Nowadays, there are a lot of electronic devices are used in industrials, offices, and residential homes. The reasons include these devices work around the clock with great precision and accuracy, with the help of automations and systems. However, this alarming development causes serious concern over power system safety and reliability. These devices are also known as nonlinear loads, and during operation they inject pulses into the power system. This causes distortions in the initially pure sinusoidal waveforms, and produces harmonics in current. The higher harmonic contents in current, which is quantified as percentage of Total Harmonic Distortion in current (% THDi), the worse impact to the power cable operation. The insulation of power cable may fail, thus results in catastrophic malfunction of power distribution system. This thesis looked into power cable sizing by taking harmonics in current into account. As the value of current RMS increases due to harmonics, the power cable size needs to be calculated to sustain the additional losses. This thesis looked into producing a method to select power cable size under nonlinear load operation. To simplify the analysis, this thesis considers a balanced, 400V three phase four wire system by MATLAB modelling. The load attached to the system is of nonlinear in nature, and the impact of %THDi to the RMS value of current produces the power cable sizing method. To be more reflective to actual site condition, Politeknik Seberang Prai was chosen as site for data logging. The finding of this thesis includes the method of selecting power cable size with harmonics in current. Result shows that the greater %THDi, more losses occurs at the cables. A mathematical expression created as a sizing equation with the inclusion of %THDi. The finding is important for design of power distribution system planning and management in anticipating the effect of electronic devices to the system.
