Real-time monitoring allows the determination of the line state and the calculation of the actual rating value. The real-time monitoring systems measure sag, conductor tension, conductor temperature, or weather-related magnitudes. In this paper, a new ampacity monitoring system for overhead lines, based on the conductor tension, the ambient temperature, the solar radiation, and the current intensity is presented. The measurements are transmitted via general-packet radio service to a control center where a software program calculates the ampacity value. The system takes the creep deformation experienced by the conductors during their lifetime into account and calibrates the tension-temperature reference and the maximum-allowable temperature in order to obtain the ampacity. The system includes hardware implementation and remote-control software.

At the present time, there is great pressure to increase the power flow in existing right of ways using existing infrastructure as far as possible. In this paper, the diverse options for increasing the rating of overhead lines are presented and analyzed. By means of a comparative study, their advantages and drawbacks are highlighted. In addition, the factors that determine the choice of the method are analyzed.

Commercially available sag-tension programs give good results for most practical applications. However, they have some limitations concerning gap-type conductors. A separate aluminum and core creep calculation is needed due to the special structure of gap-type conductors. For the same reason, different core and aluminum lengths have to be considered. In order to take the creep during the installation process into account, flexibility for the consideration of several stages is needed. A method that considers all of these characteristics has been developed and implemented in a comprehensive, versatile, and flexible sag-tension software tool, called Strain Tension in Overhead Conductors. The program has been designed for the analysis of gap-type conductors. However, the method is a general method that can be used for any type of conductor, especially when flexibility for the calculation of several creep conditions is needed.

Many real-time overhead line ampacity monitoring systems are based on the calculation of wind speed. The wind speed is obtained from the conductor temperature. The conductor temperature can be measured directly or it can be obtained indirectly from other magnitudes such as the tension or the sag. An error in the temperature difference gives as a result an error in the calculated wind speed and ampacity values. This study analyses and quantifies the influence of the temperature difference error in the obtained ampacity value. As a result, a method for the evaluation and the correction of the ampacity error that can be used in the monitoring systems is proposed.

Reconductoring with high-temperature low-sag (HTLS) conductors is an alternative to the traditional uprating methods. An increase in the obtained rating depends on the mechanical and thermal behaviours of the conductor. The HTLS conductors are presented and mechanical calculation methods are analysed taking into account the special characteristics of these conductors. The widely used graphical method and the recently developed STOC method have been analysed.