Multiple Input Changeover

Why don't you provide more details like how many outputs,how many inputs,combinations required as well as a drawing/sketch of your proposal?.

Your right, basically I have 9 utility supplies say from building A and another 9 from building B and standby power for both buildings is going to be supplied from a single source. If a failure in building A should active the generator supplying standby power for building A.

Does it exist a single module taking multiple utility sources? or each utility supply has to have a change over switch.

Thanking you in advance

you need to install 18 auto changeovers in building A & B and to each of them lay a cable from the generator. If you have 1 changeover and 1 cable from generator to each building the generator supply too will pass through the utility's meter.

Yes that occurred to me but was just asking whether there exists one single autochangeover takibng more than 1 input. Thanks very much :)

Yeah. You can manage with a single change-over if the utility incomer is brought into the generator room. But the utility's meter will record the generator power too.

You have 9 "supplies" in each building? Don't you mean consumers?

Were is your utility power coming from?

yes they are two apart hotels having the same owner. i am refering to 9 supplies because there are 9 consumer units in each building.

Can you show us or explain what your existing setup is? Your sketch does not show the utility supply.

Is it advisable to connect one generator for the two buildings? The issue here is that the main supplies for the two buildings come from two seperate transformers.

How can I segregate bulding A from Building B with one set-up? I t does not necessarily mean that failure in mains A will be the same at mains B.

Thanking you in advance

Ryan

So Building A is fed from one source and serves 9 consumers and building B from a source other than A's source and is serving 9 other consumers?

You want to do this right?....

If source A fails then DG start and switch to A load

If source B fails then DG start and switch to B load

If source A and B fails then DG start and switch to A and B load

Exactly that is what I am trying to achieve.

The answer is, "They Do Exist"[p/]

I can't advise you any further because I am not sure what your technical background is.

Try redrawing your diagram. Instead of a block that says "changeover" replace it with some switches.

Simplify the drawing. The consumers don't need to be shown. You have Amains, Aload, Bmains, Bload and DG.

Consider a switching matrix....it may help you to understand

I think this can be done with two ATSs (automatic transfer switches), assuming the generator is large enough to handle the total A+B load.

If power fails to building A, ATS A switches building A to the generator, and likewise for ATS B.

Yes that is exactly what I want.

Tornado you can do what you are proposing if there exists one single supply cable per building. However this is an aparthotel and each consumer unit is fed by each respective mains cable.

Do all 18 of the units have their own transformers with their incoming services, or is there some larger grouping such as two transformers, each feeding all 9 services for each building?

they are grouped into two. BUILDING A supplied from TX A and Building B from TX B.

Then I'm still thinking that two ATSs will suffice, installed "downstream" of each transformer before the loads are split to the multiple services.

Cannot tornado , I cannot work transformer side cause it is suppliers property.

How about getting the supplier to do it? However, 18 smaller ATSs may be as economical as two larger ones.

Yes I know and your maybe right however the substation is general and it does not only feed our building but several others and as a policy the supplier does not perform any client's requirements within the substation.

Are these single phase loads connected to a 3 phase supply? 3 off Phase 1, 3 off phase 2 and 3 off phase 3 ..total of 9?

Is there a consumption meter at transformer A and transformer B (maybe relevant depending on answer)

How are the 9 feeds connected at each transformer?

Thanks for your interest it is very much appreciated.

Each 9 are coming from the supplier's fuse box, the fuse box inturn is supplied from one single cable (4-core-3phase) coming from a transformer. Amongst the nine feeds there is a mix of single and three phase supplies each having a consumption meter. The thing is that i can only modify from the meter onwards.

The same applies for building B. i.e.

TXB--->fuseboxB---> 9 B outgoings ------->9 B consumption meters----> 9 consumer units.

Regards

You will then need one ATS (AMF) per consumer.

DG control from one ATS on each distributed feed connected as a wired OR.

Why can't you access upstream of the meters? It call comes down to cost and 18 ATSs plus the DG power reticulation is not gonna be cheap or quick either.

What is your location?

Yes your correct. My location is Malta. As explained to Tornado upstream the meters is suppliers property.

Modification to a certain extent can be done between fusebox and meters but to do so i need to disconnect supply from transformer side and best thing of all, to reactivate the transformer after the modification I need to re-pay them for re-activation.

Modification inside the transformer is out of the question.

Dear All I thank you for your participation in this thread. I would like to ask a trivial question although it may be simple I never experienced such issue. Automatic changeover's logic is such that whenever one of the inputs fails (i.e. either mains or stand-by generator) it switches to the other. However how is the changeover's logic when the two inputs are active? (I know it is not supposed to be used like that in that case we use a bus tie/bypass)

thanking you in advance

Ryan

That is exactly the situation when the ATS is switched to DG at the moment when valid mains power is restored and detected..

At that time both inputs are valid. The ATS is configured with preference for mains. It will switch over to mains and the DG shutdown sequence will be invoked.

It does it.

This is no good for my case, since building A and B have different transformers and it does not necessary mean that if A is inactive B will be that (and vice versa). So powering the two buildings with one generator set is out of the question. However using ATS's for each meter is somewhat expensive. I queried whether there exists a multiswitch mechanism that can mitigate this problem. I searched and in my limited experience I never heard such units exist.

Any one has suggestions?

Thanks:)

You can do it with 2 ATS, IFF, you can access and modify upstream of the meters.

This will involve 2 new mains cables and installing 3 phase bulk metering for each building.

Each apartment would then be paying the landlord for their combined metered utility and generator power.

Still cheaper and easier than 18 ATS.

Is this feasible? Would the landlord want to get involved in reselling?

No, apartments are on long let and he is not going to sell the building.

I will try to work on this option. Thanks :)

Kind regards

Ryan

I mean reselling the bulk metered electricity to the sub-metered tenants not selling the building.

Ahh yes sure... I will verify this information with him and move accordingly.

Till the next one. kind regards

Ryan