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Título: Mechanizing dynamic security analysis
Autores: Marceau, Richard J.
Fecha: 1993
Publicador: McGill University - MCGILL
Fuente:
Tipo: Electronic Thesis or Dissertation
Tema: Engineering, Electronics and Electrical.
Engineering, System Science.
Descripción: The object of software frameworks is to mechanize human processes in order to accomplish high-level tasks that call upon diverse software tools. This thesis describes the ELISA framework prototype which performs power-system dynamic security analysis in the operations planning environment. ELISA mechanizes routines traditionally carried out by experts that are essential to power-system dynamic security analysis, greatly accelerating the realization of complex processes. Typically, ELISA executes appropriate load-flow and transient-stability simulations (i.e. using commercially available simulation software), performs result analysis, identifies and executes changes to the input and repeats this process until a user-defined goal, such as finding transient stability transfer limits, has been achieved.
A taxonomy of dynamic security analysis in operations planning is proposed employing the semantic net, class-object-property and rule paradigms. All of these are required to cover the full spectrum of knowledge found in the high-level goals, the process details, the complex conditional structures and the acceptance criteria which characterize dynamic security analysis. This taxonomy also describes the language of operations planners, defining not only the features presently supported by ELISA, but also providing a roadmap to future enhancements. Typical sensitivity studies are presented using a 700-bus production model of the Hydro-Quebec network to illustrate the considerable leverage afforded from using ELISA-like software.
In addition, the thesis addresses the issue of how such tools can assist in performing research to improve our understanding of fundamental power systems behaviour. Using the ELISA prototype as a laboratory test bed, it is shown that the signal energy E of a network's transient response acts as a barometer to define the relative severity of any normal contingency with respect to power generation or transfer P. For a given contingency, as P is varied and the network approaches instability, signal energy increases smoothly and predictably towards an asymptote which defines the network's stability limit: This limit, in turn, permits us to compare the severity of different contingencies. This behaviour can be explained in terms of the effect of increasing power on the damping component of dominant poles, and a simple function is derived which estimates network stability limits with surprising accuracy from two or three stable simulations.
As a corollary to this, it is also shown that a network's transient response can be screened for instability using a simple frequency-domain criterion. Essentially, this criterion requires performing the Fourier transform of a network's transient voltage response at various monitoring locations: When P is varied and the network goes beyond its stability limit, the angle of the Fourier transform's polar plot fundamentally changes its behaviour, passing from a clockwise to a counterclockwise rotational behaviour about the origin. This is confirmed by results obtained from performing stability-limit searches on the Hydro-Quebec system. Used in conjunction with signal energy analysis for determining stability limit proximity, this criterion can be quite useful for mechanized security-limit-determination tools such as ELISA.
Signal energy limit estimation and the proposed stability criterion are shown to be applicable to all normal contingencies and these results hold not-withstanding the presence of many active, nonlinear elements in the network.
Idioma: en