International Journal of Engineering and Information Systems (IJEAIS)   Year: 2020 | Volume: 4 | Issue: 12 | Page No.: 128-137 A study of Harmonic Control 33/11 kv Transformer of AL OMERA Substation SEDC network Elebaid Khalid Elsayed , Ahmed Mohammed Alsayed , Mohammed Ali AbulGasim , Hisham Hussein Bahar Aldein , Rahama Ibrahim Adam , Hashim Omer Hassan Musa Abstract: The Harmonics in Distribution Systems come from transformers or saturation reactors, arc furnace, welding machines, florescent lamps, rotating machines and power electronics devices. In general, the nonlinear loads in which the relationship between the voltage and current is not constant. A case study of (SEDC) network (AL OMERA Substation) was investigated using Network Analyzer (AR5) for the reading, and ETAP simulation program. The results of harmonic analysis were compared with IEEE519-1992 limits (5% VTHD). It was found that the total harmonic distortion limit for current in the simulated case study network exceeded the limits (8.9 %VTHD). Hence harmonic mitigation solution chosen was the passive filter.