Reduction in distribution transformer failure rates and nuisance outages using improved lightning protection concepts

Journal Article · Sat Apr 01 04:00:00 EST 1995 · IEEE Transactions on Power Delivery

DOI:https://doi.org/10.1109/61.400854· OSTI ID:64386

Plummer, C W ^[1]; Goedde, G L ^[2]; Pettit, Jr, E L ^[3]; Godbee, J S; Hennessey, M G ^[4]

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1. Cooper Power Systems, Pewaukee, WI (United States)
2. Cooper Power Systems, Franksville, WI (United States)
3. Pettit (Elmer L. Jr.), Daytona Beach, FL (United States)
4. Florida Power and Light, Daytona Beach, FL (United States)

This paper presents a case study of an overhead distribution feeder in a very high keraunic area. The feeder was experiencing approximately twice the number of lightning caused transformer failures per year than any other distribution feeder in the area. In an attempt to lower the outage rate and the repair costs, the lightning protection for this feeder was studied and a new protection system was installed. The first section of this paper discusses the outage history of this feeder and existing transformer overvoltage protection. It then details the steps that were taken to improve the protection so acceptable customer service could be achieved. The interruption data results for one year after the protection changes were implemented are then presented. The results from the field trial of the new lightning protection scheme exhibit a significant improvement in the feeder service reliability. The last section of this paper is a compilation of teardown data of failed distribution transformers. The analysis includes failed transformers from the study feeder, and failed transformers from the same utility, but not part of the feeder study. The causes of the transformer failures were tabulated. The results from the teardowns indicate that a high percentage of distribution transformers with interlaced and non-interlaced secondary windings fall from lowside voltage surges.

• OSTI ID: 64386
• Journal Information: IEEE Transactions on Power Delivery, Journal Name: IEEE Transactions on Power Delivery Journal Issue: 2 Vol. 10; ISSN ITPDE5; ISSN 0885-8977
• Country of Publication: United States
• Language: English

Related Subjects

24 POWER TRANSMISSION AND DISTRIBUTION
ELECTRICAL TRANSIENTS
LIGHTNING ARRESTERS
OVERVOLTAGE
POWER DISTRIBUTION SYSTEMS
SURGES
TRANSFORMERS