Replacement Strategy of Insulators Established by Probability of Failure

Abstract

Insulators comprise only 5% of the capital cost of transmission lines; they are accountable for 70% of line interruptions and 50% of maintenance costs of transmission lines. Major transmission lines situated in different parts of the world were mostly all constructed 30 years ago. These lines have either completed or are approaching the active life at 30 years. It is not possible to replace all insulators at a time in any utility. From a standpoint of consistency, it is quite important to locate insulators that require replacement prior to the occurrence of failure. Recalling these issues, a replacement strategy was modeled on insulator samples, operated at 154 kV, mechanical and electrical rating (M+E) 25,000 lbs and within the 10–50 years (Y) age group, collected in bulk for laboratory evaluation, based on the probability of mechanical failure (P(F)) of insulators. For conducting these studies, tensile load test such as combined electrical and mechanical failing load test was performed on selected 30 new and aged porcelain insulator samples from bulk to access recent condition. It was observed that insulators under service for 50 years manifested a decrease of 89.3% in quality factor (K), as compared to insulators within 10 years of service. A micro-structural study was carried out by using an optical microscope (OM) and a scanning electron microscope (SEM) for the further confirmation of previous evaluations. P(F) was derived by implementing Weibull distribution on the experimental observations. It was observed that insulators with an age of 50 years depicted a 2.7% increase in P(F), as compared to insulators with an age of 10 years. This article discussed a strategy for accessing the recent condition of new, aged bulk samples and the criteria of the replacement of the insulator string based on P(F).

Key technology of replacing insulators for 500kV transmission line with electric operation

“…(2) Apply for deactivation of the reclosing gate with the dispatching department, and formulate safety and technical measures by specialized workers and relevant personnel. (3) Explaining the work task, explaining the safety measures, analyzing the danger points and formulating protective measures [6] . The purpose of the preparation stage is to let all the staff understand the working environment, improve the safety awareness of the operators and confirm that they are clear about the dangerous points in the work, and rationally divide the work to improve the efficiency of the operation.…”

Superhydrophobic Surface on Insulators by Using Perfluoropolyether-Functionalized Silica Nanostructures for Preventing Stress Corrosion Cracking at the Pin–Cement Junction

“…where I corr -corrosion current density (μA/cm 2 ), Ew-corroded metal (g), and δ-density of metal (g/cm 3 ). The XPS analysis shows evidence of coating deterioration for T1.…”

“…The porcelain insulators offer excellent deterioration resistance, electrical strength, and temperature resistance. However, under the influence of highly corrosive environments and elevated temperatures in the coastal regions/coastal regions situated near industries, ceramic insulators suffer from corrosion. − …”

Dependence of mechanical properties of electroporcelain on quartz particle size subjected to cyclic tests

“…The estimated remaining lifetime of installed insulators has been always studied, but in the last few years, more and more researchers have been studying this question, mostly in close collaboration with operating energy companies. Especially the KEPCO Research Institute and Sungkyunkwan University in South Korea have been actively publishing studies on different insulator aging mechanisms since 2019 [1][2][3]. Insulator aging and replacement strategies have as well been studied by an IEEE working group [4].…”