Development of an Integrated Monitoring System for Conductor Temperature and Sag in Power Transmission Line

The temperature sag of transmission line conductors is a key indicator in the design and operation of power transmission lines. Excessive sag not only poses safety hazards but also limits the transmission capacity of the lines. Due to the increasing demand for electricity consumption, many existing transmission lines have increased the maximum allowable operating temperature of the conductors from $70^{\circ}\mathrm{C}$ to $80^{\circ}\mathrm{C}$ to enhance their transmission capacity. This necessitates the verification or real-time monitoring of sag to ensure the safety of line operation and the equipment being crossed. This paper focuses on the measurement of conductor temperature and sag, and develops an integrated monitoring system for the temperature sag of transmission line conductors. From the development of monitoring terminals to the design of data links, and then to the construction of the overall system, it achieves real-time monitoring of the sag and temperature of overhead lines.

I. Introduction

Power transmission lines are an essential component in the construction of the smart grid transmission link, characterized by extensive geographical distribution, long distances, complex operating conditions, heavy inspection and maintenance workload, and susceptibility to natural environmental influences and external forces. Currently, the State Grid Corporation has accumulated a total length of transmission lines of 110 kV and above reaching over one million kilometers, and maintains an annual equipment scale growth rate of about 5%.