ASL and generation

[Cerkit]

Hi,

A distribution network question.

Does anyone know why it is not generally allowed to use Auto-Sectionalising links on spurs which have generators connected? This is for an HV feeder (eg 11kV overhead line).

Thanks

 

[Marmite]

Probably because the ASL wouldn't necessarily clear the downstream fault, which could be maintained by backfeeding from the generator, or the remaining two live phases. If the generator is connected via a delta star transformer with the delta facing the generator and the star feeding out to the 11kV line, then the transformer would try to feed the open circuit phase by circulating current in the delta.
Regards
Marmite

 

[marks1080]

Generally, utilities try to avoid islanding systems.