Reliability assessment of transformer insulating oil using accelerated life testing

Area of Science:

• Electrical Engineering
• Materials Science
• Reliability Engineering

Background:

• Transformer oil degradation impacts operational reliability and maintenance costs.
• Accurate lifetime prediction is challenging due to variable environmental and operating conditions.
• Existing methods may not adequately address the complexities of transformer oil aging.

Purpose of the Study:

• To develop a reliable method for predicting transformer oil lifetime under normal operating conditions.
• To reduce maintenance costs and improve transformer operational efficiency.
• To establish a robust framework for assessing transformer insulating oil reliability.

Main Methods:

• Utilized the theory of accelerated life testing (ALT).
• Developed an inverse power Weibull distribution model incorporating voltage.
• Presented a numerical procedure for parameter estimation and derived reliability indices.

Main Results:

• Validated the proposed method using real-world transformer oil lifetime data.
• Successfully predicted the reliability of transformer insulating oil under normal usage.
• Evaluated point and interval estimations for key reliability indices.

Conclusions:

• The proposed ALT-based method provides accurate lifetime predictions for transformer oil.
• Both reliable lifetime and mean lifetime are critical considerations for maintenance decisions.
• Simultaneous evaluation of these indices ensures optimal repair or replacement strategies for transformer oil.