Showing papers by "Chen-Ching Liu published in 1986"
TL;DR: In this paper, an expert system is developed to assist in the decision-making of the reactive power/voltage control problem, and empirical rules are used to generate appropriate control actions when slight voltage violations occur.
Abstract: An expert system is developed to assist in the decision-making of the reactive power/voltage control problem. The knowledge required to perform the task is identified. To alleviate a voltage problem, empirical rules are used to generate appropriate control actions when slight voltage violations occur. Controls such as shunt capacitors, transformer tap changers and generator voltages are utilized. Theoretical justification of the empirical rules is presented. When it is judged that the voltage problem is so severe that empirical judgements may not be reliable, the developed expert system can help in formulating the problem so that an available application software package can be effectively utilized. In this paper, production rules are proposed to perform the above functions. Numerical examples are also presented.
185 citations
TL;DR: Numerical testing indicates that the algorithms proposed to expand the initial region produces nearly maximal security regions, which provides a systematic way to deal with practical issues such as the size of security regions and computational efficiency.
Abstract: This paper presents a method to compute maximal steady-state security regions based on the DC load flow model. The proposed method consists of three steps. First, an initial region (hyperbox) is obtained explicitly using an analytic method. A developed algorithem is then utilized to expand the upper and lower bounds of the initial region in as many dimensions as possible. The algorithm is based on a necessary and sufficient condition for a region to be secure. Due to the proposed condition, the algorithm is computationally very efficient. Finally, the expanded security region is used to initiate a set of optimization problems, which can be solved to yield maximal regions. Applications of security regions to power system planning and operation are discussed. Numerical testing indicates that the algorithms proposed to expand the initial region produces nearly maximal security regions. The results of the paper provide a systematic way to deal with practical issues such as the size of security regions and computational efficiency.
64 citations