Analyzing Distribution Transformer Degradation with Increased Power Electronic Loads

TL;DR

This paper investigates how increasing power electronic loads and photovoltaic penetration affect distribution transformer degradation, highlighting the role of harmonics in transformer performance and proposing analysis methods using harmonic analysis in PSCAD/EMTdc.

Contribution

It provides a detailed harmonic analysis of distribution transformers under various load and PV scenarios, revealing conditions that worsen or improve transformer degradation.

Findings

High power electronic loads increase harmonic content and transformer losses.

Increasing PV can reduce harmonics and improve transformer performance.

Harmonic effects depend on load composition and PV penetration levels.

Abstract

The influx of non-linear power electronic loads into the distribution network has the potential to disrupt the existing distribution transformer operations. They were not designed to mediate the excessive heating losses generated from the harmonics. To have a good understanding of current standing challenges, a knowledge of the generation and load mix as well as the current harmonic estimations are essential for designing transformers and evaluating their performance. In this paper, we investigate a mixture of essential power electronic loads for a household designed in PSCAD/EMTdc and their potential impacts on transformer eddy current losses and derating using harmonic analysis. The various scenarios have been studied with increasing PV penetrations. The peak load conditions are chosen for each scenario to perform a transformer derating analysis. Our findings reveal that in the presence of high power electronic loads (especially third harmonics), along with increasing PV generation may worsen transformer degradation. However, with a low amount of power electronic loads, additional PV generation helps to reduce the harmonic content in the current and improve transformer performance.