Performance of distribution-class surge arresters under dry and artificial pollution conditions

This paper presents an experimental investigation of distribution-class surge arrester (SA) performance under dry, clean-fog and salt-fog conditions. Two SA rated 11 kV and three SA rated 33 kV were tested inside a salt-fog chamber to investigate how the internal active material (either zinc oxide/metal oxide "ZnO" or silicon carbide "SiC") and the arrester housing material affect the overall performance under different pollution severities. Tests were conducted on SiC porcelain-, ZnO polymeric- and ZnO silicone rubber- (SiR) housed SA. Both the internal and the external currents were measured for each SA up to its maximum continuous operating voltage (MCOV). Results reveal that new ZnO SiR-housed SA shows its superior performance under salt-fog condition over the other two types tested. On the other hand, aged ZnO SiR-housed SA can have high external current close to that of SiC porcelain-housed SA. New ZnO polymeric-housed SA gives the highest rms external and internal currents under salt-fog condition as its housing material is hydrophobic in nature and has the shortest creepage distance.