| Abstract: | A novel algorithm for measuring the power system frequency during a very short time is presented in this paper, based on an approximate linear current amplitude model. The presented measuring frequency algorithm is used to get the instantaneous value of the parameter accurately. In the algorithm, the amplitudes of four consecutive sampled currents are supposed to be linear. After rigorous mathematical deduction, including Taylor series expansion and the geometric proportion theorem, the instantaneous frequency could be derived. The errors arising from the linearization in the model are analyzed qualitatively, and then the errors of A/D conversion and Taylor series expansion are considered. By the proposed technique, the measured frequency can be derived easily, quickly, and accurately, without any digital filters. The results after simulation show that the proposed algorithm has high accuracy and noise immunity during power swings and in the normal state. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. |
