Power TranformersS Diagnosis: Status Evaluation

Abstract

The reliability of the electrical grid depends on the
availability and performance of crucial components such as
power transformers. A failure in these expensive devices
threatens supply energy warranty and system overhaul
reliability. As transformers approach their end of life, the
failure rate tends to increase and, therefore, both equipment
diagnostics and working condition assessment are important
to detect oncoming faults.
In this work, we develop a state assessment methodology,
able to evaluate power transformers health conditions. The
study is about the transformer operation analysis and the
associated status index calculation. This index value classifies
the transformer general operation, according to the
information of five partial indexes, reflecting the work
conditions of most critical equipment: insulating oil and
paper, winding and bushings. This contribution also presents
an extensive transformer state analysis, backed up by in-service equipment.