【作者】 石颉；

【导师】 王成山；

【作者基本信息】 天津大学 ， 电力系统及其自动化， 2007， 博士

【摘要】 本文针对制约大型互联电网跨区域送电能力提高的主要障碍——区域间低频振荡问题,在考虑广域信号传输时延的前提下,提出了几种基于同步相量测量单元(Phasor Measurement Unit,PMU)及广域测量系统(Wide-Area Measurement/ Monitoring System,WAMS)的广域阻尼控制器的设计方法,为提高大型互联电力系统的动态性能进行了有益的探索。(1)提出了一种基于进化策略的广域电力系统稳定器(PSS)设计方法。较为详细的分析了时延对系统稳定性的影响,并提出了时延的处理方法,使闭环系统变为不显含时延项的控制系统,并应用进化策略整定PSS参数。所得PSS控制器使系统的最大允许时间延迟增大,增强了系统对时延的鲁棒性。该方法能使控制系统不显含时延,从而可用无时延的分析与设计方法对系统进行分析。(2)提出了基于H∞回路成形技术的广域H∞控制器的设计方法。由于实际电力系统中不可避免的存在多种不确定性,提高电力系统控制器的鲁棒性能成为一个重要的课题。文章在考虑广域信号传输时延的情况下,对开环电力系统状态空间模型,应用回路成形技术使线性化的开环电力系统模型具有期望的特性,采用规范互质分解理论对成形后的摄动系统模型进行鲁棒镇定控制器设计。与不考虑时延设计的控制器相比,该控制器不仅具有很好的阻尼特性及鲁棒性能,同时能使闭环系统容忍更大的时延。(3)提出了基于线性矩阵不等式(LMI)理论的电力系统广域状态反馈控制器的设计方法。考虑到时滞系统控制精度的要求,有必要建立精确的显含时延项的数学模型(时滞系统模型)。另一方面,权函数的选择一直是H∞控制器的设计难点。文章根据实际电力系统的特点构造了部分状态含时延的广域状态反馈控制器,应用线性矩阵不等式理论提出了时滞依赖的稳定性条件,并对该问题进行了求解。根据该条件不仅能得到一组保证系统稳定的控制器,而且可以得到保证系统稳定的最大允许时间延迟。与H∞控制器的设计方法相比,此方法克服了权函数的选择这一难题,在方法上更具优越性。更多还原

【Abstract】 The inter-area low frequency oscillation is a dominating obstacle to limit the enhancement of transfer capability between different areas of interconnected power system. In this dissertation, three approaches to design power system damping controller based on the Phasor Measurement Unit and Wide-Area Measurement/ Monitoring System have been proposed, and remote signals’delay was considered. Those approaches provide some new views on improvement for the dynamic performance of interconnected power system.(1) A new approach to design the wide-area PSS, that is the PSS with remote input signals, based on the evolutionary strategy is proposed. Delay’s impact on stability of power systems is analysed in details, and pade approximation is used to express the time delay. By this way, the close loop system turns into implicit about time delay. The locations of PSS and feedback signals are chosen according to residue matrix. Finally, evolutionary strategy is used to coordinate the PSS parameters. Those PSS can increase the maximum allowable time delay and the robustness on time delay is enhanced. This method can make the control system implicit on time delay, so the analysis and design theory unrelated to delay can be used.(2) A new method to design the wide-area H∞controller based on the H∞loop-shaping theory is proposed. In fact, diversified uncertainties exist widely in the power systems. How to improve the robustness of the controller has been a topic issue. The open-loop power systems model is built with consideration of the remote signal’s time delay, which is replaced by Pade approximation. Then the model is shaped to give desired open-loop properties at interested frequencies and the shaped plant is robustly stabilized using the normalized coprime factor approach of H∞optimization. The realized controller is not only robust but also endurable for larger time delay.(3) A new type of state feedback controller, named wide-area state feedback controller, with consideration of remote signals’time delay, is designed based on the LMI theory. To take into consideration of the precision of time-delay system, it is useful to build the model with exact time delay. On the other hand, Choice of weight function is a difficult problem of H∞controller design. In this dissertation, the state feedback controller with partial delay states, which are far beyond the local states in distance, is constructed. A new delay-dependent stability condition is deduced with linear matrix inequalities (LMI) theory and the LMI toolbox of MATLAB can be used to optimize the solution. By this condition, a group of controllers can be achieved and the maximum allowable time delay can be calculated. By this approach, choice of weight function was avoided. In this sense, it is better than the method based on H∞theory.更多还原