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The 50/51/67N on the primary and trip the transformer upstream breaker. and there is no-load except the transformer in the 3km side.

rbulsara I agree with you that fuses is enough for small rating transformer but this may be only for dry transformers. But in the oil transformer can you explain if it is enough such fuses why the transformer manufacturer equiped the transformer with all the mechanical protection like...

Dear smallgreek, What do you mean by a bit much? Do you thing that because the xfmr is 500KVA that is mean we don`t need to give it the respect. For me I think the protection for the lower elecrtrical equipment sizes is very important like the huge one. Or if any one has different opinion he...

The XFR is 500KVA. Any way you think that the optical cable will be reliable to cary protection signals or it is recommended to carry the protection signals on hard wires.

Hi guys, Thanks so much for your valuable replies. You know the case is a cost issue because the transformer is around 3KM away from the upstream MV circuit breaker and the contractor should lay control cables to send the alarm and trip signals. Thanks

Hi rbulsara, As i said before it is the logic to trip the upstream to protect the transformer internal fault. but,imagain you are discussing with your subcontractor and he said it is enought to trip the down stream and no need to trip upstream and you should proof to him the right connections...

Yes, that is which i`m belive in that we should trip the upstream but again my question is (is there is any standard we should follow and force us to trip the upstream?)

Hi, For the MV/LV oil transformer , the transformer mechanical protection like (Buchholz,oil temp,saftey pressure,....) the trip contact from all those protections are used to trip the upstream MV breaker for the transformer. Is it possible to use this contacts to trip only the downstream LV...

Our priemover is diesel and the generator capacity is 2000KW and 6.6KV

The setting is 10% for 2 sec.

Yea Simply the reverse power was activated and associated with under frequency. and for Mr.waross the synchro was on auto mode and the schenchro was already done but one generator trip after 10 seconds and another clarification required the reverse power is will known for the generators but...

Yea,we are at the pre-commissioning phase and there is no actual load and we arleady did the test and one of the generators fail by reverse power 10seconds after synchro. and we still investigating up to now.

How long i can synchronize two generators each 2MW without loads? Is there is condition to connect generators in parallel without load or the synchronization will fail due to no-load operation.