Evaluation of Aged High Voltage Ceramic Suspension Insulators – A Synthesized Analysis of In-Service Insulator Aging Assessments

Abstract

The conditional assessment of high voltage ceramic insulators is well understood to provide insight into the continued performance of a given population. The more commonality across the population (manufacturer, class, year produced, factory of origin, and even batch), the more we can infer from the analysis of a small sample. In contrast, this paper reviews the results of a large volume of assessments revealing generalities useful to asset managers, design engineers, and standards committees as inferences can be made regarding the expected long-term performance of the different insulating technologies and the risk of failure of these assets as they age.
The criticality of this information only increases as utilities face the dual challenge associated with electrification: working to meet increased demand while simultaneously managing millions of aging insulators, many requiring replacement in order to maintain the dependability and reliability of their network. Utilities contend with the decision making required to appropriately balance the construction of new lines while also increasing the reliability of existing lines through rehabilitation projects targeting underperforming insulator populations.
As it is well established that a decrease in performance can be expected with certain ceramic insulators (with porcelain and toughened glass inclusively defined as ceramic), our study focuses strictly on units returned from service. Collected from utilities around the world, our analysis is based on well over two-thousand individual samples across more than 60 separate populations. Our synthesis includes populations with years in service spanning from a handful of years to an impressive one-hundred years in service. It includes a multitude of manufacturers without prejudice as it does not delve into any individual-level performance but rather investigates the generalized performance attributes that can be applied more broadly to any in-service ceramic insulator population.

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