Abstract
This paper describes an optimal load-shedding policy based on quadratic programmings using only a part of state variables of the power system after severe generation outages. When a large amount of generation outage occurs, the imbalance between supply and demand powers causes a declining frequency. Generators of utilities can not be operated excessively beside off normal frequency. So a part of load must be shed to prevent the system's damages. So far, the optimal load-shedding policies have been studied using all of the state variables of power system. However, in the real power system operations, it is difficult to obtain remote informations in a fraction of a second after generation outages.
In this paper, firstly, an optimal load-shedding method is constructed using the Quadratic Programming (QP) under the assumption that all the state variables in a power system can be available. However, these state variables can not be easily accessible as mentioned above. Secondly, to cope with these difficulties, a suboptimal load-shedding scheme based on the local state variables is studied. The proposed load-shedding method is based on an ideal of the above mentioned optimal one. The change of line-power flows and the amount of the generation power outage are used as the accessible data at each load point. Incorporating these local informations into the optimal load-shedding method based on the QP method, the proposed load-shedding method is established in this paper.
The effectiveness of this proposed method is illustrated by two examples, and simulation results on a model power system show that the method is encouraging.
