# Inductive influence on HV cable lines in urban and suburban areas

### Significance

The inductive influence of HV transmission lines on different nearby metal installations has been a research subject for at least six last decades. However, until recently developed methods were applicable only in relatively simple cases, when a scenario of right-of-way is very simple and when all relevant data are known. Even in such, relatively simple cases, because of complexity of the problem, a required problem solution frequently cannot be obtained without using modern computers.

The problem becomes extremely complex in the case of HV cable lines because they are, almost without any exceptions, laid in urban or suburban areas, where there are many others, known and unknown, metal installations. The usage of common routes (mainly street pavements) for various supply networks (electricity, water, gas, oil, telecommunications, etc) inevitably leads to their inductive coupling. Since these installations are mainly laid underground, many relevant data about them (constructive characteristic, mutual spatial position, including in some cases even and their total number) are uncertain or completely unknown. Thus, it is obvious that this problem cannot be solved by using only a calculation procedure. Also, the same or similar reasons prevent us to measure currents induced in the surrounding metal installations and the current passing solely through the surrounding earth.

The first method that enables compensation of deficiency of all unknown, but relevant data was developed by Dr. Popovic. The method is based on the measuring of the currents through one phase and through one neutral conductor of the considered HV line during the simulated ground fault in the supplied HV substation. Also, the calculation part of the developed method is based on a fictitious (equivalent) conductor substituting, from the standpoint of their inductive influence, all surrounding metal installations. It is imagined as a cylinder encompassing all conductors of the considered HV line along entire its length. However, this method requires exact measuring of the induced potential at the end of a provisory laid LV cable line that is practically impossible in urban conditions. Thus, this method is applicable only in the case of HV overhead lines.

Dr. Ljubivoje M. Popovic from Beograd (Serbia) managed to solve the problem of the inductive influence of HV cable lines in urban surroundings by developing the new version of its methodology for compensation of deficiency of all relevant but unknown data. The work is published in the journal, Electric Power Systems Research.

By using this version of Popovic’s methodology all necessary measurements are performed only within one of the substations at the line ends. Also, it is shown that the fictitious conductor can be determined in such manner that its physical appearance and spatial position coincide with any of the actual screens of the considered line. Thus, the inductive influence of all surrounding metal installations including the sheaths of the other two single-core cables can be expressed only through one equivalent line parameter, the longitudinal resistivity of one of the screens belonging to the considered cable line. Also, the author has analytically proved that the critical ground fault position from the standpoint of the inductive influence of an HV cable line is always the supplied HV substation. Finally, the most important is the fact that this version of Popovic’s methodology enables determination of inductive influence of HV cable lines in all practically possible situations.

Considering the easy feasibility of the method as it requires only relatively simple field measurements and calculations, Dr. Ljubivoje Popovic in a statement to Advances in Engineering highlighted that his method is also efficient and convenient in the cases when the inducing line is an HV overhead line, i.e. in the cases that are solvable with some of the already existing methods.

Ljubivoje M. Popovic was born in Markovac (at Mladenovac), Serbia, in 1944, graduated (1969) and received Master (1983) and Doctor (1991) degrees, all at the School of Electrical Engineering, University of Belgrade.

In 1969 joined the Electric Power Distribution Company of Belgrade, where he stayed until retirement in 2007.  In 1999 he was elected an associate professor at the School of Electrical Engineering, University of Belgrade and in 2010 he was elected an IEEE R8 Industry Lecturer (Industry Continuing Education Program).

At the beginning of his professional carrier, he worked on design of different power installations in the power distribution network of Beograd. At the end of the seventies, he moved to the Development and Research Department of the same company.

His research work has been mainly focused on the following topics:

• Grounding systems of HV substations located in urban areas,
• Ground fault current distribution along the overhead and cable feeding lines,
• Fault locator algorithms,
• Resonant phenomena in the transmission lines and transformer windings,
• Influence of metal installations surrounding the feeding line on the ground fault current distribution,
• Influence of electric-power lines on surrounding metal installations,
• Influence of surrounding metal installations on the transfer characteristics of distribution lines.

In addition to realization of the numerous studies and projects, in the area of power delivery, he published: over 50 research papers in international journals and proceedings of international conferences, by one chapter in two international scientific monographs. Also, he authored two scientific books under the titles: Actual Parameters of Power Lines Passing through Urban Areas and Practical Methods for Analysis and Design of HV Installation Grounding Systems.

Some of his papers and research results have had an impact on the following IEC publications: Technical Report IEC 60909-2, Ed 1(1992-09) and IEC standard 60909-3, Ed 2 (2003-09)), and was especially highlighted by: ”Vertical News”, ”High-beam Research”, ”High-beam Business”, ”Goliath Business News” and ”News-edge”. Two of his papers published in 2014 have been selected by ”Renewably Energy Global Innovations” as the key scientific articles.

He was elected a member of the IEC Technical Committee – IEC/TC73- Short Circuit Currents from 2004. A member of IEEE since 1987, he became Senior Member in 1991 and was the Chair of IEEE PES Serbia and Montenegro Chapter from 2002 until 2009.

He received: national ”Nikola Tesla” Award in 2006, IEEE PES Chapter Outstanding Engineer Award, and Certificate of Appreciation for Notable Services and Contributions towards advancement of IEEE and Engineering Professions.

### Reference

Popovic, Lj. (2019). Inductive influence of HV cable lines in urban and suburban areas. Electric Power Systems Research, 176, 105944.