The Study of Third Harmonic Current Contribution During Three phase-to-ground Fault

Harmonic is defined as the voltage and current distortion in the waveform. It exists from the source such as synchronous generator and non-linear load. Third harmonic is the presence of voltage and current distortion expressed in terms of harmonics frequencies 150 Hz. During three phase-to-ground fault, the fundamental fault current share the same return path as third harmonic. Thus, the synchronous generator is used as the source of third harmonic in the lab experiment to investigate the characteristic of third harmonic and the amount of its contribution to the system during three phase-to-ground fault. In the experiment, the variables that are varied including the fault impedance (Zf), filter mode (by zig-zag transformer) and Neutral Earthing Resistor (NER). The load impedance sets are also changed to study how the load can affect the contribution of third harmonic current.