Impact of Common Defects in Silicone Composite Long Rod Insulators on Radio Frequency Interference Spectra

Composite insulators employed in HVAC or HVDC transmission lines experience common defects, viz. rodent / bird pecking damage, damage due to flashover and formation of fungi and algae growth on the shed. Disturbance due to radio frequency interference from transmission lines is a major design consideration for transmission line. Though each and every equipment of transmission line is commissioned in system after stringent testing, radio frequency interference from transmission line to nearby electrical equipment is inevitable in many occasions. This paper aims in presenting the impact of commonly occurring in-service defects in composite insulator on radio frequency interference spectra. RFI is recorded by emulating those common defects in actual sample with normal operating voltage. A 245 kV, 160 kN silicone composite long rod insulator was chosen for this purpose and experiments were performed with normal operating voltage of 245 kV transmission line.