The University of the Witwatersrand's (Wits') Johannesburg Lightning Research Laboratory (JLRL) is turning Johannesburg into a laboratory where live lightning events are measured and characterised through the use of high-speed cameras, direct current measurements, fast electric field measurements, field measurements and comparison with lightning location systems.

To build on Wits' pioneering research into lightning, and as part of the Wits Centenary programme that seeks to advance society for good, the JLRL has partnered with lightning protection company Dehn Africa and State-owned telecommunications company Sentech to support research into the protection of renewable energy systems from lightning.

The research involves installing a custom-built Dehn lightning current measurement device, which is intended for measuring lightning currents to wind turbines on the Sentech Tower, in Brixton, Johannesburg.

The research is being undertaken in partnership with Wits School of Electrical and Information Engineering lecturer Dr Carina Schumann, who made the first high-speed videos of lightning in Africa in 2017, as well as other postgraduate students and collaborators from around the world.

Southern Africa, as a climate change hotspot, is likely to see increased lightning activity and the study of lightning in Johannesburg is paramount to mitigate the dangers to human safety and economic sustainability, says Wits JLRL head and senior lecturer Dr Hugh Hunt.

“As we move more towards renewable energy systems, such as solar panels and wind turbines, that are highly susceptible to lightning damage, we have to learn how these are affected by lightning and how to protect them better,” he asserts.

“The best way to study lightning is to measure real lightning, which cannot be simulated in a high-voltage lab. Lightning is measured in flashes per square kilometre per year and Johannesburg averages a high flash density of 15 flashes per square kilometre a year, compared with Europe with an average of three flashes per square kilometre a year.

“It is rare to find a country’s economic and industrial centre in such a high lightning risk zone and Johannesburg is ideal to study lightning events because of its extremely unique characteristic of having a high cloud base, 6 km on average, making it possible for us to film a full lightning flash.

"No other location where lightning currents to tall towers are measured can correlate the measurements with high-speed footage as well as we are able to do in Johannesburg,” explains Hunt.

The JLRL made the first measurements using the Dehn detect device over the 2020 to 2021 Johannesburg summer thunderstorm session, high-speed filming and measuring 50 lightning currents. This has spurred Dehn Africa to donate a further R500 000 to the JLRL for future research around the protection of renewable energy systems from lightning.

The money will go towards installing more Dehn detect devices on high infrastructure in Johannesburg, as well as to provide bursaries for MSc and PhD students working on lightning protection research, and growing the research capabilities of the JLRL.

“It is an absolute pleasure to extend our partnership even further with Wits. As education and research are critical components to our economy, we as Dehn are truly excited to take the partnership to new levels," says Dehn Africa MD Hano Oelofse.

Wits School of Electrical and Information Engineering head Professor Estelle Trengove says the JLRL is one of the school’s flagship projects for the Wits100 celebration next year.

“Although much is known about lightning, there is much that we still need to learn. The JLRL is working at the cutting edge of lightning physics today, and the school is grateful for the generous donation from Dehn that has allowed it to expand this project further.

“At present, the Sentech Tower is equipped with current measurement equipment, but, in future, we would like to equip the Telkom Tower and other tall structures in Johannesburg with measurement equipment to get a more complete picture of lightning activity over Johannesburg,” she says.

Additionally, the International Conference on Lightning Protection, which is the premier lightning conference in Europe, will be hosted in South Africa next year owing to the successful bid by Wits Systems and Operations deputy VC and renowned lightning, high-voltage engineering and forensic engineering expert Professor Ian Jandrell.