Abstract: A high voltage (station class) surge arrester comprises a plurality of serially connected stage. Each stage comprises a plurality of low voltage (distribution class) polymer housed solid state surge arresters which are electrically matched. The individual surge arresters of each stage are connected together and to the respective surge arresters of the (or each) adjacent stage by means of cast metal mounting brackets (spiders) having plural equiangularly-spaced limbs to the ends of which the surge arresters are attached. Corona suppression rings are mounted at the top end of the arrester and separate corona suppression components are mounted at the ends of the limbs of the intermediate stages.

Abstract: An electrical surge arrester is manufactured by securing a stack of metal oxide varistor blocks between end terminations by passing a rod through through-holes in the varistor blocks and securing the ends of the rod to the end terminations. The through-holes are larger than the rod cross-section and a silicone rubber material is injected into the void which otherwise would exist between the rod and the interior surfaces of the through-holes in the varistor blocks. The silicone rubber material is also moulded around the exterior of the stacked varistor blocks and forms a shedded external housing for the arrester. The silicone rubber coatings on the varistor block internal and external surfaces effects a passivation function and means that the passivation coatings normally provided on the surfaces of varistor blocks by their manufacturers at significant cost can be omitted.