Dissertation
STUDY OF FORCED OSCILLATIONS AND NONLINEAR OSCILLATIONS IN POWER SYSTEMS
Doctor of Philosophy (PhD), Washington State University
01/2020
Handle:
https://hdl.handle.net/2376/112422
Abstract
The first part of this dissertation focuses on analysis of forced oscillations in power systems. If the frequency of a forced oscillation is close to that of a system natural mode, resonance will occur such that an oscillation with large magnitude will be seen in the power systems. Based on linearized power system model, a closed formula characterizing the oscillation magnitude amplification of system states with respect to forced oscillation source is derived. Furthermore, a method for estimating the overall impact of a forced oscillation is proposed when the forced oscillation frequency is close to the frequencies of multiple system modes. Harmonics effect from forced oscillation and the incurring challenges are studied. Among the methods for forced oscillation source location, the energy flow method has shown promising for detecting the source of a natural oscillation as well as a forced oscillation. This dissertation analyzes the performance of the energy flow method in depth by evaluating the expressions of incremental energy in one period of the forced oscillation and by looking at a wide range of forced oscillation frequencies. It shows a global view of how energy flow method performs under a wide range of forced oscillation frequency.
The second part of the dissertation focuses on nonlinearity in power system when one or two oscillatory modes get unstable, when Hopf and double Hopf bifurcations occur, respectively. This dissertation applies an efficient computational method for carrying out higher order center manifold and normal form calculations for a general power system model. It enables us to predict the birth or annihilation of limit cycles when Hopf bifurcation happens. Furthermore, this dissertation numerically calculates the normal form of a double Hopf bifurcation in power system model and performs a comprehensive analysis and unfolding of a scenario to show the complicated dynamics such as an oscillation with three frequency components.
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Details
- Title
- STUDY OF FORCED OSCILLATIONS AND NONLINEAR OSCILLATIONS IN POWER SYSTEMS
- Creators
- Yuan Zhi
- Contributors
- Vaithianathan Venkatasubramanian (Advisor)Anjan Bose (Committee Member)Sandip Roy (Committee Member)Krishnamoorthy Sivakumar (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Electrical Engineering and Computer Science, School of
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 135
- Identifiers
- 99900581811701842
- Language
- English
- Resource Type
- Dissertation