Analysis of the neutral current for two-step-type poles in distribution lines

One-step-type poles and two-step-type poles are used in KEPCO's distribution system. An unbalanced current may flow through the neutral wire in three-phase four-wire distribution systems due to unbalanced loads. Generally, the power line and the communication line are installed in close proximity due to the topography of Korea. By means of electrostatic induction, electromagnetic induction, and harmonic induction, the power line induces damaging voltage and current in the communication line. This paper calculates the neutral current in KEPCO's distribution system by using the Electromagnetic Transients Program (EMTP) by composing various simulated conditions, and the results are verified by vector analysis. Index Terms--Electromagnetic Transients Program (EMTP), KEPCO's distribution system, neutral current, one-step-type pole, two-step-type pole.