Prototypes of polymer-impregnated reforested wood crossarms subjected to partial discharge tests

Brazil´s vast territory and huge forested regions have contributed to the widespread use of traditional crossarms made of native wood species in distribution lines. However, this situation is changing due to the increasingly high cost of native species and Brazil´s environmental laws. In response to these changes, electric power suppliers have been seeking alternatives, and prototypes of reforested wood crossarms (such as Eucalyptus citriodora) impregnated with polymer (castor oil-based polyurethane resin) have been studied for application as mechanical supports for electrical power distribution systems, with very satisfactory results. This paper discusses mechanical and electrical tests conducted on this new material under critical conditions of temperature and relative air humidity. Also presented are the results of electrical tests conducted at Graz Technology University´s Institute of High Voltage Engineering and System Management in Austria to analyze the material´s insulation performance under electrical stress particularly under partial discharge during critical operating conditions