Aging effect on leakage current flow in wooden poles

Insulation degradation leading to leakage current flow through high voltage insulators could result in catastrophic failures such as pole fires and damages to nearby equipment. This paper examines the leakage current distribution originating from the high voltage conductor to various locations through the wooden pole of various age profiles. The specimens that are investigated in this paper range from a new sample to an aged pole sample of more than 20 years in service. The main results show that the aging effect on the wooden pole has great effect on the wood resistance. The decaying of the wood reduces the wood resistance and thus increases the leakage current. Thermal images showing heating of the king bolt due to leakage currents are also presented.