【作者】 曾超；

【导师】 彭建春；

【作者基本信息】 湖南大学 ， 电力系统及其自动化， 2008， 硕士

【摘要】 高压直流输电具有功率调节快速及运行可靠等优点,在大容量远距离输电的场合和电网互联方面具有极大的优势。因此在我国实施的“西电东送”和全国联网的发展策略中有着极其重要的作用。然而,由于交直流混合系统的复杂性,虽然纯交流系统潮流计算的方法已经非常成孰,但交直流混合系统的潮流计算并没有达到相同水平。为此,本文对交直流混合输电系统的潮流计算问题进行了深入细致的研究。本文首先简要概述了国内外高压直流输电技术的发展情况、交直流混合输电系统的研究现状及急需解决的问题。然后介绍了用于交直流潮流计算的换流器稳态数学模型和交直流混合系统的常用潮流计算方法:统一迭代法和交替迭代法。接下来针对求解非线性方程组的布罗伊登法及其改进方法的原理和步骤进行了详细的分析,指出其主要优点是避免了牛顿法每次迭代都需计算状态函数在当前迭代点的导数或其差商近似值以确定新方向的缺陷,因此计算效率高。继而将改进的布罗伊登方法应用于交直流混合系统潮流计算,给出了相应的计算步骤,设计和编写了相应的潮流计算程序。最后,针对本文提出的基于改进布罗伊登法的交直流潮流计算方法,采用IEEE测试系统进行了仿真计算和分析。计算结果表明本文提出的新方法具有拟牛顿法的特点,计算效率相对较高。本文提出的潮流计算方法不仅程序实现简单、而且对不同结构和运行方式的电网具有广泛的适用性。基于改进布罗伊登法的交直流混合系统潮流计算方法为快速可靠实现交直流系统的潮流计算提供了一种有效途径。它对交直流混合系统运行行为的研究具有重要的理论和实际意义。更多还原

【Abstract】 High Voltage Direct Current (HVDC) technology has advantage in the situation of high-power and long-distance electricity transmission and interlinking of power systems because of its fast power adjustment and reliable operation. HVDC technology will take key role in the implementation of the projects for transmitting power from west to east in the Western China Development Strategy, as well as the project of nationwide interconnection of power grids. At present, the methods of AC system power flow solution have been perfected, but the methods to solve AC/DC systems power flow did not reach the same level because of its complexity. Therefore, this paper makes in depth and meticulous research to power flow solution of AC/DC systems.First of all, this paper outlines the development of HVDC technology, the research of the AC/DC power systems in worldwide and the urgent problems. Then, it introduces a model of the AC-DC converter and the AC/DC systems power flow solution using normal method. The approaches are categorizing into two kinds. The first is the sequential method and the other is named the unified approach. Then, it makes a detailed analysis to the Broyden method and Improved Broyden method which have been used to solve the nonlinear equation effectively in the field of mathematics. They avoid the shortcomings of Newton method that calculates the derivative of the state function in the current iteration point which determines the new direction during each iteration. Consequently, its computational efficiency is more effective. And then, a unified iterative method for AC/DC power flow solution based on the improved Broyden method is proposed and the corresponding power flow program is developed.Finally, a series of tests to the power flow solution using improved Broyden approach are carried out. The results show that the new method has the characteristics of quasi-Newton method and high efficiency. The program based on the improved Broyden method is simple to implement and has strong applicability to different structures and power system operating modes.The new method is an effective approach for solving AC/DC power flow fast and reliably. It has a very important theoretic and practical meaning for the research to the steady operation and the regulation for the AC/DC systems.更多还原