Insulators' pollution problem: Experience from the coastal transmission system of Crete

摘要

Pollution of insulators is one of the most significant problems that can affect the reliability of power systems. Several practices have been employed to improve the insulation performance under polluted conditions such as extending the creepage distance, using specially designed profiles, washing of insulators and using hydrophobic materials to manufacture insulators or to coat their surfaces. Depending on the pollution type and severity as well as the local climatic conditions at the site of installation, different maintenance procedures against pollution should be employed. In this study, the insulators' pollution problem in the transmission system of Crete is described based on a statistical analysis of the insulators' faults since 1969. Also, the practices employed against insulators' pollution as well as their effectiveness are presented. Among them, the most efficient practice has been evinced the use of polymeric coatings and composite insulators. However, after about 2 decades of their large scale installation, without any faults, their performance becomes questionable due to the ageing of the polymeric materials. In order to prevent the risk of the in-service insulators failures, a fruitful collaboration of power network operator with local academia and research institutes has led to the investigation of new diagnostic procedures aiming at the assessment of the condition of field-aged insulators. To this end, the use of laser-induced breakdown spectroscopy (LIBS) technique is proposed for the remote and real-time diagnosis of the condition of in-service composite insulators.