Research on Frequency Characteristics of the Overhead Line Parameters

Having been learned a lot from the previous work , this paper proposed a new medium-frequency current ice-melting method employing skin effect and proximity effect phenomena to overcome the weaknesses of existing de-icing method of overhead line. By the interaction of the two phenomenon, the transmission line unit resistance is expected to increase, compared with the working frequency current, the intermediate frequency current with the same ice-melting power can be reduced effectively to protect the conductor. First, this paper set up a simplified ACSR model according to the Principle of Equivalence Area, and then the calculation of frequency characteristics of three types of transmission line´s resistance and inductance is undertook based on the model mentioned above and Finite Element Technique (FET).The result indicates that the unit resistance is increasing significantly when injected 400+HZ current. Similarly, the other type of ASCR has the same performance; however, the resistance of conductor with more layers is changing rapidly than the other conductors. All types of the ASCR have their inductance decreasing at the initial stage, then increase at certain point. By defined theory analysis, this paper proposed an intermediate frequency (1600 HZ) ice-melting method, the increase of the unit resistance and the choice of frequency is within the ideal extent. The proposed ice-melting method appears promising, and it needs further experimental practice.