Flashover Performance of Composite and Porcelain Insulators

Insulators are required in a power system network to provide isolation for line conductors from ground and give necessary mechanical support. Different types of insulators are being used for transmission lines and in substations. Ceramic insulators, porcelain and glass insulators are in use for very long time. Non-ceramic insulators such as silicone rubber composite insulators are presently being used by many power utilities. Experiments were carried out on 220 kV composite and solid-core porcelain post insulator to understand the breakdown voltages under AC, lightning and switching impulse voltages. The results of the breakdown voltages of porcelain and silicone rubber composite insulator under AC, lighting impulse and switching impulse voltages are presented in this paper