Sub-fractal structure of single partial discharge in an electrical tree

Abstract

A concept of sub-fractal structure - a fractal structure growing in a space with a fractal dimension (base-fractal) - was put forward to describe the shape of a single partial discharge in an electrical tree with a base-fractal dimension. A computer simulation model was proposed to study the relation between the sub-fractal and the base-fractal dimensions. The tree growth rate was suggested to be related to the difference between these two fractal dimensions.

Study on electrical characteristics of XLPE insulation of high voltage cable

“…Besides traditional phase distribution method, there are also other methods, such as Weibull distribution [8,9], shape, symmetry and correlation distribution [10] using statistical parameters analysis [11] which examines around twenty statistical parameters associated with PD distribution. After extracting the main features using known PD discharges, fractal parameters [12,13], neural network paradigms [14,15], fuzzy classification [16] and wavelet coefficients [17,18] are attempted to recognize the different types of PD. It is noted that the correlation between all the measured variables and the discharge processes is limited.…”

“…The measurement for light emission was reported using CCD camera and photomultiplier [79][80][81]. The parameters extracted for light emission images included: luminous quantity, length [82,83], intensity [81,[84][85][86], radial extent [79,87], area growth [12,[88][89][90][91], and fractal dimension [85,92].…”

“…De-noising on PD is implemented by this method [17,18,116]. Fractal geometry is used to describe the parameters associated with PD patterns [12,84,85]. The most normally used image is the three dimensional pattern of ( , , ) H q n ϕ , which provides the relationship between the phase, the discharge quantity and number of occurrence.…”

“…This assumption corresponds to a material in which the conductivity goes from a very small value to essential infinity at the space charge-limited field, i.e. the conductivity form as shown in equation (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20). For this assumption, the field on the surface of a stress enhancement is independent of the applied voltage.…”

“…In later calculation, XY plane is applied for field solution by "AC conduction" solver. The conventional method of measuring the permittivity is to use two parallel electrodes with a dielectric material sample inserted between the electrodes as illustrated in ε by equation (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17).…”