Structure in Power System Analysis and Control

在以前的工作中，大型电力系统的数学结构作为有或没有硬极限存在的微分代数系统，已经在总体分类的背景下进行了研究。除了数学结构外，物理系统还具有广泛的物理结构，从非结构化到分层结构或非常严格的结构。大型电力系统模型具有很强的分段（网）结构。动态方程通常分成若干段（由电力系统中的总线物理定义），仅通过非动态关系（在网络中）捆绑在一起。这种地理结构在与控制有关的问题中变得非常重要。在这个项目中，随着数学理论的某些方面的完成，分类学理论将在控制问题的背景下研究分段系统，特别是在电力系统的控制方面。鉴于电力系统的地理结构，许多控制问题可以分散解决。例如，稳定控制问题可以表述为跟踪一个运动目标，该目标的每个部分都有一个分量，因此可以很容易地在局部计算。本文将分析这种观测解耦控制的全系统稳定性。电力系统的分段结构也导致了基于观察解耦单母线簇的基本簇的各种聚类方法。基于分类学理论对聚类控制方案进行分析。将研究各种控制方法的收敛性和准确性，并寻求各种情况下最理想的方法-例如快速，中速和慢速控制（任务）。快速控制目标大多与保持电力系统的稳定性有关。我们将其表述为跟踪移动目标向量的问题。这个目标很容易分解成相互关联的分段问题，并在跟踪成功时识别稳定的平衡点（注意，在大多数文献中方便忽略的干扰事实的时间尺度上识别平衡点是不切实际的）。然而，平衡点恰恰是在成功跟踪结束时找到的。这就需要设计有效的近似跟踪方案，从而在这种情况下得到精确的结果。然而，找到这样的跟踪方案并精确地确定它们的收敛性是很重要的。这将在项目中完成。针对自动发电控制（ACC）问题的中速控制很容易形成一个三层分段方案，既适用于传统的AGC（单个总线上的设备，与连接线路的单个电力公司称为区域的分段，以及由NERC在全国范围内设定所需频率），也适用于新的解除管制方案（发电站、国家输电公司和配电公司）。虽然需求是不同的，但结构上的相似性意味着理论中的联系。将对这些方案进行分析，并寻求最理想的方案。大系统的聚类将是这项工作的基础，包括彻底和精确的分析和技术开发。对状态参数空间内的可观测区和可控区等新的分类概念进行了定义和分析，其彻彻性和精确性与我们之前的分类工作相对应。电力系统的持续发展远离地方电力公司和监管连接AGC控制层的发电，输电和配电公司基于实时商品交易在全国范围内使得这项研究非常重要和潜在的非常有用。目前，将最终决定其控制需要的结构的改组后的系统的最后形状尚未出现。因此，分类法方法的灵活性可以适应各种各样的需要和结构，这将使它成为寻找最理想的结构和目标的理想工具。

ECS-9610049 Zaborszky In previous work the mathematical structure of the large power system as differential-algebraic system with or without the presence of hard limits has been studied in the context of an overall taxonomy. Along with their mathematical structure, physical systems have a wide spread of physical structure ranging from unstructured to hierarchical or very strict structures. The large power system model has a very strong segmental (network) structure. The dynamic equations typically separate into segments (which are physically defined by the buses in the power system), tied together only through non-dynamic relations (in the network). This geographic structure becomes of great importance in questions related to control. In this project, along with completing certain aspects of the mathematical theory, the taxonomy theory will be studied for segmental systems in the context of control problems, specially in the control of power systems. In view of the power system's geographic structure many control problems can be addressed decentralized. For instance, the problem of stabilizing control can be formulated as tracking a moving target which has a single component for each segment and thus can be easily computed locally. The systemwide stability of such an observation decoupled control will be analyzed. The segmental structure of the power system also leads to various clustering approaches built on rudimentary clusters of observation decoupled single bus clusters. Clustered control schemes will be analyzed on the basis of the taxonomy theory. The convergence and accuracy of various control approaches will be studied and the most desirable approaches for various circumstances-such as fast, medium and slow control (tasks) will be sought. The fast control objectives are mostly connected to preserving the stability of the power system. We have formulated it as a problem of tracking a moving target vector. This objective readily breaks up into interconnected segmen tal problems and identifies the stable equilibrium point when the tracking is successful (note that it is not practical to identify the equilibrium on the time scale of the disturbances fact conveniently ignored in most of the literature). However, the equilibrium is found precisely at the end of successful tracking. This invites the design of effective approximate tracking schemes which lead in this case to precise results. It is important, however, to find such tracking schemes and establish precisely their convergence. This will be done in the project. The medium fast control for the problems of the automatic generation control (ACC) readily settles into a three layer segmented scheme both for the traditional AGC (equipment at individual buses, segments called Areas for individual power companies connected with tie lines and nationwide setting of desired frequency by NERC) and the new deregulated scheme (generating stations, national transmission company and distribution companies). Although needs are different, the structural similarity implies connections in the theory. These will be analyzed and the most desirable schemes sought. Clustering of the large system will be the basis of this work involving thorough and precise analysis and technique development. New taxonomy concepts such as observability region and controllability region within the state-parameter space will be defined and analyzed at the thoroughness and precision corresponding to our earlier Taxonomy work. The ongoing development of the power system away from local power companies and regulation connected AGC control to layers of generation, transmission and distribution companies based on a real time commodity trading nationally makes this proposed study quite important and potentially very useful. At present the final shape of the reorganized system which will eventually dictate the structure of its control needs is not yet emerging. Hence the flexibility of the taxonomy approach which can accommodate a grea t variety of needs and structure will make it an ideal vehicle for searching for the most desirable structures and objectives.