Detection of Critical Conditions in Ceramic Insulators Based on Harmonic Analysis of Leakage Current

Abstract

This article presents an online diagnostics method to predict critical conditions in ceramic insulators. For this purpose, a variety of experimental tests have been conducted on different kinds of ceramic insulators under different environmental conditions in order to analyze their leakage current. Fast Fourier transform analysis of leakage currents shows a strong correlation between the ratio of the third to fifth harmonic amplitude regarding occurrence of critical conditions and degree of insulator ageing. Therefore, the index of the third to fifth harmonic amplitude is utilized as the detection indicator of critical conditions in ceramic insulators. An increase in the index of the third to fifth harmonic amplitude to more than one represents a critical condition in the insulators and estimates a high probability of flashover occurrence. The obtained results have also shown the viability of the index in insulators monitoring procedures. Training the proposed index to a microprocessor powered device gives ability to the system for online diagnosis of ceramic insulator qualifications, detecting critical conditions, and predicting flashover occurrence.

Keywords:

• leakage current
• harmonic analysis
• critical condition
• ceramice insulators

Additional information

Notes on contributors

Mousalreza Faramarzi Palangar

Mousalreza Faramarzi Palangar was born in Mashhad, Iran, in 1989. He received his B.Sc. in electrical engineering from Urmia University, Urmia, Iran, and his M.Sc. in electrical power engineering and area of high-voltage engineering from the Babol University of Technology, Babol, Iran, in 2015. His research interests include condition monitoring of high-voltage equipment, insulation performance, design and control detection system for protection of power system components, and wireless power transfer.

Mohammad Mirzaie

Mohammad Mirzaie was born in Ghaem Shahr, Iran, in 1975. He obtained his B.Sc. and M.Sc. in electrical engineering from University of Shahid Chamran, Ahvaz, Iran, and Iran University of Science and Technology, Tehran, Iran, in 1997 and 2000, respectively, and his Ph.D. in electrical engineering from the Iran University of Science and Technology in 2007. He worked as an assistant professor in the Electrical and Computer Engineering Faculty of Babol University of Technology since 2007. His research interests include life management of high-voltage equipment; high-voltage engineering; intelligence networks for internal faults assessment in equipment; and studying insulation systems in transformers, cables, generators, breakers, insulators, electrical motors, and overhead transmission lines.