Perhitungan Dan Analisis Derating Trafo Daya Karena Pembebanan Non-Linier

Power transformers are commonly used in power plants or substations to step-up or step-down. The performance of a power transformer is infuenced by derating or a decrease in power capacity caused by harmonic distortion. In practice, harmonics are called power quality disturbances caused by non-linear loads so that derating occurs in the transformer. This research was carried out simulation of Total Harmonic Distortion (THD) using ETAP software with SMPS loading data non-linear power transformer 1 with a capacity of 60 MVA, and power transformer 2 with a capacity of 30 MVA Blora Substation 150 KV according to current harmonic standards regulated in IEEE 519 -2014. Calculation and analysis of derating power transformers due to non-linear loads using the CBEMA and K-Factor IEEE methods where the harmonic spectrum and rms currents, peak currents must first identified from the simulation results. The results showed indicated that at the stage of simulation, the result of the current THD were 9.26% for Transformer 1, and 9.04% for Transformer 2. So that the derating of the power transformer (new MVA) resulting from non-linear loading with the CBEMA method is 57 MVA and 28.5 MVA, and the IEEE K-factor method is 57.9 MVA and 28.8 MVA. From the two methods, the derating comparison that occurs in the Blora 150 KV substation power transformer is not much differen