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Making the Most out of Distributed Generation without Endangering Normal Operation: A Model-Based Technical-Policy Approach.

机译：在不危及正常运行的情况下，充分利用分布式发电：一种基于模型的技术-策略方法。

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摘要

In this dissertation we introduce a model-based approach for efficiently locating and operating distributed generation (DG) without endangering stable system operation. The proposed approach supports quantifiable policy making based on technical design. The model used is structural and it comprises local models of DGs and loads interconnected via distribution grid system. While similar model structure can be used to represent meshed transmission grids, identifying model properties unique to distribution systems sets the basis for interpreting power delivery losses as the key measure of the overall system efficiency. It furthermore sets the basis for designing decentralized control specifications necessary to ensure system-wide stability. Once the underpinnings of the technical design are understood, the findings are used to propose a model-based quantifiable policy design to support process of integrating and operating DGs in distribution systems.;One possible problem with optimal placement of DG units may be an overly high sensitivity of their response to even small perturbations from normal conditions. Therefore, a very efficient distribution system with optimally-placed DG units may not be robust in operations. In order to assess robustness of distribution energy systems with respect to small disturbances, we model distribution systems as dynamical systems. We show that because of the strongly coupled voltage/real-power interdependencies in power flows of distribution systems, it is no longer possible to use a decoupled real-power dynamic model which neglects the effects of voltage dynamics. This conclusion is a direct consequence of a non-negligible resistance-reactance ratio in distribution systems which differentiates them from the typical transmission systems. Therefore, only coupled models should be used for stability analysis and for control tuning of DGs in distribution systems.;Using such a dynamic model we show that distribution systems with high penetration of DG units can exhibit frequency- and/or voltage-instabilities when power plants have conventionally tuned control. Such instabilities are particularly pronounced when the DG units are electrically close. Gerschgorin circle theorem and participation factor-based methods are used to identify the main cause of instabilities as being the interactions of the local DG dynamics through the distribution power grid. Since the proposed dynamical model structure allows us to represent any type of DG plant and its local control, stability analysis can be performed for a general type of a DG using these methods to determine bounds on interactions between each specific DG and the rest of the system so that no interactions occur. These bounds are dependent on the machine type and parameters, the local control and the grid parameters. Some DGs may not have sufficient control as measured in terms of these bounds, and, these are the ones which require enhanced control to ensure system-level stability without unstable interactions, as discussed next.;The severity of dynamical problems in specific distribution systems with DGs depends on the technology and control of DGs and on the electrical distances between the DGs. Typical DGs are either synchronous machines or induction machines whose inertia may be much smaller than the inertia of large generators. Their local control may range from no control, through well-understood governor-excitation control of synchronous machines, through power electronically controlled inverters of synchronous and/or induction machine type DGs (power system stabilizers (PSS) and/or doubly fed induction machines (DFIG)).;In this dissertation we have studied stability problems in systems with DGs being small and/or medium size synchronous machines controlled by governor-excitation systems and/or by pitch control combined with PSS control. We assess possible instabilities in such systems when controllers are tuned on a stand-alone machine connected to the impedance representing the rest of the system (today's practice). We show that a more systematic fully decentralized, and, therefore, simple, control design proposed, in this dissertation, could stabilize synchronous machine-type DGs, such as diesel and hydro plants, without inverter control. Moreover, synchronous machine-type wind power plants can be stabilized in a decentralized way by combining advanced pitch control and/or PSS control. (Abstract shortened by UMI.).
机译：在本文中，我们介绍了一种基于模型的方法来有效地定位和操作分布式发电（DG），而不会危及稳定的系统运行。所提出的方法支持基于技术设计的可量化政策制定。所使用的模型是结构性模型，它包含分布式发电和通过配电网系统互连的负荷的局部模型。尽管可以使用相似的模型结构来表示网格化的输电网格，但识别配电系统特有的模型属性可将解释输电损耗作为总体系统效率的关键指标奠定基础。它还为设计分散控制规范奠定了基础，以确保系统范围内的稳定性。一旦了解了技术设计的基础，这些发现将用于提出基于模型的可量化策略设计，以支持配电系统中集成和运行DG的过程。; DG单元的最佳放置可能存在的一个问题可能是过高他们对正常情况下很小的扰动反应的敏感性。因此，具有最佳放置的DG单元的非常高效的分配系统在操作中可能不够鲁棒。为了评估配电能源系统相对于小扰动的鲁棒性，我们将配电系统建模为动力系统。我们表明，由于配电系统潮流中电压/有功功率之间的相互依赖关系很强，因此不再有可能使用去耦有功功率动态模型来忽略电压动力学的影响。这一结论是配电系统中电阻-电抗比不可忽略的直接结果，这使它们与典型的传输系统有所不同。因此，仅应使用耦合模型进行配电系统中的DG的稳定性分析和控制调整。使用这种动态模型，我们表明，当电力供应充足时，具有较高DG单元穿透性的配电系统会表现出频率和/或电压不稳定性植物具有常规调整的控制。当DG单元电气闭合时，这种不稳定性特别明显。 Gerschgorin圆定理和基于参与因子的方法用于确定不稳定的主要原因，这是通过配电网进行的局部DG动力学相互作用的结果。由于建议的动力学模型结构允许我们表示任何类型的DG工厂及其本地控制，因此可以使用这些方法对通用类型的DG进行稳定性分析，以确定每个特定DG与系统其余部分之间相互作用的界限这样就不会发生任何互动。这些界限取决于机器类型和参数，本地控制和电网参数。某些DG就这些界限而言可能没有足够的控制权，而这些是需要加强控制以确保系统级稳定性而又没有不稳定相互作用的控制权，如下所述。 DG取决于DG的技术和控制以及DG之间的电气距离。典型的DG是同步电机或感应电机，其惯性可能比大型发电机的惯性小得多。它们的本地控制范围可以从无控制，通过对同步电机的透彻理解的调速器励磁控制，通过同步和/或感应电机类型DG（电力系统稳定器（PSS）和/或双馈感应电机（在本文中，我们研究了由调速器励磁系统和/或变桨控制与PSS控制组合控制的DG为中小型同步电机的系统的稳定性问题。当控制器在连接到代表系统其余部分的阻抗的独立机器上进行调谐时，我们评估了此类系统中可能存在的不稳定性（今天的做法）。我们证明，本文提出的一种更系统的，完全分散的，因此简单的控制设计，可以在没有逆变器控制的情况下稳定同步电机型DG，例如柴油和水力发电厂。此外，通过组合高级变桨控制和/或PSS控制，可以以分散的方式稳定同步电机型风力发电厂。 （摘要由UMI缩短。）。

著录项

  • 作者

    Honarvar Nazari, Masoud.;

  • 作者单位

    Carnegie Mellon University.;

  • 授予单位 Carnegie Mellon University.;
  • 学科 Engineering General.;Engineering Electronics and Electrical.
  • 学位 Ph.D.
  • 年度 2012
  • 页码 113 p.
  • 总页数 113
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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