Harmonics propagation can be studied by various harmonics load flow methods. The propagation of balanced triplen harmonics currents produced by synchronous generator through medium voltage underground cable of distribution network can be modeled by triplen harmonics voltages acting as the source for zero sequence network. Third harmonics current being a major component of triplen harmonics is being studied for various underground cable parameters, generator and transformer grounding methods, load variation/connection and distributed generation configuration. Time domain analysis is used for simulation and the model is validated with the third harmonics current measurement at site. Third harmonics current propagation is influenced by third harmonics voltage source, cable length, generator grounding, number of parallel cables, cable size, load, load connection and DG configuration. © 2011 IEEE.