电力网络结构变更时的三相短路电流计算.doc

电力网络结构变更时的三相短路电流计算
 
内 容 摘 要

在电力系统运行过程中，经常会发生各种故障，最为常见的是各种形式的短路，其中以三相短路最为严重。三相对称短路电流的计算分析是电力系统电气设备选择及设计，继电保护的合理配置及定值整定和运行分析等问题的重要依据。本文基于电力系统短路理论及电力系统故障计算用的数学模型理论，利用节点阻抗矩阵推导出电力网络结构变更时三相短路的实用计算机算法。该算法利用Matlab语言编程完成，大大减轻了传统计算曲线法的工作量，能够自动完成电力网络结构变更时三相对称短路的短路电流、各节点电压及指定各支路电流的求解，并通过实例验证了算法的正确性和合理性，而且具有较高的准确度。

关 键 字
短路电流计算；结构变更；阻抗矩阵； MATLAB
 
Calculation of the three-phase symmetrical short-circuit current in process of the change of the electrical power mesh configuration
02067325 Guorong Tan   Tutor: Yiqin Wang   Lecturerl
                            Dan  Zhang  Assistant
Abstract
In the process of electrical power system, different kinds of breakdowns will frequently crop up, of which the most common ones are various forms of short-circuit, and among them the three-phase short-circuits is the most serious. The computational analysis of the three-phase symmetrical short-circuit current is not only the foundation of the choice and design of equipment in the electrical power system, but also the important basis for those problems of reasonable disposition, definite value of relay protection. Based on the theory of the breakdowns and movement analysis and the mathematical model of the electrical power system, practical computer algorithm for calculating three-phase short-circuits during the change of the electrical power structure is deduced using the node impedance matrix. With Matlab method software, the workload is reduced greatly compared with the traditional computation curve method. This method can automatically complete the calculation of the short-circuit current and the electrical voltage of every node, and the current of nominated branches when the electrical power mesh configuration changes. What’s more, its accuracy and reasonableness have been tested.
Key Words
Calculation of short-circuit current; change of mesh configuration; impedance matrix; MATLAB
 
目   录

1. 绪 论……………………………………………………………1
1.1 论文意义 …………………………………………………1
1.2 研究现状及发展 …………………………………………1
1.3 本论文的主要工作 ………………………………………2
2. 短路的相关概述 ………………………………………………3
2.1 电力系统的短路故障 ……………………………………3
2.2 应用计算曲线计算短路电流 ……………………………5
3. 电力系统网络变更时三相对称短路的实用算法 ……………6
3.1 电力网络的数学模型 ……………………………………6
3.2 三相对称短路的计算 ……………………………………15
3.3 网络结构变更时的三相短路计算………………………19
4. 网络结构变更时三相短路计算机算法的实现 ………………23
4.1所选编程语言介绍 ………………………………………23
4.2程序实现说明 ……………………………………………23
4.3 程序流程图………………………………………………25
4.4 算 例 …………………………………………………26
5. 总 结 …………………………………………………………28
致 谢 ……………………………………………………………28
参考文献  ………………………………………………………29
附 录 ……………………………………………………………30