| Fractal geometry is one of the most important discoveries of mathematical science. Nowadays fractal techniques are widely used in natural and social science. This paper discusses some application of fractal in non-solidly earthed network and voltage sags from the following aspects:Firstly, fault line identification and fault location in non-solidly earthed network have been studied. The zero-sequence equal model of single-phase-to-earth fault is built on the basis of distributed parameter lines. The different transient characteristics between normal line and fault line are given by analyzing non-solidly earthed networks, which include point unearthed system, the neutral point through big-resistance system and the neutral point through extinction coil system. And by frequency spectrum analyzing of the signal, the RS-dimension's criterion of fault line identification and the RS-dimension's formulas of fault location are given. At last, various faults under different conditions are simulated, which show that the method is feasible and effective.Secondly, voltage sags in power quality has been studied. Voltage sags has been one of the most important serious power quality problems,in which the time from declining to inclining and the amplitude of voltage are looked as the two important parts. During the declining of voltage, the voltage's amplitude has declined apparently and the higher frequencies have been included. The time from declining to inclining can be analyzed by the RS dimension, which enhances the detection accuracy and speed which is very useful for the compensation device. And the declining amplitude of voltage sages can be analyzed by virtual value's calculation.In this paper,fractal, especially RS dimension has used in analyzing the fault line identification and fault location in non-solidly earthed network, and analyzing voltage sages, which is a new method to those questions and is the base for RS application in the power system's many aspects in the coming future.
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