# Distributed Optical Fiber Sensing of Temperature Rise During 110 kV Conductor–Ground Wire Ice-Shedding Discharge

## TL;DR

This paper introduces a new method using optical fiber sensors to detect ice-shedding discharges on power lines, which can help prevent line tripping.

## Contribution

The study proposes and validates a distributed optical fiber sensing approach for detecting ice-shedding discharge on high-voltage transmission lines.

## Key findings

- Ice-shedding discharge causes a localized temperature rise detectable by BFS changes in OPGW fibers.
- The BFS increment varies with icing conditions, being highest under no icing and lowest under glaze ice.
- A spatial resolution better than 0.1 m and a sampling rate of at least 5 Hz are needed for effective discharge detection.

## Abstract

Ice-shedding on overhead transmission lines can easily lead to jump discharge and subsequent line tripping, and effective monitoring methods are still lacking. To address this problem, this study proposes a distributed optical fiber sensing approach based on Brillouin optical time-domain reflectometry (BOTDR) for detecting ice-shedding discharge on 110 kV conductor–ground wire. The optical fibers embedded in an optical fiber composite overhead ground wire (OPGW) are used as sensing elements. Through simulated ice-shedding discharge experiments under different icing conditions, the Brillouin frequency shift (BFS) characteristics along the OPGW fiber are investigated, and the relationship between the BFS increment caused by the discharge-induced temperature rise and the discharge parameters is revealed. The experimental results show that ice-shedding discharge produces a localized temperature-rise region in the OPGW fiber, with an axial extent of 20–40 cm and a duration of 2–4 s. The maximum BFS increment due to the discharge temperature rise, ΔvTm, is strongly dependent on the icing condition. Under conditions of no icing, light rime, and glaze ice on the conductor only, ΔvTm remains within 5.43–7.94 MHz, whereas when both the conductor and ground wire are covered with glaze ice, ΔvTm decreases significantly to 2.91–3.76 MHz. Further analysis indicates that, to satisfy the requirements for detecting ice-shedding discharge, the BOTDR must achieve a spatial resolution better than 0.1 m and a temporal sampling rate of no less than 5 Hz. These findings verify the feasibility of using distributed optical fiber sensing technology to detect ice-shedding discharge and provide experimental support for studies on the associated discharge mechanisms.