摘要:电力系统继电保护技术有四个重要基本要求,分别为快速性,灵敏性,选择性以及可靠性。行波保护易受各种高频信号的影响,因此保护的可靠性会有所降低。基于故障分量的基波正序突变量方向保护原理已成功应用于电力系统,但传统方法采用全波傅里叶算法来计算基波正序突变量相量,保护动作时间在一个基波周期以上。本文基于帕克变换原理,提出一种快速计算基波正序突变量相量的新方法。该算法极大提高了保护动作速度。经过理论分析及做了大量的仿真试验,最终显示所提算法能够快速、可靠地判断各类故障方向,其性能不受故障电阻、系统参数等的影响,具有良好的工程应用前景。62001
毕业论文关键词: 可靠性;帕克变换;高速;方向保护;故障分量网络
Abstract:Power system protection should meet four basic requirements, namely selectivity, speed and mobility (fast), sensitivity and reliability. The conventional travelling wave protection is susceptible to the high frequency transient quantities, which can reduce the protection reliability. A directional-relay algorithm based on positive sequence superimposed components is proposed in this study. In microprocessor relays, the extraction of fundamental frequency voltages and currents is, conventionally, provided by phasor estimation methods such as the Fourier algorithm. The common required time for fault detection in these relays is approximately one to two cycles. This study presents a high-speed algorithm for the extraction of fundamental frequency positive sequence voltages and currents superimposed components based on Park transformation. In the meantime, specially designed high speed algorithms to solve the difficult problems that exist in a real system are proposed. Extensive simulations are performed to evaluate the performance of the proposed algorithm. The results show that the algorithm is fast and reliable for power transmission line protections. Also it is immune to fault resistances and system condition.
KEY WORDS:reliability;park transformation;high speed;directional protection; fault component network
1.绪论 1
1.1研究背景和意义1
1.3主要研究内容2
2.基于叠加原理的电力系统故障分析及正序故障附加网络 2
2.1概述2
2.2基于叠加原理的电力系统故障分析5
2.3基于叠加原理的电力系统故障分析7
3.故障分量方向保护原理研究9
3.1概述9
3.2工频变化量方向元件11
3.3正序故障分量方向元件12
3.3.1故障分量的提起13
3.3.2反应正序故障分量的方向元件13
4.正序突变量相角高速方向保护元件 15
4.1高速方向元件算法15
4.1.1改进的故障分量提起方法15
4.1.2滤除衰减直流分量17
4.1.3差分滤波后电流故障分量的补偿17
4.1.4正序故障分量快速算法18
4.1.5方向判据22
4.2仿真测试23
4.2.1典型故障仿真23
5.结论 26
致谢 29
参考文献 30
1.绪论
1.1 研究背景和意义
随着我国超高压及特高压输电线路的不断建设,电网的互联对电力系统继电保护提出了更高的要求,在保证安全性的前提下寻求对系统故障的快速切除方法是继电保护技术为保障电力系统稳定提供的最有效的措施之一[1]。这极大激发了广大继电保护工作者对高速保护新方法的研究热情,在这方面,方向比较保护扮演了重要的角色[2]。正序故障分量的快速检测算法运用了方向比较保护,对电力系统保护仍然有着重要的意义。
1.2 国内外研究现状
1.3 主要研究内容