ETAP Clarification

Not a good idea i think. Too much dependance on unrealistic theory. After all, there isn't an "Infinity" that you can lay your hands on is there? Two transformers will never be identical, and circulating currents will be unavoidable i feel. Not my field, just my humble opinion. One bus coupler is desirable.

thanks for your reply.. could you please give me valuable reason to argue with that people.. because as for my exp its compulsory of bus coupler..

Circulting currents, due to some small differences somewhere. Agreed that paralleling of sources is meticulously done, but in the event that these circulating currents do occur, you have the bus coupler which can be switched off.

Not my field really, let us hope you will get some better answers.

Hi,

If the transformer primary is a utility source(Electricity board substation) and you are assuming that is a infinite then considering the utility bus as a single bus (without bus tie) is acceptable.

If transformer primary feeder protective device (breaker)is in your scope of work, you need to model it seperately.

Regards,

Mari

The transformer primary is fed from VCB of 34.5kV intermediate switchgear. The supply for this intermediate Switchgear is from Ring Type distribution system in Switching station. From this switchgear Two seperate feeders also shall run to another plant.

Since, 34.5kV intermediate switchgear is feeding another plant, i beleive 34.5kV intermediate switchgear is owned by utility company(Electricity board).

If you know the maximum short circuit available in each bus need to model the 34.5kV Bus A and B seperately run the study with various scenario.

If you are assuming the short circuit contribution (as infinite source), study result shall not vary even if you considered a single 34.5kV bus instead of Bus A & B.

Apart from the above technical points you can insist the power system study vendor to model the system as per the actual condition so that anybody can understand the system easily in the future.

Regards,

Mari

Thanks a lot Mr, Mariappan, This intermediate switchgear shall be owned by client only not by electricity board. i already told vendor to do as per requirement. But he is not accepting that. Thats why I am asking to expert people for better idea..

Thing is The transformer is not directly fed by source, the source power shall come intermediate swgr first. From that swgr there are four outgoings. So only I am not accepting the single source like you..

Let me talk with him once again and see the result.

Once again thanks Mr. Mariappan..

There is nothing to say he has paralleled the transformers, they are just connected to the same source which 99% of transformers in the world are. If you cannot understand the model pay someone to review it rather then get "expert" comments from internet.

Er.....i do believe that BOTH the primaries and secondaries are connected together....the primaries to the infinite source, and the secondaries to the load's busbar. This used to be called 'paralleling' when i studied way back in 1965. Maybe things are different now?

Well you're drawing and words do not show that but you obviously have a lot of experience hence seeking advice. By the way who is getting paid to review contractors work, what is your role?

My friend, you should learn to read before writing.

1. i am NOT the Original Poster. The OP is rathakrishnan05. OK?

2. i am NOT seeking any advice. i am trying to give one opinion.

3. None of your business what my role is. Or who is getting paid. And how much. You have just started in CR4. Better learn some etiquette.

4. The diagram given by the OP shows the secondaries of the transformers connected to one bus. It is a logical assumption that the primaries are connected to the Utility. So they are paralleled. QED.

Mr.dbman kindly note nobody born in geneious in this world. people become genious by correcting their mistakes in past exp. If you can answer but dont discourage by using these type of words.. anyway thanks for your comment also...