Overhead lines - Sizing

This article sets out the rules for geometric, electrical and mechanical dimensioning of overhead lines.

Despite advances in meteorological studies and statistics, taking the climatic environment into account is still a major concern for line builders. In view of the many uses to which electricity is put today, which are often incompatible with long interruptions to the power supply, lines have to be able to provide power in the most severe weather conditions. In this field, construction guidelines have been the subject of numerous studies and form a coherent whole, confirmed by experience feedback: by choosing the degree of severity of climatic conditions (wind zone, frost overload, etc.), the project manager in fact defines the most appropriate dimensioning of the structure and can justify the cost.

Another more recent concern is quality of service. It is possible to reduce the number of fugitive lightning faults affecting HV lines. These faults are known to cause major disruption to industrial users.

The rules set out in this booklet are those used in France. They are not directly applicable in foreign countries, due to different climatic conditions on the one hand, and to the diversity of administrative regulations and standards on the other. However, the reader will find all the explanations on dimensioning rules, calculation methods and choices in the booklet, which will be useful when drawing up a line project in a foreign country.

The "Overhead lines" article is the subject of several fascicles:

D 4420 Line presentation and calculation

D 4421 Dimensioning

D 4422 Overhead line equipment

D 4429 Construction

D 4430 Maintenance

The subjects are not independent of each other. Readers will often need to refer to other issues.

This article is an update of the text written by Yves PORCHERON and published in 1992 in this treatise. Part of the text has been retained.