Abstract
Transformers are equipment designed to operate perfectly at linear loads. Nowadays with wide use of modern technology requirement and industry needs which utilize nonlinear loads, the transformers are subjected to more nonlinear loads. Many research studied the influence of harmonics upon transformers. This paper focuses on transformer losses calculations for the case study of Mubarak Pumping Station (MPS) with and without passive harmonic filters. Also harmonic indices including K-Factor transformer, Total Harmonic Distortion (THD), Harmonic Loss Factor (FHL) and de-rating of transformer are calculated. When distribution transformer is operating under harmonic load, the value of load losses is increased, while the no load losses increased with a little amount. No load losses of a distribution transformer under harmonic loads can increase its operating cost. K-Factor calculation depends upon the fundamental current and the harmonic current components, and it is an indicative value of the harmonic contents in the power system.