IEEJ Transactions on Power and Energy
Online ISSN : 1348-8147
Print ISSN : 0385-4213
ISSN-L : 0385-4213
A Voltage Stability Index based on Load Equilibration Force
Masato Yamamoto
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1998 Volume 118 Issue 4 Pages 467-476


The electrical data such as bus voltage, bus and line load flow acquired from a power system does not imply the stability of the system voltage. Accordingly, a proper index is needed to seize it.
This paper proposes a new voltage stability index based on the equilibration force of load which enables the load to operate steadily, using load admittance. The index is composed of the characteristics of load and power system, and expresses ideal state by the value 1, critical state by 0. The index value between these border values represents stability extent, therefore, this index is possible not only to detect the critical state, but also to expresses the degree of stability. The computation of this index is consist of load flow calculations at the conditions of two specified load demands in the vicinity of each other and the index formula. It is more compact than the calculation of other indices formerly proposed.
Owing to above mentioned features, the proposed index would be useful in the field of on-line monitoring, contingency analysis and screening of multiple cases analysis for power system planning and operations.

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