Neutral to Earth Voltage Analysis in Harmonic Polluted Distribution Networks with Multi- Grounded Neutrals

Authors: G. Ahmadi, S.M. Shahrtash

Abstract:

A multiphase harmonic load flow algorithm is developed based on backward/forward sweep to examine the effects of various factors on the neutral to earth voltage (NEV), including unsymmetrical system configuration, load unbalance and harmonic injection. The proposed algorithm composes fundamental frequency and harmonic frequencies power flows. The algorithm and the associated models are tested on IEEE 13 bus system. The magnitude of NEV is investigated under various conditions of the number of grounding rods per feeder lengths, the grounding rods resistance and the grounding resistance of the in feeding source. Additionally, the harmonic injection of nonlinear loads has been considered and its influences on NEV under different conditions are shown.

Keywords: NEV, Distribution System, Multi-grounded, Backward/Forward Sweep, Harmonic Analysis

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1077926

References:

[1]. Jen-Hao Teng, Chuo-Yean Chang, "Backward/Forward Sweep-Based Harmonic Analysis Method for Distribution Systems", IEEE Transactions on Power Delivery, 2007, pp. 1665-1672.
[2]. Rade M. Ciric, Antonio Padilha Feltrin, Luis F. Ochoa, "Power Flow in Four-Wire Distribution NetworksÔÇöGeneral Approach", IEEE Transactions on Power System, 2003, pp.1283-1290.
[3]. Jian jiang, "Elevated Neutral to Earth Voltage in Distribution Systems Including Harmonics" A Dissertation Presented to the Graduate School of Clemson University, 2006.
[4]. "Radial Distribution Test Feeders", Distribution System Analysis Subcommittee Report, IEEE Power Engineering Society, 2001, pp.908- 912.
[5]. "Test Systems for Harmonics Modeling and Simulation", Task Force on Harmonics Modeling and Simulation, IEEE Transactions on Power Delivery, 1999, pp.579 - 587.
[6]. L. M. Wedepohl, H.V. Nguyen, G.D. Irwin, "Frequency- Dependent Transformation Matrices for Untransposed Transmission Lines using Newton-Raphson Method", IEEE Transactions on Power Systems, 1996, pp.1538-1546.
[7]. Jen-Hao Teng, "A Direct Approach for Distribution System Load Flow Solutions", IEEE Transactions on Power Delivery, 2003, pp.882-887.