Monitoring of Leakage Current for Composite Insulators and Electrical Devices

Electrical insulation is an important part of all electrical systems. The level of insulation safety provided by an insulator depends on the amount of leakage current flowing on its surface. Actually increased leakage current causes a part of high voltage to appear at dead end of insulator. This voltage may sometimes be of order of 1000 to 5000 Volts depending upon weather conditions. Such a level of leakage current causes hazards to public safety as well as losses. So to monitor and keep the leakage current low is an important parameter to be considered by designers and electric supply companies. This paper highlights the concepts and importance of leakage current for insulators and general electrical devices. In addition, different methods of measurements of leakage current are reviewed. Particular focus has been made on leakage current monitoring of composite insulators. Feasibility of these methods for some particular environments has also been discussed.