Characteristics Analysis of Voltage Sag and Voltage Swell in Multi-Grounded Four-Wire Power Distribution Systems

In North America, Most power distribution systems employ a four-wire multi-grounded neutral (MGN) design. This paper has explained the inherent characteristics of multi-grounded three-phase four-wire distribution systems under unbalanced situations. As a result, the mechanism of voltage swell and voltage sag in MGN feeders becomes difficult to understand. The simulation tool that has been used in this paper is MATLAB under Windows software. In this paper the equivalent model of a full-scale multigrounded distribution system implemented by MATLAB is introduced. The results are expected to help utility engineers to understand the impact of MGN on distribution system operations.

Authors:

• Jamal Moshtagh
• Hassan Pourvali Souraki

Keywords:

• Distribution systems
• multi- grounded
• neutral
• three-phase four-wire
• ground.

References:

[1] J. J. Burke, Power Distribution EngineeringÔÇöFundamentals and
Applications. New York: Marcel Dekker, 1994, pp. 16-17.
[2] T. H. Chen, M. S. Chen, T. Inoue, P. Kotas, and E. A. Chebli, "Threephase
cogenerator and transformer models for rigorous distribution system analysis," IEEE Trans. Power Delivery, vol. 6, no. 4, pp. 1671-
1681, Oct. 1991.
[3] T. H. Chen, J. D. Chang, and Y. L. Chang, "Models of grounded midtap
open wye and open delta connected transformers for rigorous analysis of a distribution system,"IEEE ProceedingsÔÇöGeneration,
Transmission and Distribution, vol. 143, no. 1, pp. 82-88, Jan. 1996.
[4] A. P. Meliopoulos, J. Kennedy, C. A. Nucci, A. Borghetti, and G. Contaxies, "Power distribution practices in USA and Europe: impact on
power quality," in Proc. Int. Conf. Harmon. Quality Power, vol. 1,
1998, pp. 24-29.
[5] IEEE Recommended Practice for Grounding of Industrial and Commercial Power Systems, IEEE Std. 142-1991, June 1992.
[6] T. H. Chen,W. C. Yang, T. Y. Guo, and G. C. Pu, "Modeling and analysis of asymmetrical three-phase distribution transformer banks
with mid-tap connected to the secondary neutral conductor," Electric
Power Systems Research, vol. 54, no. 2, pp. 83-89, May 2000.
[7] J. C. Balda, A. R. Oliva, D. W. McNabb, and R. D. Richardson, "Measurements of neutral currents and voltages on a distribution
feeder," IEEE Trans. Power Delivery, vol. 12, no. 4, pp. 1799-1804, Oct. 1997.
[8] A. P. S. Meliopoulos, J. Kennedy, C. A. Nucci, A. Borghetti, and G.
Contaxies, "Power distribution practices in USA and Europe: Impact on power quality," in Proc. 1998 International Conference on Harmonics
and Quality of Power, vol. 1, pp 24-29.
[9] J. C. Das and R. H. Osman, "Grounding of AC and DC low-voltage and
medium-voltage drive system," IEEE Trans. Industry Applications, vol.
34, no. 1, pp. 205-216, Jan./Feb. 1998.
[10] Jim Burke and Mike Marshall, " Distribution System Neutral
Grounding," ABB Power T&D - Raleigh, North Carolina, 0-7803-7285-9/01/$17.00 (C) 2001IEEE.