Electricity + Control September 2018

DRIVES + MOTORS + SWITCHGEAR

The electrical distribution industry is experiencing workforce, financial and regulatory pressures that require new designs to

ing a conductive layer to the outside of the insu- lating layer, which, when set to ground potential, creates a ground shield around each phase of the switchgear. This enhanced version is called a Shielded Solid Insulated System (2SIS). This in- novative additional step means that not only are there no exposed live parts, but every interior por- tion of the switchgear is at ground potential. The ground layer minimises phase-to-phase in- teraction, reduces the likelihood of arc flash and helps to protect the insulating material itself. The ground shield behaves like a Faraday cage, min-

protection, smaller footprint requirements and a higher level of safety. The latest design of medium voltage switchgear addresses these issues through an innovative insula- tion system called Solid Insulated Switchgear (SIS). This system uses moulded epoxy insulation as the principal source of dielectric strength. A key benefit of SIS is that it allows for a decreased air gap be- tween the phase conductors, which reduces equip- ment size. It can also eliminate exposed live parts when used throughout the switchgear’s interior. This insulation can be further improved by add-

meet modern applications.

Electricity + Control

SEPTEMBER 2018

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