The University of Queensland has patented an ingenious device to prevent lightning damage to sensitive electronic equipment such as computers, computer networks, telephones and microwave links.
The device, known as a transient blocking unit, acts as a barricade to isolate equipment from damage in a fraction of a micro-second. (A transient is a short surge of voltage or current).
The system limits damaging lightning current entering the system and disconnects the electrical load in less than 1/10th of one-millionth of a second, compared with 1/30th of a second for some conventional shunt devices.
The transient blocking unit was invented by Dr Richard Harris, who recently completed a PhD supervised by Professor Mat Darveniza in the University's Electrical and Computer Engineering Department .
The prototype unit has been patented by UniQuest Limited, the University's technology transfer company.
Professor Darveniza said the unit had attracted huge international interest at the first public announcement of its electro-magnetic capabilities at a recent technical conference in Rome.
'I've never had so many questions - this is a major breakthrough in transient protection,' Professor Darveniza said.
Dr Harris, who is employed with the Australian Maritime Safety Authority, completed a bachelor of engineering at the University of Queensland in 1984, and returned to start a PhD in lightning protection for electronics in 1992.
Lightning strikes cause millions of dollars damage to equipment each year, as well as human death and injury during storms.
Because of the increasing sensitivity of electronics, the smallest amount of inappropriately applied energy can cause electrical overstress to any electronic equipment.
'Equipment doesn't even have to be struck directly by such things as lightning to be damaged,' he said.
'Lightning can strike your building, or a site 10 kilometres away, and your equipment can be internally damaged without your realising it. All it needs is a connection between the strike and your equipment (such as a copper phone line).'
Dr Harris said a lightning strike could overload electrical systems with many 1000s of amperes of current unless preventive protective action was taken.
'Most people don't realise that much of the electronic equipment they use, such as computers and telephones, already has built-in conventional lightning protection,' he said.
The most commonly used type of protection was the shunt device, which diverted impulses away from the equipment.
Dr Harris and Professor Darveniza looked at existing protection systems to identify weaknesses and invent a device to give improved lightning protection.
The project examined the deficiencies of shunt devices and re-examined series devices (not normally in favour in conventional theory) to produce the improved protection system.
'The problem with shunt devices is that, as hard as you try, some of the transient energy always gets through,' Dr Harris said.
'The system that has been developed is a combination of blocking and diversion - the transient blocking unit isolates the equipment from the transient and allows the shunt device to divert the transient in the knowledge that the load is protected.'
Dr Harris said this combination approach actually simplified the overall protection while making it more efficient.
The University of Queensland group has commenced discussions with Griffith University researchers on further development of the integrated microelectronic circuit chips and individualised transistors for the device.
Dr Harris said the production version of the device was likely to be about the size of a transistor and could cost in the order of $1-$5. He said from all accounts, it had a huge potential international market.
'We hope to provide a better form of protection and save millions of dollars for communications technology industries,' he said.
For further information, contact Dr Harris, telephone 07 3835 3672, Professor Darveniza, telephone 07 3365 3775 or Jack Hennessy (UniQuest) telephone 07 3365 4037.
