Dissertation
Design of wide-area damping control systems for power system low-frequency inter-area oscillations
Washington State University
Doctor of Philosophy (PhD), Washington State University
12/2007
DOI:
https://doi.org/10.7273/000005773
Abstract
The recently developed robust control theories and wide-area measurement
technologies make the wide-area real-time feedback control potentially promising. The
objective of this research is to develop a systematic procedure of designing a centralized
damping control system for power grid inter-area oscillations by applying wide-area
measurement and robust control techniques while putting emphasis on several practical
considerations.
The first consideration is the selection of stabilizing signals. Geometric measures
of controllability/observability are used to select the most effective stabilizing signals and
control sites. Line power flows and currents are found to be the most effective input
signals. The second consideration is the effects of time-delay in the communication of
input/output signals. Time-delays reduce the efficiency of the damping control system. In
some cases, large delays can destabilize the system. Time-delays should be modeled in
the controller design procedure so that the resulting controller can handle a range of timedelays.
In this work, time-delays are modeled by Padé Approximations and the delay
uncertainty is described by Linear Fractional Transformations (LFT). The third
consideration is the controller robustness. The synthesis of the controller is defined as a
problem of mixed H2/H∞ output-feedback control with regional pole placement and is
resolved by the Linear Matrix Inequality (LMI) approach. The controller designed by
robust control techniques has satisfactory performance in a wide range of operating
points. The fourth consideration is the efficiency of the controller designed by linear
techniques in realistic nonlinear discrete environments. A tuning process and nonlinear
simulations are used to modify the controller parameters to ensure the performance and
robustness of the controller designed with linear techniques. The last consideration is the
selection of PMU data reporting rates. The performance of controllers designed in the sdomain
is tested in digital environments and proper PMU data reporting rates are selected
with consideration of the effects of time-delay.
The design procedure of wide-area damping systems is illustrated by three study
systems. The first study system is a two-area four-machine system. The second one is the
New England 39-bus 10-machine system. The last one is a 29-generator 179-bus study
system, which is a reduced order model of the Western Electricity Coordinating Council
(WECC) system.
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Details
- Title
- Design of wide-area damping control systems for power system low-frequency inter-area oscillations
- Creators
- Yang Zhang
- Contributors
- Anjan Bose (Chair) - Washington State University, School of Electrical Engineering and Computer ScienceKevin Tomsovic (Committee Member)Vaithianath Venkatasubramanian (Committee Member) - Washington State University, School of Electrical Engineering and Computer Science
- Awarding Institution
- Washington State University
- Academic Unit
- School of Electrical Engineering and Computer Science
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 177
- Identifiers
- 99901054762001842
- Language
- English
- Resource Type
- Dissertation