We have an 11 kV open ring system, 11 kV incoming from supply authority, this feeds on to a busbar via circuit breakers. In parallel onto the same busbars is an 11 kV supply from a 1.5 MVA CHP unit via a 400/11 kV step up transformer. And also in parallel with this is a 3 MVA 11 kV diesel generator. The busbars is split with a normally closed bus coupler, with the CHP & Genset on one side and the supply authority on the other side. The coupler is normally closed, thus paralleling up the supplies. Both sides of the busbar supply an open ring system via circuit breakers. Normally only the supply authority & CHP run in parallel with the generator providing backup. But there are times when all three can be running together. Now if we want to add a second CHP system as another source of supply, what needs to be considered? Will this second CHP contribute to the fault level of the system? G59 protection would also need to be provided on this unit. What impact would this CHP to the overall protection settings on the ring? Appreciate a none to complicated reply.
- posted
17 years ago