Disconnection times on a system if a stand by generator is used

On a fully designed power distribution system, clearly the fault levels, earth loop impedances and ultimately fuse disconnection times are determined by the system parameters Transformer %Z etc one or two in parallel for min and max fault levels levels. What needs to be considered when bringing on a stand-by generator, clearly all Fault levels, Earth loop impedances and consequently fuse disconnection times would change because of the Generator parameters. How would you design in these new parameters, bearing in mind that disconnection times on a large system may no longer be achievable 

Parents
  • Wait to see what the "big boys" have to say (my personal experience is on smaller scale systems that yours sounds to be), but I would have thought that increasing cable c.s.a.s wouldn't usually be the way to go - but rather choosing different protective devices and/or sacrificing an amount of discrimination (worst possible case would be an RCD or MCCB+earth leakage trip on the output of the generator).

       - Andy.

Reply
  • Wait to see what the "big boys" have to say (my personal experience is on smaller scale systems that yours sounds to be), but I would have thought that increasing cable c.s.a.s wouldn't usually be the way to go - but rather choosing different protective devices and/or sacrificing an amount of discrimination (worst possible case would be an RCD or MCCB+earth leakage trip on the output of the generator).

       - Andy.

Children
No Data