Data-Driven Condition Assessment and Remaining Life Prediction of Low-Voltage Distribution Transformers Using Insulation Resistance Measurements: A Case Study of Ajayi Crowther University Distribution Network
No Thumbnail Available
Date
2026-06-01
Journal Title
Journal ISSN
Volume Title
Publisher
IRE JOURNALS
Abstract
This paper presents a comprehensive insulation
resistance (IR) assessment of low voltage distribution
transformers at Ajayi Crowther University (ACU), Oyo,
Nigeria. The study evaluates the safety, reliability, and
operational efficiency of four distribution transformers
(three 500 kVA units and one 750 kVA unit) through
systematic IR testing using a Megger MIT1025 insulation
tester. Testing was conducted in three configurations:
Line-to-Earth (L-E), Neutral-to-Earth (N-E), and Line-
to-Neutral (L-N), with results corrected to a standard
temperature of 20°C and benchmarked against IEEE
standards. Statistical analysis revealed an overall mean
corrected IR of 137.5 MΩ with a standard deviation of
21.46 MΩ. Three transformers (T1, T3, and T4)
demonstrated healthy insulation with corrected IR values
ranging from 100 to 160 MΩ. However, transformer T2
exhibited localized insulation degradation, failing the L-N
test with a corrected IR of 90 MΩ, below the IEEE
minimum threshold of 100 MΩ. The findings indicate that
while the university's electrical distribution system is
largely in satisfactory condition, immediate corrective
maintenance is required for T2.
Description
Keywords
Insulation Resistance, Distribution Transformers, Megger Testing, IEEE Standards, Preventive Maintenance, Power Quality, Electrical Safety.
Citation
APA