Design of Utility Harmonic Mitigation Filters for Power Transformers

Abstract

Power transformers are the most expensive assets for power utilities. They are exposed to harmonic distortion causes negative effects on their operation. Traditionally, harmonic mitigation filters were installed by large power users on the customer side of the power system and the utilities had no control over their operation. Utilities should invest in harmonic mitigation filters to grant them full controllability on the harmonic content coming from either side (utility/customer). This paper presents a proposed design of harmonic mitigation filters installed by the power utilities for power transformers. DIgSILENT software is used for the modelling, analysis, and implementation of the proposed filter design and the verification case studies. A comparative study shows the significant reduction of the total harmonic distortion (THD) for power transformers using the designed filters. With this THD reduction, the negative impacts are reduced and the designed life expectancy of the transformers would be increased.