부산대학교 도서관

An alternative modeling approach to detect the occurrence of inrush currents in power transformers is discussed. The inrush current phenomenon is affected by the core residual magnetization $J_{r}$ and voltage source initial phase , $\theta _{0}$ , through which a region in the $J_{r} - \theta _{0}$ plane where inrush currents do not occur (named inrush safety region—ISR) is defined. The approach is founded on the awareness that a fairly accurate description of the inrush process does not require a detailed description of the core magnetization process, leading to the employment of a piecewise linear (PWL) magnetization model, able to detect in a straightforward way the ISR. The main advantage of the approach is to set up a fast algorithm for ISR detection, suitable for real-time control. An accurate model of the transformer, based on a Preisach model (PM) magnetization algorithm has been exploited, along with a suitable set of experimental results allow to confirm the validity of the proposed identification approach.