ThermalRate™ System

How It Works

The ThermalRate™ Monitor is comprised of a Sensor and a Controller. The Sensor mimics how the line behaves under the given weather conditions. The Sensor consists of two parallel replicas of the line conductor. One is heated with a constant power and one is not heated. The replicas have the same material, diameter, and surface as the line conductor. They are each approximately one foot in length to eliminate temperature fringe effects on the ends, and they are separated so that they do not affect each other's temperature. The Sensor is located near the line and oriented in the same direction as the line in order to experience the same weather conditions as the line itself. The Sensor has no direct contact with the line.

The temperature of the heated replica rises above that of the other replica. The weather conditions influence the difference in temperature between the two conductor replicas. By simply comparing the temperatures of two replicas and using IEEE-738 standard equations, the line capacity can be calculated and supplied to the power system operator. In summary, by measuring the two replica temperatures and the power into the heated replica, the effect of all weather conditions can be determined. This is a very direct approach for accurately calculating the line's thermal rating.