Method for discriminating voltage instability and load angle instability based on thevenin equivalent

Abstract

The invention provides a method for judging power angle instability and voltage instability based on the dynamic Thevenin equivalence. When a power system fails and instable, and the voltage is greatly reduced, the system operation and analysts is difficult to judge whether the instable property of the system belongs to the power angle instability or the voltage instability. Based on the dynamic Thevenin equivalence method, the real-time variation of the Thevenin equivalent potential of a load node to be monitored after the failure occurs can be obtained; and compared with the Thevenin equivalent potential, the instable property of the system can be judged. The method can be applied to the on-line analysis control and the off-line emulation analysis of the power system, facilitate the system operation and the analysts to adopt the effective measure in time and improve the safe and stable operation level of the power system.

Description

technical field [0001] The invention relates to a method for power system analysis, in particular to a method for judging power angle instability and voltage instability, and belongs to the field of power systems. Background technique [0002] Power system stability refers to the ability of the power system to maintain stable operation after being disturbed by accidents. Power angle stability and voltage stability are two important aspects of the stability problem. At present, the research on power angle stability is relatively mature, and a relatively complete analysis and control system has been formed. However, the research on voltage stability is still in the development stage from the concept to the analysis method, and the corresponding research work is far from being mature. At present, there is no unified standard for the criterion of voltage instability. The standard adopted in engineering in my country is based on the magnitude and duration of the bus voltage dro...

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Problems solved by technology

[0003] In engineering off-line simulation analysis, it is more recognized at present to judge whether it is power angle instability or voltage instability through the effectiveness of control measures, but this method has not yet been clearly explained from the mechanism, and its correctness needs further research. Demonstration, and not suitable for online analysis and control of power systems

In the on-line operation analysis and control of the power system, from the existing literature and actual engineering systems, when the system voltage drops sharply after a fault, there is no real-time indicator for judging the nature of the system instability, so that the system dispatcher can use What kind of effective control measures to restrain the further deterioration of system instability has brought confusion, lost the best time to save the system, led to further deterioration of system instability, and even system collapse, the social impact and economic losses it brought are immeasurable

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