基于分岔理论的电力系统电压稳定分析及控制策略研究

发布时间：2018-11-04 21:33

【摘要】：随着21世纪工业和信息技术的发展以及人民生活水平的不断提高,工业生产设备、家用电器等对电力系统供电质量不断提出更高的要求,如何提供更加安全、稳定、可靠的供电已成为现代电力系统相关技术研究工作的方向。衡量电力系统质量的指标有:电压、频率和谐波。由于世界上已发生的几起电压失稳事故均对当时社会和人民的生产生活造成了严重影响,近年来,电力系统的电压稳定问题备受社会各界和国际电工学会的重视。随着电力工业的不断进步,现代电力系统日益向大电网、大机组、特高压远距离输电的方向发展,各种分布式电源、新能源并网及无功补偿等装置的使用,使电力系统的运行工况日趋复杂,动态因素不断增加,导致电网维持电压稳定的难度不断加大。在该背景下,本文考虑实际工况中的各种不确定因素和动态影响,如动态负荷、无功补偿装置动态特性、发电机动态特性和电磁功率扰动,分别对两种不同的电力系统模型进行改进;利用电压稳定分岔分析方法,同时运用时域仿真和混沌理论作为补充,对多种负荷状态下电力系统的电压失稳过程和机理、电压稳定域、负荷裕度和功率传输极限进行了全面分析;在此基础上,分别基于有限时稳定原理和对角矩阵的渐进稳定原理设计了两种非线性电压稳定控制器,并通过数值仿真验证了控制器的有效性。首先,对传统单机-PQ动态负荷电力系统模型进行改进,考虑系统受到电磁功率扰动、具有两个不确定参数且由静止无功补偿器(SVC)支撑电压;将无功补偿增益k_(SVC)和系统无功负荷Q_d作为分岔参数(即不确定参数),利用分岔理论和混沌理论分析系统的一维平衡解流形(即电压曲线)和时域仿真图,得出了系统从电压失稳到崩溃的物理机理;利用系统的二维分岔曲线,分析了多参数变化下系统的电压稳定运行极限、无功负荷裕度和SVC增益调节裕度;最后利用有限时稳定控制原理进行控制器设计,实现了系统的非线性电压稳定控制。其次,考虑系统具有三个不确定参数,对含Walve动态负荷的单参数电力系统模型进行重新推导,得到以P_1、Q_1和P_m为未定参数的数学模型;利用系统的电压曲线、相轨迹、最大LE谱和分岔图,综合分析该系统在多种负荷情况下的电压稳定特性及系统运行状态变化;对系统进行双参数、三参数电压稳定分析,得到了系统的电压稳定边界、功率传输极限、负荷动态特性等。最后,提出基于对角阵的渐进稳定原理的控制思路,设计了一种新型非线性电压稳定控制器,经Matlab仿真验证,该控制器能够有效抑制电力系统的电压失稳现象,提高系统的电压稳定性,且具有较强的鲁棒性。
[Abstract]:With the development of industry and information technology in the 21st century and the continuous improvement of people's living standard, industrial production equipment, household appliances and other power supply quality are constantly put forward higher requirements, how to provide more security and stability, Reliable power supply has become the research direction of modern power system related technology. The quality of power system is measured by voltage, frequency and harmonics. As several voltage instability accidents in the world have seriously affected the production and life of the society and people at that time, in recent years, the voltage stability of the power system has attracted the attention of the society and the International Electrotechnical Institute. With the continuous progress of power industry, modern power system is increasingly developing towards the direction of large power grid, large units, UHV long-distance transmission, the use of various distributed power sources, new energy grid connection and reactive power compensation, etc. The operation conditions of power system are becoming more and more complex and the dynamic factors are increasing, which makes it more difficult to maintain the voltage stability of the power network. In this context, various uncertain factors and dynamic effects such as dynamic load, dynamic characteristics of reactive power compensator, dynamic characteristics of generator and electromagnetic power disturbance are considered in this paper. Two different power system models are improved respectively. Using the method of voltage stability bifurcation analysis and using time domain simulation and chaos theory as a supplement, the voltage instability process and mechanism of power system under various load conditions and voltage stability region are studied. The load margin and power transmission limit are analyzed. On this basis, two kinds of nonlinear voltage stability controllers are designed based on the finite time stability principle and the diagonal matrix asymptotic stability principle, respectively, and the effectiveness of the controller is verified by numerical simulation. Firstly, the traditional single-machine PQ dynamic load power system model is improved, considering the electromagnetic power disturbance, the system has two uncertain parameters and is supported by the static Var compensator (SVC). Taking reactive power compensation gain k _ (SVC) and reactive load QD as bifurcation parameters (i.e. uncertain parameters), the one-dimensional equilibrium solution manifold (voltage curve) and time-domain simulation diagram of the system are analyzed by bifurcation theory and chaos theory. The physical mechanism of the system from voltage instability to collapse is obtained. The voltage stability limit, reactive load margin and SVC gain adjustment margin are analyzed by using the two-dimensional bifurcation curve of the system. Finally, the controller is designed based on the finite time stability control principle, and the nonlinear voltage stability control of the system is realized. Secondly, considering that the system has three uncertain parameters, the single-parameter power system model with Walve dynamic load is rededuced, and the mathematical model with PSP _ 1Q _ S _ 1 and P _ S _ m as undetermined parameters is obtained. Using the voltage curve, phase locus, maximum LE spectrum and bifurcation diagram, the voltage stability characteristics and the operating state of the system under various loads are comprehensively analyzed. The voltage stability of the system is analyzed with two parameters and three parameters. The voltage stability boundary, power transmission limit and load dynamic characteristics of the system are obtained. Finally, a novel nonlinear voltage stability controller based on the diagonal matrix asymptotic stability principle is proposed. The Matlab simulation shows that the controller can effectively suppress the voltage instability in power system. The voltage stability of the system is improved and the system is robust.
【学位授予单位】：华北电力大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM712

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