix for untransposed lines with or without vertical symmetry plane. The proposed methodology takes into account the frequency-dependent parameters of the line and in order to include this effect in the state matrices, a fitting procedure is applied. To verify the accuracy of the proposed state-space model in frequency domain, a simple methodology is described based on line distributed parameters and transfer function associated with input/output signals of the lumped parameters representation. In addition, this article proposes the use of a fast and robust integration procedure to solve the state equations, enabling transient and steady-state simulations. The results obtained by the proposed methodology are compared with several established transmission line models in EMTP, taking into account an asymmetrical three-phase transmission line. The principal contribution of the proposed methodology is to handle a steady fundamental signal mixed with fast and slow transients, including impulsive and oscillatory behavior, by a practical procedure applied directly in time domain for symmetrical or asymmetrical representations.     

Wavelet transforms for real-time estimation of transmission line impedance under transient conditions

 Waveforms of voltages and currents in electrical power systems may include higher harmonics, transient components and random noise. For control and protection devices, it is necessary to estimate parameters of the basic waveform. The most well-known methods are based on the Fourier technique. The estimated phasors of the basic component can be applied to the calculation of the impedance of a faulty transmission line. In this paper, the current and voltage phasors were estimated using complex wavelets. The filter properties of the wavelet approach are better than those of the Fourier. Received: 20 July 2001/Accepted: 10 August 2001     

A new method for the analysis of cross-country multifaults in a double-circuit transmission line

To analyze multifaults on a power line, many complex calculations must be performed. Hence, in many cases, computers are employed in the actual phase domain. However, it is difficult to determine the property and/or the physical meaning of the calculated results because the computer method is based on many complex numerical calculations. This paper represents a new analytical method for short-circuit studies which can deal with cross-country multifaults in a double-circuit transmission line with zero-sequence mutual coupling. This method is based on the well-known “two-component network theory” for a balanced three-phase double-circuit. Procedure steps are: (1) represent the network as seen from the faulted points with symmetrical component impedance; (2) construct the symmetrical equivalent circuits for faults with imaginary phase-shifting transformers; (3) combine these equivalents with each other and erase the symmetrical voltages at faulted points because the phase voltages at such points are known; and (4) calculate the currents at the faulted points by solving the simultaneous linear equations. This method is applied to an investigation of distance-relay “underreach” phenomena where crosscountry multifault occurred on a double-circuit transmission line. Effects of line constants on these phenomena have been well understood.     

基于嵌入式系统的输电线舞动在线监测系统

本文研究了一套基于嵌入式系统的输电线舞动在线监测系统的设计原理与实现,该系统是由USB摄像头,嵌入式计算机系统和GPRS模块构成。在嵌入式计算机系统中实现了嵌入式Linux的裁减,定制和移植,并在此基础上实现了基于Qtopia的应用监测程序的编写。该监测系统是以嵌入式计算机为载体,以USB摄像头采集到的图像数据为基础。实现了基于无线GPRS的电力设备的输电线的远程实时在线监测。     

基于双DSP结构的中低压线路保护测控装置的设计

设计了一种适用于中低压线路的保护测控装置,它采用双DSP结构,充分利用了数字信号处理器的速度快、精度高的优点,保护与测控功能独立实现,既保证保护的可靠性,也保证了测量的高精度。文中介绍了保护测控装置的硬件组成和软件模块的实现。