On the nature of unstable equilibrium points in power systems
- Royal Inst. of Tech., Stockholm (Sweden). Dept. of Electric Power Systems
This paper concerns the application of direct methods for transient stability analysis of stressed power systems. One of the most important issues in this area is to find the controlling unstable equilibrium point for the disturbance under consideration. This paper provides a conceptual framework for discussing stable and unstable equilibrium points in power systems based on simple topological arguments. It is for instance shown that every conceivable case of system separation can be related to a specific unstable equilibrium point (u.e.p) in an unloaded system. This result can be seen as a verification of the soundness of the often used corrected corner point approximation and ray point approximation, since these two approximations would give the same unstable equilibrium points in an unloaded system. Moreover, it is shown, by an example, that some of these unstable equilibrium points can disappear when the loading of the system increases. The implications of the findings of this paper are discussed for the so-called MOD method of finding the controlling u.e.p., which is used in some software packages. Finally, a method based on a combination of MOD method and the BCU method is outlined and proposed as the subject of future investigation.
- OSTI ID:
- 6109264
- Journal Information:
- IEEE Transactions on Power Systems (Institute of Electrical and Electronics Engineers); (United States), Journal Name: IEEE Transactions on Power Systems (Institute of Electrical and Electronics Engineers); (United States) Vol. 8:2; ISSN ITPSEG; ISSN 0885-8950
- Country of Publication:
- United States
- Language:
- English
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