Use of wooden structures to reduce electric field under EHV transmission lines

The considerable high electric field underneath extra high voltage overhead lines could be minimised in a localized area by the shielding effect of a conductive wooden framework. Electrical resistivity of wood is the key factor to control the induced voltage on the wooden framework. Wood with lower resistivity has a higher capability to reduce the electric field inside the framework. The moisture content of the wood affects its resistivity. Measurement results of wood samples were given in this paper to show the change of moisture content and wood resistivity with the weather conditions in a long time span. Simulation in CDEGS was made to find out the effect of wood with different resistivities on the electric field under a HV overhead line. Simulation results were verified by the measurements carried out inside and around the wooden pergola in the site.