Compact Overhead Line Design

This Green Book provides the design engineer with an understanding of the electrical parameters and methods required in designing compact AC and DC lines. 

Compact AC and DC lines are becoming increasingly necessary due to the limitation of right of way access and the need to upgrade power transfer in existing, narrower line corridors. Another requirement for compact AC lines is the lower impedance permitting increased power flow.

For DC power lines, increased power flow can only be realised by increasing the current through the conductors and/or increasing line voltage. In AC it can also be achieved by bundle expansion and phase compaction due to the variation of impedance. The effect of compaction on AC and DC lines is not identical as with the constraints. The Green Book covers the theory relating to the constraints such as corona, audible noise, insulation coordination, electric and magnetic fields and others for both AC and DC lines.

In addition to the theory, the Green Book includes actual calculations of electric parameters for different pole (DC) and phase (AC) configurations. Standards applied by various countries are tabulated for easy comparison of practices internationally.

Case studies on line compaction designs for both AC and DC are described with relation to pole compaction, pole rearrangement and phase configuration. Voltage upgrading is also treated in this book, and some case studies for both AC and DC are considered.

Dr. Rob Stephen was born in Johannesburg South Africa. He holds B.Sc., M.Sc., MBA degrees as well as a Ph.D. in overhead line design. He retired from Eskom in 2020 where he held the position of Master Specialist in the Technology Group responsible for distribution and transmission technologies of all voltages covering both AC and DC. He is Past Chairman of CIGRE Study Committee B2 on overhead lines and has held positions in CIGRE of Special Reporter and Working Group Chairman (including that for compact AC lines) and has authored over 100 technical papers. He was International President of CIGRE from 2016-2020. He is Fellow of the South African Institute of Electrical Engineers and was awarded the President’s award in 2016. He is currently Academic Specialist Consultant at the University of Kwa Zulu Natal, Durban.

Javier Iglesias was born in Madrid, Spain. He holds B.Sc. and M.Sc. degrees in Mechanical and Electrical Engineering from the “Universidad Pontificia Comillas – ICAI”, as well as other postgraduate programs on Project Management and Executive Management. He has over twenty-five years’ experience in transmission lines, from different positions and companies. In 2002, Javier joined Red Eléctrica de España, where he now is responsible of projects for the transmission system in Spain (400 and 220 kV lines and substations), being in charge of the coordination, engineering, environmental studies, construction works, supplies, permits, authority licenses and commissioning. He has co-authored over twenty technical publications related to transmission lines, has been Convener of two CIGRE Working Groups and has participated actively in more than fifteen. In CIGRE, he has held positions of National Representative for Study Committee B2, Special Reporter at the Paris Session 2016 and Chair of various conferences and workshops. He received the Technical Council Award in 2018. Now, he is Chairman of the Technical Advisory Group on “Electrical aspects of overhead lines”, President of the Spanish National Committee and Member of the CIGRE Steering Committee.