Incorporating Multi-Year Asset Replacement Time Into Calculation of Asset's Expected Annual Unavailability Due to End-of-Life Failure

• Published in: IEEE transactions on power systems Vol. 36; no. 6; pp. 5164 - 5174
• Main Authors: Kandic, Miodrag, Fernando, Ioni, Gole, Aniruddha, Wang, Liqun
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.11.2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Aging; aging failure; Asset management; Availability; Bipole (BP); Conditional PDF; Converters; Cost benefit analysis; Cumulative Distribution Function (CDF); Economic analysis; Economic impact; End of life; End-of-Life (EOL); EOL failure; Evaluation; HVdc; HVDC transmission; LCC (Line Commutated Converter); Lead time; Mathematical analysis; Mathematical model; Monte Carlo simulation; Pole; Probabilistic logic; Probability; Probability density function; Probability Density Function (PDF); repairable failure; Risk assessment; Valve Groups (VGs)
• ISSN: 0885-8950; 1558-0679
• DOI: 10.1109/TPWRS.2021.3072341

Aging asset management requires careful consideration of end-of-life of any asset. This is particularly serious with aging infrastructure which may require complete replacement of a large asset which has a long lead time. In many current End-of-Life analysis approaches to calculate unavailability, the period of interest is sub-divided into yearly cycles with the assumption that the asset is available at the start of the year. Although this assumption is adequate if the replacement time for the asset occurs within the year, with longer lead times this can create excessively optimistic availabilities. This paper presents an improved probabilistic tool for risk assessment due to End-of-Life failure unavailability which overcomes this deficiency. The End-of-Life methodology proposed in this paper is required when aging assets have long lead times to replacement and so the capital investment decision must be made several years ahead. The method is applied to evaluate the End-of-Life unavailability of Manitoba Hydro Bipole II HVdc converters. The results are corroborated using Monte Carlo simulation. Finally, the risk of End-of-Life is incorporated into an economic cost-benefit analysis corresponding to the presented unavailability evaluation method.