Reliable Power Transformer Efficiency Tests

Abstract

Power transformer efficiency measurements are a crucial part of the acceptance tests of a power transformer. These tests have increased importance since the EU Ecodesign Directive per 1 July 2015 has put efficiency limits to power transformers that are sold on the European market. In this paper we present a series of measures to assure that power transformer efficiency tests performed by power transformer manufacturers are accurate and reliable. This includes the development of more accurate industrial loss measurement systems (LMS), optimized LMS calibration approaches, and a reference system for on-site LMS calibration.