输电线路故障测距实用算法研究

针对输电线路双端故障测距算法需要进行双曲函数复杂的计算、牛顿-拉夫逊迭代和二分搜索计算量大、需要精确线路参数等问题,提出了一种新的适合于输电线路差动保护装置的精确故障测距算法。算法原理简单,经过简单的复数运算就可以计算出输电线路的精确参数、两侧非同步采样系数和故障距离。采用正序故障分量来计算故障距离,能适应各种故障类型,计算结果收敛快,不受过渡电阻影响。     

一种基于行波测距的输电线路接地故障距离保护方案

对于行波测距式距离保护 ,区分正向与反向故障在理论上已经有较完善的方法 ,但区分正方向区内、区外故障的方法理论上还不完善 ,需要进一步的研究。本文在对现有行波测距方法分析的基础上 ,提出了一种零模测距方法和线模测距方法相结合的输电线路接地故障距离保护方案。考虑到零模波速受频率和线路走廊地理环境影响比较严重 ,本文还分析了接地保护对零模波速误差的要求 ,分析表明保护对零模波速要求比较宽松。大量电磁暂态仿真证明了本保护原理的正确性     

双端不同步采样的高压输电线路故障测距算法研究

研究双电源的换位、不换位单回以及耦合双回线短路点定位的新方法，其特点为：①两侧之间工频量不必同步。②适于换位和不换位的长线。③线路分布电容、过渡阻抗和系统运行方式等因素对测距精度没有影响。大量的模拟故障测距数字仿真表明，本方法具有较高测距精度。     

多端线路电流差动保护实现故障定位及测距的新方法

多端线路具有多个T节点及分支的复杂性,已有的故障定位和测距方法不能直接应用到保护装置中。为此,提出通过故障类型选择故障定位和测距的序分量,以提高测距精度,即相间故障和三相故障时采用正序分量,而单相接地故障,多端线路所有节点的正序电压差小于预设阈值时采用零序分量,否则采用正序分量。为解决多端线路测距计算量大的问题,结合二分搜索法,通过评估T节点不同侧序分量电压的差异,实现多端线路的故障定位;将故障点两侧的电气量节点等效为双端系统,按选择的序分量进行双端故障测距。该方法经RTDS入网试验,可以满足现场要求,对比固定采用正序分量的测距方法,在高阻接地故障时具有明显的优势。     

架空线路短路故障点测距装置研制

介绍了1种新的架空线路故障测距方法。该方法只测量线路的电流,测量精度不受短路过程电阻的影响。根据该方法研制成以80C196单片机系统为主的架空线故障测距装置。经电力系统模拟试验：该装置对点能准确定位,测量误差在3%以内,具有较高的工程实用价值。     

新型输电线路单端电气量组合故障测距方法及其试验研究

针对原有的组合测距方法中阻抗法测距精度较低、划定故障范围较大而导致可能出现精确行波测距失败的问题,提出采用基于分布参数模型的阻抗法配合行波法构成新型单端组合测距算法,进而在高精度故障录波与测距系统硬件平台上实现了所提出的方法,并用RTDS和暂态行波保护测试仪对该方法进行了系统的测试检验。测试结果表明,所提故障测距方法在测距精度、测距稳定性和鲁棒性等方面都有了提高。最后分析了所提方法产生误差的原因。     

不受TA饱和影响的高压输电线路故障测距算法

基于线路分布参数模型,考虑电流互感器（TA）饱和或断线导致某一侧电流畸变或不可用的情况,提出了一种输电线路故障测距新算法。该方法通过分析短路序网关系,利用两侧电压和未饱和侧电流,求出不同短路类型下沿线电压和电流的分布,根据过渡阻抗的纯电阻性质,得出当且仅当在故障点处电压和流经过渡电阻的电流的相位相同,由此定位故障点。因此,该测距方法可以不受一侧TA饱和或断线的影响。ATP-EMTP仿真结果也证明了该方法正确、有效。     

一种使用两端电气量的高压输电线路故障测距的新算法

本文提出了一种使用高压输电线路两端电气量进行故障测距的新算法。     

高压输电线路故障测距算法仿真研究

本文对目前常用的高压架空输电线路测距算法进行了大量的仿真计算，总结这些算法的特点和存在的主要问题，并在此基础上提出了更完善的解决方案。     

具有自主知识产权的新型输电线路故障距离测距装置研制成功

输电线路故障后快速寻找故障点是保证电网安全稳定运行的一项关键技术，也是长期以来困扰电网运行的世界性技术难题之一。近日国内成功开发和研制出具有国际领先水平的且具有我国自主知识产权的输电线路故障测距装置(测距误差小于500m)。     

A new distance relaying algorithm based on complex differential equation for symmetrical components

This paper presents a new digital impedance measuring technique for transmission lines that combines symmetrical components and the complex differential equation of an equivalent fault loop circuit. The phase voltages and currents at the relaying point are transformed into symmetrical components using Fourier filters of short window length. Depending on fault type, an appropriate fault loop circuit is formed, signals of which are the appropriate symmetrical components, while a parameter of which is the positive sequence impedance being a geometrical measure of the distance from the relaying point to a fault. The impedance, however, is measured very fast by on-line solving the complex differential equation originated for this fault loop circuit. Consequently, this approach combines frequency domain estimation of symmetrical components (accurate filtration) and time domain measurement of positive sequence impedance (high speed response).

The presented method suits well the protection of parallel lines against high-resistance faults occurring very close to the far end of a line. A new method is proposed for detecting high-resistance faults and deciding which line out of two parallel lines actually suffers a fault.

The included EMTP test results demonstrate the efficiency of the proposed relaying algorithm.     

A new algorithm for finding the optimal solution of the least absolute value estimation problem

In this paper an algorithm is developed which uses contraction mapping to determine the optimal solution of the least absolute value (LAV) static estimation problem. It is noted that the new algorithm is computationally simpler than other methods currently available for this purpose. Minimal computational effort is required to obtain the LAV estimates.     

A recursive least-squares digital distance relaying algorithm

A new digital distance relaying algorithm based on the well-known theory of least-squares is developed, and the results of testing it using numerical simulation are presented. The new technique estimates the distance to the fault and the fault resistance. To minimize the computational requirements of the digital relay, a recursive least-squares approach is used. Computer simulation results of the new least-squares algorithm seem promising, indicating that it should be considered for further testing and evaluation     

A switching-parameter algorithm for finding multiple solutions of nonlinear resistive circuits

An efficient algorithm for finding multiple solutions of a system of nonlinear algebraic equations is presented. This algorithm consists of solving an associated system of first order nonlinear differential equations whose independent variable may be switched from one variable to another during each integration step. The choice of the forward Euler predictor and Newton-Raphson corrector for integrating the differential equations leads to an extremely efficient method for implementing this switching-parameter algorithm. This approach involves only the recursive solution of an associated system of linear algebraic equations and can be easily programmed. The switching-parameter algorithm can also be used to derive the driving-point or transfer characteristic curve of multivalued resistive nonlinear networks.     

A simplified algorithm for digital distance protection based onFourier techniques

Algorithms for digital distance protection based on Fourier series techniques are examined. An approach based on a variable-frequency sampling technique is proposed. The algorithm is examined from a theoretical point of view, and its behavior is simulated under fault conditions typical of the Italian electrical network. The algorithm is shown to behave in the same way as other Fourier series-based algorithms and to have the advantage of reducing the computational burden     

Variable-window algorithm for ultra-high-speed distance protection

This paper presents a new concept in ultra-high speed distance relay for power line protection. The idea is based on the use of a sampling window shorter than usual to speed commutation. The reduction in protection time is obtained through a variable window that is expanded sample by sample until a satisfactory precision is reached in the calculation of fault quantities. The right window length is obtained automatically via software and time-by-time changes depending on the characteristics of the fault. The algorithm is based on the equation associated to the R-L fault circuit, whose solution is obtained using the phase modified Fourier transform. To validate the proposed procedure, a large number of simulations are performed with reference to an existing 150-kV subtransmission line. In comparison with other solutions, the relay proposed here is very cost-effective and makes it possible to achieve ultra-high speed fault localization not only on high-voltage (HV) networks but also on medium-voltage (MV) distribution networks.     

A new superfast bit reversal algorithm

In this paper we present a new bit reversal algorithm which outperforms the existing ones. The bit reversal technique is involved in the fast Fourier transform technique (FFT), which is widely used in computer‐based numerical techniques for solving numerous problems. The new approach for computing the bit reversal is based upon a pseudo‐semi‐group homomorphism property. The surprise is that this property is almost trivial to prove but at the same time it also leads to a very efficient algorithm which we believe to be the best with only ?? (N) operations and optimal constant, i.e. unity. Copyright © 2002 John Wiley & Sons, Ltd.     

一种新型SOC估计算法的研究

在建立电池管理系统的过程中,动力电池荷电状态(SOC)的实时测量和估计很关键。分析了各种电池SOC估算方法的优缺点,提出了一种实时检测电池端电压作为判断电池充电状态的电压-安时计量算法。由该算法构成的电量计能实时、准确计算电池的电量和SOC,保证了动力电池在电动汽车应用中的安全、可靠运行。