Sag-tension calculation program for wood pole overhead lines

This paper presents studies into a new program used to calculate sag and tension of conductors on wood pole lines considering all relevant parameters, such as conductor temperature, wind and ice loadings and creep. Based on this information and data provided by the user, the program also provides information on clearances and structural loadings. Furthermore, the paper describes expressions used to develop the program. The program is in a Microsoft Excel domain for ease of use by SSE planners for whom the program has been developed and is found to provide more information than readily available programs on the market. A set of data is obtained experimentally at the Scottish and Southern Energy (SSE) overhead line training school using a 58 metre span of 50 millimetre Hazel conductor (all aluminium alloy conductor) strung at various tensions between two wood poles at an air temperature of 2.5 degrees Celsius. This data is used to validate the data from the new program. Attentive analysis of results shows a close correlation between the two methods.