A new RLC series-resonant circuit modeled by local fractional derivative

The local fractional derivative has gained more and more attention in the field of fractal electrical circuits. In this paper, we propose a new ?-order RLC** resonant circuit described by the local fractional derivative for the first time. By studying the non-differentiable lumped elements, the non-differentiable equivalent imped?ance is obtained with the help of the local fractional Laplace transform. Then the non-differentiable resonant angular frequency is studied and the non-differentiable resonant characteristic is analyzed with different input signals and parameters, where it is observed that the ?-order RLC resonant circuit becomes the ordinary one for the special case when the fractional order ? = 1. The obtained results show that the local fractional derivative is a powerful tool in the description of fractal circuit systems.

Influence Estimation of the On-Load Tap-Changing Transformeron the Currents in Schemes of Ice Melting on Overhead Transmission Lines

The influence of regulated under load transformer's (on-load tap-changing transformer) ratio and imped-ance on the short circuits’ currents and currents in the schemes of ice melting with AC and DC current is ana-lyzed. Accounting for changes in the transformer ratio is not difficult as it is provided in the technical data for all branches (tap positions). The transformer resistances used in the calculations, which are reduced to the un-regulated side of the transformer, are proportional to the short-circuit (SC) voltages. SC voltages are known, according to GOST, only for three tap positions - main (middle) and two extreme (top and bottom) positions, and for other tap positions are determined approximately according to different methods. It is shown on the typical example, that the error of the melting current calculation is significantly less than the error of the ap-proximated transformer's resistance calculation by the method of linear interpolation of resistances, the error of which for different types of on-load tap-changing transformers does not exceed 3 %.