1990 Fiscal Year Final Research Report Summary
System Development for on-Line Evaluation of Power Systems Through a Non-Lure Type Lyapunov Function
| Project/Area Number |
63550219
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
電力工学
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| Research Institution | University of the Ryukyus |
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Principal Investigator |
MIYAGI Hayao Univ. of the Ryukyus, Faculty of Eng., Professor, 工学部, 教授 (40112445)
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| Co-Investigator(Kenkyū-buntansha) |
YAMASHITA Katsumi Univ. of the Ryukyus, Faculty of Eng., Associate Professor, 工学部, 助教授 (60158152)
UEZATO Katsumi Univ. of the Ryukyus, Faculty of Eng., Professor, 工学部, 教授 (70045029)
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| Project Period (FY) |
1988 – 1990
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| Keywords | Non-Lure type Lyapunov function / Transient stability / Power system / On-line evaluation system / Robust stability / Phase measurement / Product-type nonlinear system |
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| Research Abstract |
1. The flux decay causes a product-type nonlinearity in the formulation of the electrical power output, and the conventional Lure-type Lyapunov function can not be well adapted for such a product-type nonlinear system. This report presents a way of constructing extended Lyapunov function for the product-type nonlinear system.
2. The report proposes a method of analyzing robust stability of nonlinear system through the direct method of Lyapunov, in order to cope with both ambiguity of the system parameters due to successive variation of power system loads and estimation errors in the system identifications.
3. The main factor which affects on the power system stability is synchronous machine. Then, in this report, methods are presented for analyzing hunting and pulling-into-step phenomena and improving the synchronization of synchronous machines, utilizing Lyapunov functions.
4. A useful method for improving stability of power system is on-off control utilizing damping resistor. This report gives a way of deciding optimal on-off timing of the resistor, using Lyapunov function.
5. In order to realize the on-line evaluating system for power system stability, the state variable such as phase angle of generator must be measured. This research has made a trial production of a measuring device of phase angle of generator.
6. A microcomputer-based on-line transient stability evaluation system for power systems using a non-Lure type Lyapunov function has been accomplished in the report. The Lyapunov function is constructed by the Lagrange-Charpit method. A software for controlling power system has also been developed. The experimental results show that this evaluation system can act satisfactorily for controlling stability of power system.
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