Development of a Method of Calculating the Melting Characteristics of OPGW Strands Due to DC Arc Simulating Lightning Strike

Abstract

Some strands of composite fiber-optic ground wire (OPGW) are sometimes melted and broken by high-energy lightning strikes. DC arc tests simulating lightning strikes have been performed to obtain the melting and breaking characteristics of OPGW strands. The tests have to be performed under many conditions concerning the arc (e.g., current, duration, polarity, gap length) and the OPGW (e.g., size, type, and number of strands) to clarify the melting and breaking characteristics of the strands. In this paper, the calculations regarding the melting characteristics of strands are performed considering the transferred heat and its area from the arc to the strands under the aforementioned conditions. The melting characteristics of strands are calculated with an arc current of 1-100 kA considering the measured current of actual lightning. The calculation results of the strand melting duration depending on arc current show good agreement with the experimental values obtained in dc arc tests.

Melting and breaking characteristics of strands of high‐strength and high‐corrosion‐resistant OPGW due to DC arc discharge simulating high‐energy lightning strike

“…That is, when compared at equal electric charge, are more likely to break at lower current; this agrees with experimental trends in the reference 5 . Similar calculation results presented in the reference 14 are explained by the fact that arc area is narrower with lower current, and strands are likely to break in a relatively short time.…”

“…In order to discuss the test results, the number of broken strands was calculated using a program developed by CRIEPI 14 . Details of the calculation method are given in the reference; 14 an overview is given below.…”

Calculation of OPGW Strands Melting due to DC Arc Discharge Simulating High-Energy Lightning Strike

“…Calculations were carried out using the method developed in [7]. This chapter summarizes the calculation methods and conditions.…”

“…For example, as shown in Figure 1, the measured current was not a pulse current but similar to a direct current (DC) with a square wave shape [1]. Therefore, in order to clarify the melting and breaking characteristics of conventional and newly-developed OPGW strands, DC arc tests have been performed and the test conditions that adequately simulate high-energy lightning strikes have also been investigated [2][3][4][5][6], and the authors have developed a method of calculating the strands melting due to DC arcs [7].…”

Experimental analysis of the strands breaking characteristics of optical fibre composite overhead ground wire due to simulating lightning strike

“…In order to obtain the fusing characteristics of OPGW, a DC arc test that simulated lightning strikes were performed with different conditions of arc (current, duration, polarity, gap length) and OPGW (size, type and number of strands) to study the melting and fracture characteristics of OPGW. Iwata et al [16][17][18] calculated the strands breaking duration depending on the arc current. The calculation results showed good agreement with the tendency of the experimental results and the conclusion was that breaking time was inversely proportional to the current.…”