Determining the Correct Electrical Resistance of Conductors in Power Systems Analysis

Authors

  • Massimo Mitolo Irvine Valley College, Irvine, CA, USA

DOI:

https://doi.org/10.13052/dgaej2156-3306.3961

Keywords:

Conductor resistance, electrical resistivity, ground-fault current, insulation material, maximum short-circuit current, minimum short-circuit current, nominal cross-sectional area, power system design, temperature coefficient, voltage drop

Abstract

The electrical resistance of a conductor varies with its material (e.g., copper or aluminum) and operating temperature.

This paper discusses the importance of determining conductor resistance at the appropriate temperature for voltage drop calculations, short-circuit current assessments, and ground-fault current evaluations in power system design. To normalize conductors based on their electrical characteristics, standards specify nominal cross-sectional areas uniquely associated with specific resistance values per unit length at 20∘

C. These resistance values, considering the metal’s resistivity, can be reliably measured, eliminating the need for potentially unreliable physical measurements, especially in stranded wires.

The paper highlights the need for conservative approaches in voltage drop calculations by considering maximum operating temperatures of insulation materials and outlines the methodologies for accurately determining the resistance for maximum and minimum prospective short-circuit currents calculations. Additionally, it addresses the significance of proper ground-fault currents calculations to ensure speedy protective device operation, thereby enhancing system safety and reliability. The principles and standards herein discussed are applicable across various global power systems, underscoring the universal importance of standardized practices in electrical resistance calculations.

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Author Biography

Massimo Mitolo, Irvine Valley College, Irvine, CA, USA

Massimo Mitolo (Fellow, IEEE; Fellow, IET), a distinguished scholar and scientist, has been bestowed the Knighthood in the Order of Merit of the Italian Republic in acknowledgment of his exceptional contributions to scientific endeavors that have brought great honor to the nation. He is renowned for his remarkable achievements in the field of electrical engineering.

Sir Massimo earned his Ph.D. in Electrical Engineering from the University of Napoli “Federico II” in Italy. His unwavering dedication and significant impact on the field have led to his recognition as a Fellow of IEEE “for contributions to the electrical safety of low- voltage systems”. Furthermore, he holds the distinguished title of Fellow from the Institution of Engineering and Technology (IET) in the U.K. and is a member of the IEEE-HKN Honor Society. Additionally, he is a registered Professional Engineer in both the state of California and Italy.

Dr. Mitolo serves as a Full Professor of Electrical Engineering at Irvine Valley College in California. In addition to his academic responsibilities, he is a senior consultant specializing in the domains of failure analysis and electrical safety. His extensive research and industrial experience revolve around the comprehensive analysis and grounding of power systems, as well as electrical safety engineering.

Dr. Mitolo’s expertise is reflected in his publication record, encompassing over 180 journal papers, as well as the authorship of several influential books. Noteworthy titles authored by him include “Electrical Safety of Low-Voltage Systems” (McGraw-Hill, 2009), “Laboratory Manual for Introduction to Electronics: A Basic Approach” (Pearson, 2013), “Analysis of Grounding and Bonding Systems” (CRC Press, 2020), “Electrical Safety Engineering of Renewable Energy Systems” (IEEE Wiley, 2021), “Smart and Power Grid Systems: Design Challenges and Paradigms” (River Publishers 2022), and “Simulation-based Labs for Circuit analysis.” (River Publishers, 2024).

His scholarly endeavors have garnered significant recognition, culminating in his inclusion in the 2020, 2021 and 2022 World’s Top 2% Most-cited Scientists List, as compiled by Stanford University.

Within the Industrial and Commercial Power Systems Department of the IEEE Industry Applications Society (IAS), Dr. Mitolo actively engages in various committees and working groups, demonstrating his commitment to advancing the field and fostering collaborative efforts.

Acknowledging his achievements, Dr. Mitolo has been the recipient of numerous prestigious accolades throughout his career. Notably, he has been honored with the IEEE Region 6 Outstanding Engineer Award and has garnered nine Best Paper Awards for his exceptional scholarly contributions. Furthermore, he has received recognitions such as the IEEE Ralph H. Lee I&CPS Department Prize Award, the IEEE I&CPS Department Achievement Award, and the James E. Ballinger Engineer of the Year Award from the Orange County Engineering Council in California.

References

IEC 60228:2023, “Conductors of insulated cables.”

CLC/TR 50480:2011, “Determination of cross-sectional area of conductors and selection of protective devices.”

IEC 60909-0:2016, “Short-circuit currents in three-phase a.c. systems - Part 0: Calculation of currents.”

NFPA 70:2023, “National Electrical Code.”

M. Mitolo, H. Liu, F. Freschi, M. Tartaglia: “Ground-Fault Conditions in Low-Voltage Systems. Potential Differences between Exposed-Conductive-Parts”, IEEE Industry Applications Magazine; May/June 2014, Vol. 20, No. 3; pages 34–39.

M. Mitolo: “Grounding the Neutral of Electrical Systems through Low Resistance Grounding Resistors: an application case”. IEEE Transactions on Industry Applications, Vol. 44, No. 5, September/October 2008, pages 1311–1316.

M. Mitolo, H. Liu, J. Qiu: “Ground-Fault Loop Impedance Calculations in Single-Phase Systems”. IEEE Transactions on Industry Applications, Vol. 50, No. 2, March/April 2014; pages 1331–1337.

IEC 60364-4-41:2005, “Low-voltage electrical installations – Part 4-41: Protection for safety – Protection against electric shock.”

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Published

2025-02-19

How to Cite

Mitolo, M. . (2025). Determining the Correct Electrical Resistance of Conductors in Power Systems Analysis. Distributed Generation &Amp; Alternative Energy Journal, 39(06), 1115–1124. https://doi.org/10.13052/dgaej2156-3306.3961

Issue

2024: Vol 39 Iss 6

Section

Renewable Power & Energy Systems