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.
Replica of ThermalRate™ Conductor
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.