基于概率法的风电并网系统小干扰次同步相互作用分析与抑制研究

发布时间：2018-04-20 08:19

本文选题：双馈风电机组(DFIG) + 直驱式永磁同步风电机组(PMSG)　；参考：《上海电力学院》2017年硕士论文

【摘要】：近些年,我国风电得到快速发展,由于风资源丰富的地方远离负荷中心,在大规模远距离输电工程中,常用串补电容提升输电线路的传输能力,当串补度不合适或系统的运行方式发生变化时可能会引起次同步相互作用(sub-synchronous interaction SSI),导致风机脱网,使系统变得不稳定。由于风电出力的随机波动性,本文基于概率法研究了风电并网系统的次同步相互作用及抑制措施,研究内容主要包括以下几个部分:(1)利用插入式建模技术(PMT)搭建了风电串补系统完整的小干扰分析模型,包含双馈和直驱风力发电机组、同步发电机组、负荷、静止无功补偿器(SVC)及附加阻尼控制模型等。利用概率法结合李雅普诺夫第一法求得特征根的概率属性,分析次同步模式的振荡特性。(2)由于系统运行方式的变化会影响次同步相互作用,本文考虑了风机出力和同步机出力的不确定性以及负荷随机波动的系统多运行状态,提出概率特征根分析法求得次同步振荡模式的统计属性,判断多运行方式下次同步模式的概率稳定性。通过算例系统仿真,结果表明风电场经串补线路并网会带来新的次同步振荡模式,利用参与因子和概率灵敏度对振荡模式进行识别,找出并分析与次同步振荡模式强相关的状态变量,为抑制措施的设计提供基础。(3)分析了次同步相互作用的作用机理,以及串补度和风机类型的不同对次同步概率稳定性的影响,提出概率灵敏度指标(PSI)分析变频器控制参数对次同步模式的影响,在此基础上,提出在变频器加装电力系统稳定器(PSS),利用风电机组参与SSCI抑制。对DFIG-PSS最佳安装位置进行定位,并选择最优的输入信号。选取PSS参数并利用概率灵敏度矩阵进行优化以改善次同步振荡的抑制效果。(4)结合概率方法提出SVC附加阻尼控制的抑制措施,通过多机系统算例仿真,对比加装抑制措施前后阻尼常数和阻尼比的概率密度曲线,次同步概率稳定性得到改善,并通过时域仿真验证该抑制措施的有效性。
[Abstract]:In recent years, wind power in China has been developing rapidly. Because wind resources are abundant in places far from load center, series compensation capacitors are commonly used to enhance transmission capacity of transmission lines in large-scale long-distance transmission projects. When the series compensation degree is not suitable or the operation mode of the system changes, it may cause sub-synchronous interaction and sub-synchronous interaction SSI, which will result in the blower being off the grid and the system becoming unstable. Because of the random fluctuation of wind power output, this paper studies the sub-synchronous interaction and suppression measures of wind power grid connected system based on probability method. The main contents of the research include the following parts: 1) A complete small disturbance analysis model of wind power series compensation system is built by using plug-in modeling technology (PMTT), which includes doubly-fed and direct-drive wind turbines, synchronous generators, loads, etc. Static Var compensator (SVC) and additional damping control model. The probability attribute of the characteristic root is obtained by using the probabilistic method combined with Lyapunov's first method, and the oscillation characteristic of the sub-synchronous mode is analyzed. In this paper, considering the uncertainty of blower output force and synchronous generator output force and the multi-operation state of the system with random load fluctuation, a probability eigenvalue analysis method is proposed to obtain the statistical properties of the sub-synchronous oscillation mode. The probabilistic stability of the next synchronization mode is judged. The simulation results show that the wind farm will bring about a new sub-synchronous oscillation mode through series-compensated lines, and the participation factor and probability sensitivity are used to identify the oscillation mode. The state variables which are strongly related to the sub-synchronous oscillation mode are found and analyzed. The mechanism of the sub-synchronous interaction and the influence of the series compensation degree and the fan type on the stability of the sub-synchronous probability are analyzed, which provide the basis for the design of the suppression measures. The probabilistic sensitivity index (PSI) is presented to analyze the influence of frequency converter control parameters on the sub-synchronous mode. On this basis, it is proposed that the power system stabilizer is installed in the frequency converter and the wind turbine is used to participate in the SSCI suppression. Locate the optimal installation position of DFIG-PSS and select the optimal input signal. PSS parameters are selected and optimized by using probability sensitivity matrix to improve the suppression effect of sub-synchronous oscillation. Combined with probability method, the suppression measures of SVC additional damping control are proposed. The simulation results of multi-machine system are given. Compared with the probability density curves of damping constant and damping ratio before and after adding the suppression measures, the sub-synchronous probability stability is improved, and the effectiveness of the suppression measures is verified by time domain simulation.
【学位授予单位】：上海电力学院
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM614

【参考文献】