• 대한전기학회논문지:전력기술부문A
• /
• 제55권12호
• /
• pp.514-521
• /
• 2006

The existing ULTC operation control strategy based on the measured data deteriorates the voltage compensation capability making the efficient corresponding to the load variation difficult by following the fixed load center point voltage. Accordingly, this paper proposes a new on-line fuzzy ULTC controller based on the designed multiple load center points which can improve the voltage compensation capability of ULTC and minimize voltage deviation by moving in real-time the load center point according to the load variation to an adequate position among the multiple load center points designed using the clustering technique. The Max-Min distance technique is adopted as the clustering technique for the decision of multiple load points from measured MTr load current and PTr voltage, and the minimum distance classifier is adopted for the decision of fuzzy output membership function. To verify the effectiveness of the proposed strategy, Visual C++ MFC-based simulation environments is developed. Finally, the superiority the proposed strategy is proved by comparing the fuzzy ULTC operation control results based on multiple load center points with the existing ULTC operation control results based on fixed load center point using the data for three day.

• Structural Engineering and Mechanics
• /
• 제53권5호
• /
• pp.981-995
• /
• 2015

This paper presents a finite element procedure for dynamic analysis of non-uniform Timoshenko beams made of axially Functionally Graded Material (FGM) under multiple moving point loads. The material properties are assumed to vary continuously in the longitudinal direction according to a predefined power law equation. A beam element, taking the effects of shear deformation and cross-sectional variation into account, is formulated by using exact polynomials derived from the governing differential equations of a uniform homogenous Timoshenko beam element. The dynamic responses of the beams are computed by using the implicit Newmark method. The numerical results show that the dynamic characteristics of the beams are greatly influenced by the number of moving point loads. The effects of the distance between the loads, material non-homogeneity, section profiles as well as aspect ratio on the dynamic responses of the beams are also investigated in detail and highlighted.

• 한국전산구조공학회논문집
• /
• 제15권1호
• /
• pp.21-32
• /
• 2002

일반적으로 응답스펙트럼 해석법은 건물의 지진해석에 널리 사용되고 있지만 기계하중이나 이동하중 등에 의하여 발생하는 진동에 대한 해석에는 시간이력해석이 주로 사용되고 있다. 그런데, 시간이력해석법은 정확한 반면 매우 복잡하고 어려우며 많은 시간을 필요로 한다. 따라서, 본 논문에서는 동적하중을 받는 구조물의 최대응답을 응답스펙트럼해석법을 이용하여 간편하게 계산하는 방법을 제시하고자 한다. 우선, 이 해석법의 해석과정에 대하여 알아보았으며, 복수절점에 동적 하중을 받는 경우에 대해서 해석시간 및 메모리를 줄이는 방법을 제시하였다. 다음으로는 이동하중을 받는 경우에 대하여 구조물의 최대응답을 구하는 방법에 대하여 알아보았다. 마지막으로 예제를 통하여 시간이력해석을 수행하여 얻은 최대응답과 응답스펙트럼해석에 의한 최대응답을 비교하여 제시한 해석법의 정확성을 확인하였다.