【作者】 张华中；

【导师】 王维庆；

【作者基本信息】 新疆大学 ， 电力系统及其自动化， 2009， 硕士

【摘要】 本文首先论述了距离保护的基本原理和动作特性,基于输电线路单相接地故障分析过渡电阻对单侧电源和双侧电源系统距离保护测量阻抗的影响。介绍了自适应距离保护的基本概念,并根据电力系统现阶段的发展趋势,针对不同的系统提出了两种自适应距离保护。在倡导绿色能源的今天,风力发电是目前最成熟、经济效益最好的一种可再生能源发电技术,我国风资源较丰富,但适合大规模开发风电的地区一般都处于电网末端,高压输电线路将成为输送偏远电能的有效载体。风力发电自身的特殊性导致了输电线路距离保护的难以整定。本文分析了风电场和电网联络线的距离保护随电源电势幅值比、电势相位差、电源等效阻抗、系统频率等参数变化时的动作特性,基于风电场侧的实时电流和电势与参与发电的发电机信息提出了仅利用风电场侧信息量距离保护的自适应整定方法。自适应动作特性边界是非线性的,本文利用两种不同的原理实现这种动作特性。仿真结果证明了这种自适应整定方法具有优良的性能。我国经济快速增长和500kv输电线路的建设发展,线路走廊的选择越来越困难和拆迁费用日趋增长,尽可能的压缩输电线路走廊和增加输送容量成为输电线路发展的主题,因而同塔多回输电技术越来越得到我国电力行业领导和专家的重视。平行双回线结构的特殊性以及零序互感等因素造成继电器耐受过渡电阻的能力较弱,严重影响继电器的性能,传统的距离保护难以满足高压平行双回线的要求,本文基于双回输电线路的一回线路各种接地故障,根据它们的故障边界条件计算出流经故障点处正、负、零序电流的权重系数,并借助正、负、零序电流的权重系数和传统距离保护的测量阻抗计算出保护的附加测量阻抗,修正传统距离保护的测量阻抗,提出双回输电线路的自适应距离保护,同时给出正、负序电流分支系数相角的估算方法。仿真结果证明了这种自适应方法具有优良的性能,能有效防止保护的超越和拒动。故障测距也为输电线路距离保护的一部分,本文基于故障时沿线电压的分布规律提出了两种实用性较强的故障测距算法,利用线路两侧的电压和电流正弦相量计算故障距离,不要求双端数据的同步,能消除过渡电阻的影响,具有较高的工程实用价值。文中着重对输电线路故障测距方法进行可行性验证,采用ATP仿真获得故障线路的电气量值,并用Matlab计算故障点位置,仿真结果表明本文所提出的方法有较高的精度,能满足现场实际要求。更多还原

【Abstract】 Firstly the basic principles and operation characteristics of distance protection are discussed in this paper.According to single-phase-to-ground fault of the tranmission lines,influences of transition resistance on impendance measurement of both unilateral power system and bilateral power systems are studied. Fundamental concepts of adaptive distance protection are presented. Based on present delopment direction of power system two kinds of methods of adaptive distance protecion are shown aiming at different system.Green energy is advocated in these days. Wind power generation is a kind of the most mature and the best economic renewable energy power generation technolgy. In our country wind resoures is rich,but generally regions suitable for large-scale development of wind power are at the end of the grid.Thereof high voltage transmission lines become the effective carrier of romote power. It is difficult to set the transmission line protection of wind farm due to its own particularity. The authors analyze the operation characteristic of distance protection of transmission line connecting wind farm with power grid under the variation of parameters such as the amplitude ratio of electromotive force at both sides, the phase difference of electromotive force at both sides, equivalent impedance of sources, system frequency and so on.Based on the real-time current and electromotive force at wind farm side as well as the information of wind power generators participating power generation, a method to adaptively set the operation boundary of distance protection by use of the information at wind farm side only is proposed. The boundary of adaptive operation characteristics is nonlinear, and it is realized by two differernt principles in this paper. Results of simulation show excellent performance of the adaptive setting method.In our country,with the development of rapid economy and 500kv tranmission line construction line corridor selection becomes more and more difficult and the cost of demolition is increasing. It becomes the developing theme of transmission line that transmission line corridors is compressed to and transmission capacity is increaseing as much as possible , Thereby multi-circuit transmission line technology on the same tower is paid attention to by leaders and experts from the power industry. Weaker ability of enduring transition resistance is caused by particularity of parallel double circuit line configuration and zero sequence mutual induction etc, which seriously affects performance of relay. Therefore it is difficult for traditional distance relay to satisfy high-voltage parallel double circuit lines. Based on various faults of single line of parallel double circuit transmission line, on the basis of their boundary conditions weighting coefficients of positive- negative- and zero-sequence currents are calculated. The paper is in virtue of weighting coefficients of positive- negative- and zero-sequence currents and measured impedance of traditional distance protection to calculate additional impedance which is used to revise measured impedance of traditional distance protection, and advances adaptive distance protection of double-circuit transmission lines. Moreover the method estimating phase angles of embranchment coefficients of positive- and negative-sequence current is presented. Results show that the adaptive method has excellent performance and effectively avoids transient overreaching and under-reach of distance protection.Fault location is a part of transmission line distance relay. Two practical algorithms are presented based on the distributed regularity of voltage along the transmission line when fault occurs in the paper. Fault location is calculated using current and voltage sinusoidal phasors at both ends without necessity of data synchronization, and the influence of fault resistance can be eliminated. So they have more practical values. The verification of their feasibility is emphasized in the paper. The electric parameters are acquired by ATP simulation and the fault location is calculated with Matlab programming. Lots of simulation results show these methods presented in the paper can precisely locate the fault site and completely satisfy the practical need in the field.更多还原