Preventing Transmission Line damage caused by ice with smart on-line conductor Monitoring

摘要

OTLM (Overhead Transmission Line Monitoring) is a system solution for monitoring and rating of existing and new overhead lines (OHL) based on real-time monitoring of conductor temperature, sag, load, and weather conditions in order to ensure save maximum utilization of transmission line ampacity. Successful development and more than 10 years' of experience in using the OTLM system on transmission networks in several countries all over the world has initiated some system upgrades to ensure even more crucial information on OHL behaviour. The existing functionality of conductor temperature measurements (used for static rating-STR) was initially combined with a weather station measurement that enables the determination of dynamic rating (DTR). With additional inclination (sag/tension) measurements, we developed the OTLM-SAG application. With this additional feature we are able to determine the sag on critical spans. This additional information is especially useful in case of OHL crossings over roads, railroads, other overhead lines, etc. Additionally, measured data like angle (sag) is implemented to the software application to detect ice overloads or fallen trees. The mathematical relationship between the conductor's tensile force and sag is crucial for the calculation of the conductor's expansion (tension) and final length over a constant span distance. The reliability of ice thickness calculations mainly depends on the accuracy of conductor temperature and angle/sag measurements. The OTLM-ICE application enables the operator of the transmission network to monitor sag and clearance changes on a conductor, subjected to ice overloads. The operator can optimize and determine the suitable ampacity of transmission lines in order to prevent the damage in early phases of ice-rain.