Problems, Investigation Methods, and Solution of Using String Suspension Insulators in Transmission System

摘要

This paper presents the problems, investigation methods, and solution of using suspension string insulators in Thailand. Corona loss, punctured insulator and easy flashover for contaminated insulators are the problems that have existed after using these insulators for a period of time, usually after a few years. These problems incur the reliability degradation of electrical power system. The investigation methods includes; first examination of corona phenomena of the string insulators helps in separating any punctured insulators out of the tested string insulators by observing the corona spots. Second, distributed voltage of the string insulators was checked by using the simple small sphere gaps. Finally, the string insulator characteristics under high humidity were under investigation. We propose the alternating shed long rod insulator prototypes designed and constructed according to IEC to handle the aforementioned problems. The test results are reported in this paper.