Dissertation
Synchrophasor Based Voltage Stability Assessment And Local Volt/VAR Control Of Power Systems
Doctor of Philosophy (PhD), Washington State University
01/2017
Handle:
https://hdl.handle.net/2376/112610
Abstract
Among several power system blackouts in recent decades, such as the events on July 2, 1996 in the western American system and August 〖14〗^th 2003 in Northeastern American system, voltage instability was one of the major causations due to the aging transmission networks, increasing competitions among power utilities, and emerging power market regulations, etc. Voltage stability monitoring in real time has always remained a major concern both in industry and academic research. To maintain the voltage stability and keep optimal voltage levels in daily power system operations, the coordinative control of reactive VAR resources plays a key role. This dissertation targets on the development of Synchrophasor based algorithms for the following two topics 1) Voltage stability assessment and 2) Automatic local Volt/Var control.
The first part of this research starts from the discussion of the distributed voltage stability monitoring tool, implemented at several power utilities, based on Q-V sensitivities. Then, a new algorithm based on the estimated pseudo-Jacobian is proposed and developed for use at control centers. Assuming PMU is available on each bus in a power system, the method provides the indication of global voltage stability status and the location of non-linear events occurred in the system. Several IEEE test systems under different loading and generator event scenarios are used to test the method and the results have been validated with established analytical tools.
An automatic close-loop voltage controller is presented as the second part of this dissertation. The objective of this controller is to develop a local control tool that automatically operates only discrete VAR devices to maintain daily voltages within optimal bands at substation level. The proposed controller is formulated purely independent of the full state estimator model and can be applied to any subsystem or subareas in a large power system. A multi-port external equivalent model is proposed based on local PMU measurements as a local power flow tool to approximate switching effects of discrete control devices. The controller solves the optimal multiple switching problem as a multi-objective optimization at different operating phases using time varying dynamic programming algorithm.
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Details
- Title
- Synchrophasor Based Voltage Stability Assessment And Local Volt/VAR Control Of Power Systems
- Creators
- Xun Zhang
- Contributors
- Vaithianathan Venkatasubramanian (Advisor)Anjan Bose (Committee Member)Anurag K. Srivastava (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- School of Electrical Engineering and Computer Science
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 125
- Identifiers
- 99900581516801842
- Language
- English
- Resource Type
- Dissertation