‘Time warp’ tech speeds up powerline repairs

ergon energy, essential energy, electricity networks, powerlines, REFCL, Powercor

Radical new ‘time reversal’ technology developed by Monash University and Swiss researchers can reduce the period taken to locate powerline faults and help ease community impact in areas at risk of bushfires.

An international research team involving Dr Reza Razzaghi from Monash University’s Department of Electrical and Computer Systems Engineering has successfully tested their fault location technology in Switzerland, with further trials to continue on Australian power lines.

A patent for the latest innovation in this technology has been filed by Monash University, and Australian industry has expressed interest in upscaling it for further tests on rural powerline networks. 

In contrast to current methods, this technology requires only a single measurement point installed at a substation which can identify a precise fault in the power line, to within 10 metres, in a few seconds to minutes.

Victoria currently adopts Rapid Earth Fault Current Limiters (REFCLs) across its high-risk rural power networks, which limits the energy supply when a fault occurs to mitigate any bushfire risks.

However, REFCLs cannot precisely determine where a fault is located, meaning restoration crews can spend hours patrolling hundreds of kilometres of power lines in order to find the problem before they can fix it.

Thousands of people can be without power for several hours in extreme heatwave conditions as a result of this time lag. Local communities welcome the reduction in fire-risk, but can suffer heat stress casualties due to the long power outages that are sometimes required to prevent fires.

Related article: The Aussie invention stopping faults and fires

“This innovation aims to ease the community impact of current technology that helps to prevent fires. The problem we have is when a network fault is detected, the REFCL activates to prevent the fire but it can’t find the fault,” Dr Tony Marxsen, Research Associate in Monash University’s Department of Electrical and Computer Systems Engineering, said.

“So what ends up happening is that a large number of people are without power for upwards of five hours on a 45 degree day.

“This technology offers the hope that faults can be pinpointed quickly, reliably and safely, to, above all, reduce the impact on customers in very high stress conditions.”

The ‘time reversal’ technology comprises three steps: firstly, the fault signals are measured; the fault locations are then defined and the time-reversed signals are injected to a computer model of the network; and, finally, the fault current at a guessed location is evaluated to identify the most probable location of the fault.

“Imagine a swimming pool with sensors around its perimeter. If a stone was dropped into the water, the ripples would hit the sensors, and these sensors would record the waves generated by this stone drop. The ‘time reversal’ technology can find the location of the dropped stone by (in a computer model of the pool) reversing the direction of the waves measured by the sensors,” Dr Razzaghi said.

The technology will allow distribution network operators to locate faults in power lines quickly and allow the fault to be found and repaired faster.

Faults in electrical distribution networks are one of the primary sources of major bushfires in Australia. On Black Saturday, five of Victoria’s 11 major bushfires were started by power line faults. Media reports blamed a power network fault for a 2019 fire in South Australia that burned more than 20,000 hectares, destroying many houses and local businesses.

“Rather than bypassing REFCLs and re-energising faulty networks and risking a fire, this technology can help to pinpoint the fault location after the operation of REFCLs,” Dr Razzaghi said.

“This radical new technology has the potential to save lives and ensure Australia is best prepared to prevent and tackle any catastrophic incidents that might arise as our country continues to get warmer and drier,” Dr Marxsen said.

Further research in currently being undertaken to adapt this technology to Australian power networks.

The study, titled ‘Time reversal applied to fault location in power networks: Pilot test results and analyses’ was a collaboration between Dr Reza Razzaghi (Monash University), and Mr Zhaoyang Wang, Dr Mario Paolone and Dr Farhad Rachidi (Swiss Federal Institute of Technology Lausanne).  

Other partners on this project include the Monash Energy Institute, Monash GRID Innovation Hub, AusNet Services and IND Technology.

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