Document Type

Article

Publication Date

2009

Journal or Book Title

Annals of Applied Statistics

Volume

3

Issue

2

First Page

857

Last Page

879

DOI

10.1214/00-AOAS231

Abstract

Prediction of the remaining life of high-voltage power transformers is an important issue for energy companies because of the need for planning maintenance and capital expenditures. Lifetime data for such transformers are complicated because transformer lifetimes can extend over many decades and transformer designs and manufacturing practices have evolved. We were asked to develop statistically-based predictions for the lifetimes of an energy company’s fleet of high-voltage transmission and distribution transformers. The company’s data records begin in 1980, providing information on installation and failure dates of transformers. Although the dataset contains many units that were installed before 1980, there is no information about units that were installed and failed before 1980. Thus, the data are left truncated and right censored. We use a parametric lifetime model to describe the lifetime distribution of individual transformers. We develop a statistical procedure, based on age-adjusted life distributions, for computing a prediction interval for remaining life for individual transformers now in service. We then extend these ideas to provide predictions and prediction intervals for the cumulative number of failures, over a range of time, for the overall fleet of transformers.

Comments

This article is from Annals of Applied Statistics 3, no. 2 (2009): 857–879, doi:10.1214/00-AOAS231.

Copyright Owner

Institute of Mathematical Statistics

Language

en

File Format

application/pdf

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