多機系統の過渡動揺時に適用する簡易位相検出システム

Abstract

In multimachine power system, there is very difficulty to measure the phase angle between each generators which distance is far away. In this paper, equivalent one machine to infinite bus system is applied and two methods to detect phase angle are showed. The first is equivalent reactance method, in which after the estimation of equivalent reactance of power system, this equivalent reactance is used to detect phase angle swing during transient time. Three models used to detect phase angle are compared concerning the approximation to the true value and the error of equivalent reactance is estimated. This method is effective in low and medium load state conditions. In heavey load state condition, the phase angle swing is largely disturbed by the reaction between generators, so the error in case of using equivalent reactance method is large. The second method based on observer theory with the equivalent reactance method jointly is developed. Equivalent nonlinear generator's model and two type of observed values (active power Pe or angle velocity ω) in the method are used to estimate the phase angle swing of generator. The result is that ω type's feedback has a bigger range than Pe type's feedback concerning feedback gain choosing. The method based on observer using the equivalent reactance has a good result specially in heavey load state condition compared with the first method using equivalent reactance method.