Electrical engineering firm Lucy Electric launched its modular Aegis36 ring main unit at Africa Utility Week, which took place in Cape Town last month.

The unit is designed for switchgear of up to 36 kV installed in secondary distribution networks and particularly for renewable-energy projects.

Lucy Electric marketing director Phil Dingle explained to Engineering News at the event that the focus to design the unit for renewable-energy installations was owing to the significant rise in the output of wind and solar installations, which impacted on the cost effectiveness of 36 kV switchgear.

He added that switchgear with a 36 kV rating had effectively become the investment “sweet spot” for renewable-energy installations.

The Aegis36 is designed for increased safety, owing to the two ring switches and a circuit breaker, all internally placed in a robotically welded, hermetically sealed stainless steel tank to ensure the highest level of fabrication accuracy and consistency.

The circuit breaker feature allows for a portion of the electrical network to be isolated, thereby making it safe for maintenance teams to work on the particular area.

The unit also has a switching sequence that prevents an operator from gaining access to the cable compartment until it has been earthed. It also has an earth and test access point, allowing for cables to be tested more safely.

“The cable compartment, which is where the cable terminations are located, is a likely area of a potential failure,” Dingle noted. For example, failures might occur, owing to the way in which an operator had terminated the cables, perhaps scraping the insulation surrounding the cable, which, in turn, might cause deterioration to the integrity of the cable, subsequently resulting in an internal arc flash, he explained.

The hermetically sealed tank ensures that sulphur hexafluoride, a potent greenhouse gas that is commonly used in electrical applications to prevent electrical discharges, does not escape into the atmosphere.

The unit also contains burst flaps, which enables the unit to purge any flames out of the unit and away from operators in the event of an arc flash.

“From an operator’s point of view, in the event of an arc flash, the structure of the Aegis36 is designed to withstand the pressures such as a flash creates,” said Dingle, concluding that the burst flaps also prevented flames from reaching the operator.