The Use of Cable to Link Two Bus's directly in a MV Distribution Subst

[jhonwyn73]

Greeting to All,
We have an expansion, and there is a plan to supply a new 35kV bus directly through a cable from an existing 35kV bus. The distance is about 20m and the demand is about 30MVA. So, both bus's will be connected directly through a cable and two CB's (no transformer).

It is a new idea, and I would highly appreciate if you can help to know the impact or precautions to be considered. Also I would like to know wither such connection is accepted by standards or not.

Fyi, majority of load are motor drives.

Thanks in advance for your help.

 

[Marmite]

This is quite a common arrangement at both 11kV and 33kV for us, particularly where there are space constraints preventing a long switchboard, or where we want to segregate the switchboards for increased security. We use single core cables for the interconnector, and a simple high impedance unit protection scheme to protect the cable link. You might want to consider a mechanical interlocking scheme for earthing the busbar for work, depending on the design of the switchgear and your local safety rules and operational practices.
Regards
Marmite