【作者】 袁世强；

【导师】 房大中；

【作者基本信息】 天津大学 ， 电力系统及其自动化， 2005， 硕士

【摘要】 现代电力系统在运行中必须满足能承受概率较大的单一故障扰动的要求。调度人员将通过预防控制措施将系统运行点从警戒状态转移到保持充裕性与安全性的正常状态。发电机有功出力重调整作为一种常见的预防控制手段,其调整方式的快速计算历来得到研究者的重视。早期直接法将线性度较好的暂态能量裕度用于求取暂态稳定极限,从而开辟了对这一领域的研究。考虑到分析精度,由混合算法开展暂态稳定预防控制更具吸引力。另外,与当前另一类研究思路——考虑暂态稳定性约束的最优潮流相比,本文选择的混合算法研究距离实际工程应用更为接近。本文首先简要回顾了直接法中暂态能量函数的定义与势能边界面法的物理背景,给出了一套实用的混合法分析策略。在此基础上详细分析了试验仿真中的最小动能特性,即严重受扰发电机有功出力与系统最小动能之间呈现两段近似线性的关系。其中斜率几乎为零部分对应于使系统保持暂态稳定的出力配置,最小动能完全体现为对失稳不起作用的无效动能;斜率较大的线段反映了系统将严重受扰发电机多余的出力转化为系统轨迹越过转子角空间中势能边界面时的动能,本文称为有效动能,它指示了致使系统失稳的多余能量;转折点对应于临界出力。为此,本文给出了一套方法用于确定系统严重受扰发电机、计算最小动能相对其有功出力的灵敏度,并结合混合算法求出的暂态能量裕度,迭代求解使系统保持暂态稳定的发电机出力极限以供调度人员参考。本文编写了程序实现该分析流程,并在新英格兰典型系统上进行多种运行方式与模型表示下的算例分析,验证了算法的正确性和可行性。最后论文给出了该方法可能的改进方向。更多还原

【Abstract】 Modern power systems in operation have to possess the capability to withstand a set of possible single contingencies. By means of preventive control, the operators will shift the current working status from the alert region to the normal one where adequacy and security are thus ensured. Generation rescheduling, as a common measure of preventive control, has been extensively addressed for a long time.The early works of direct methods utilized the quasi-linearity of transient energy margin (TEM) to approximate the transient stability limits, which opened an era of this area. As far as the precision is concerned, the hybrid method is much more appealing to conduct transient stability-constrained preventive control. Moreover, compared with another kind of approaches, namely optimal power flow with transient stability constraints, the hybrid method adopted in this thesis is more appealing to practical application.This thesis briefly reviews the definition of transient energy function (TEF) in direct methods and the physical concepts in potential energy boundary surface (PEBS) approach, followed by a viable strategy for hybrid method analysis. Based on these grounds the characteristics of minimum kinetic energy (KE) are expounded. Such a minimum KE comes from an energy trajectory of the post-fault system, and is quasi-linear with the mechanical input power of the severely disturbed machine in two distinct slopes. The segment with a small slope corresponds to the configuration where the power system stays stable; such a minimum KE is called inactive KE. The points on the declining segment match the extra energy that the system fails to convert to potential energy (PE) at the PEBS, which is called active KE. The inflexion of the two segments indicates the generation limit.To make use of this property, a methodology is put up implementing the following functions: to recognize the severely disturbed generators; to calculate the sensitivity of minimum KE with respect to the mechanical input power of these generators; to evaluate the TEM by a hybrid method; and finally, to combine them together in an iterative analysis framework.A computer program is compiled to implement such an algorithm. Multiple operation modes and representative models are employed on the 10-machine 39-bus更多还原