Contingency control strategies for modern power system under a heterogeneous simulation environment

Abstract

This thesis reports on my research study on developing analysis tools for studying power system contingencies such as voltage collapse phenomena. One significant contribution is to develop and implement the tools under a heterogeneous simulation environment. In this respect, Ptolemy is regarded as a suitable platform for the above mentioned study. Although Ptolemy is originally designed for use in signal and image processing, it is chosen because of the likeliness that its features can be plotted into the power system application area. For instance, existing computational modules developed in the form of synchronous dataflow (SDF) domain and discrete event (DE) domain can be made use readily. In the study, a PFLOW program designed for tracing the bifurcation manifold and determining the saddle-node bifurcation point of a power system is integrated into the Ptolemy for carrying out the envisaged contingency analysis. Making use of one main feature of the PFLOW program for calculating the voltage collapse and voltage stability margin, I focus my contingency analysis on problems relating to the voltage collapse due unscheduled outage and tripping of power system components. Flexible AC Transmission System (FACTS) devices are assumed to be available for implementing the envisaged contingency control strategies as presented in the latter Chapters. In short, layout of the development work can be seen from the following breakdown. Chapter 1 gives general information of the study including background and literature review in three main areas, namely, tools for analyzing power system contingencies, development of associated control strategies and use of the FACTS devices for improving the system performance. Objectives and scope of the study are stated after the detailed review. Chapter 2 presents general concept of the heterogeneous simulation environment and outlines its advantages for the proposed applications. Chapter 3 provides a theoretical framework for tackling the contingency problems. In particular, a single "nose" curve based continuation method is proposed to deal with the voltage collapse problem. The method working under PFLOW is plotted into the Ptolemy. Chapter 4 describes development and implementation of the FACTS device model and its control strategies using the PFLOW program. Chapters 5 and 6 are the core units of the thesis as they involve an important stage in which the developed C/C++ programs are integrated into the Ptolemy. A 32 bus system from CIGRE TF 38-02-11 (voltage collapse case on the northern part of Belgium in 1982) and 173 bus system are used to validate the proposed approach. Finally, Chapter 7 draws conclusion of the overall study and outline possible continuation of work in the future.