Assessing the dynamic rating of overhead transmission lines Mohamed M. Saied * ,y Electrical Engineering Department, College of Engineering and Petroleum, Kuwait University, P.O. Box 5969, 13060 Kuwait SUMMARY This paper addresses the achievable advantage of the dynamic rating of overhead power lines based on the continuous monitoring of the ambient temperature and wind speed. Starting from their measured profiles on a typical summer day, the corresponding possible current loading of the line could be determined over the 24 hours. It is then compared with the conventional line rating calculated using the maximum daily temperature and the typically assumed value of 0.6 m/s for the wind speed. The additional daily transmitted energy resulting from the dynamic line rating (DLR) could be found. The procedure is applied to lines of different conductor radii. Results indicate an achievable increase in the daily transmitted energy of about 40%. Copyright # 2007 John Wiley & Sons, Ltd. key words: power transmission lines; conductors; heating; limiting; temperature; wind; monitoring 1. INTRODUCTION As a result of deregulating the power industry, the utilities are continuously exploring the available possibilities to run their activities in the most economical way. This includes, among other measures, the proper selection and/or design of new equipment, improving the utilization of already existing resources such as the application of line compensation, the forced cooling of equipment, and FACTS devices, as well as the cost effective operation of their systems without compromising either the supply reliability or its quality. This is valid for all activities pertinent to the generation, transmission, distribution, and the supply eventually committed for export to other utilities. Focusing on the transmission facilities, Reference [1] gives detailed guidelines for the proper rating of the underground and overhead transmission lines, and transmission system substations taking into account the compliance with the corresponding standards. Useful tables are given addressing the line conductor ampacity criteria, such as the relevant weather conditions (e.g., the ambient air temperature, wind speed, and solar insolation), maximum continuous conductor operating temperatures, and the conductor properties. EUROPEAN TRANSACTIONS ON ELECTRICAL POWER Euro. Trans. Electr. Power (in press) Published online in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/etep.151 *Correspondence to: Mohamed M. Saied, Electrical Engineering Department, College of Engineering and Petroleum, Kuwait University, P.O. Box 5969, 13060 Kuwait. y E-mail: saied@eng.kuniv.edu.kw Copyright # 2007 John Wiley & Sons, Ltd.