Parallel operation of Gens

[chaterpilar]

We intend to buy 10nos. 1600kva Cat gens (60Hz) for a Load of 12 MVA and are looking at 3 options...

 

a) make all 10 in sync and feed the common to Distribution board or...

 

make 2 sets of 5 Gens each (in sync) and feed it to Distribution board, with a bus coupler

 

c) Is it possible to furthur synchronise the two banks of 5 gens and then close the buscoupler.

 

Please give your views about advantages and disadvantages of each option.

 

Thanks

 

Chaterpilar

[Guest]

Suggest you contact the Experts ie

 

FG Wilson - Larne - N. Ireland.

mailto:sales (at) fgwilson (dot) com

[chaterpilar]

Marke,

 

 

I am waiting for your valuable opinion.

 

 

regards,

 

Chaterpilar

[GGOSS]

Hello Chaterpilar,

 

Just a quick note to let you know Marke is travelling overseas this week and may not have ready access to the internet.

 

Unfortunately I do not have enough gen-set experience to provide you with any sound advice. Hopefully some of the other forum members will be able to assist you further.

 

Regards,

GGOSS

[Guest]

Hello Chaterpilar,

 

What you are proposing to do is not at all difficult, and I have commissioned a few multiple parrallel diesel generator sets. If you want to organise all the gerneators on to a single bus that is fine, or if you want them on two buses that is also fine. Automatic synchronising, load control and scheduling on/off of the generators as the load changes is also easily done.

 

16MVA at 400V is going to require some very big bus bars, you may have to run a single bus as you might not be able to get a bus tie breaker that can handle the fault current, or are you going to have MV generators at 3.3kV or higher?

 

Is the generation going to supply the load in isolation or will it run in parrallel with a utility network?

 

Regards

Niallnz

[chaterpilar]

hello,

 

Thanks for your reply.

 

well the generators will be synchronised and then 400v outputs will be sent to 400/13.8kv step up X-mer

 

Each gen will have 1 step up X-mer.

 

The 13.8kv sync bus will have utility supply with castle interlocks

 

I wanted toknow which arrangement will be easier and good for reliability 10 gens in sync or 2 banks of 5 gen in sync and then the two banks in sync.

 

regards

 

chaterpilar

[niallnz]

Hello Chaterpilar,

 

Just to confirm, each generator will be directly connected to their own step up transformer, therefore the synchronising will take place across the 13.8kV CB. The 13.8kV bus will also have 1 only connection to the utility.

 

In this case I would connect all 10 gens onto the one bus. Why are you interlocking the utility supply? I would set up the generator controllers to also control the utility breaker, and control the generator output for zero power import/export across the utility CB if that is what is required. The generator controllers will be able to synchronise the gen bus to the utility upon the return of the utility supply after a failure. Alternatively the control can be bumpless transfer between the utility supply and the generator supply, ie which enough generators are on line to take the local load the utlity CB will be opened.

 

I think that 10 gens one to the one bus will be easier to set up and more reliable.

 

BR

Niallnz

[chaterpilar]

Hello Niall,

 

The synchronisation will take place at 400 volts ( LV side of the step up transformer).

 

We are in favour of 10 gens in sync.. but the issuethere is if the Sync panel develops a fault ...then all gens are down..

 

If you do 5 in sync..and then the other 5 in sync then atleast 5 gens are in operation even if 1 sync panel is down.

 

Actually syncing..10 gens is easier...but reliability of Sync panel becomes a risky factor.

 

We are not going synchronise gen supply with utility supply..they are just mechanicalyy interlocked ( Castell lock)

 

regards,

 

narayan

[niallnz]

Hello Narayan,

 

Typically in power stations the synchroniser is in a trolley that is wheeled to each generator control panel. And a synch trolley can be a simple as three lights, so the chances of it developing a fault that can't be fixed in a hurry are very low. So I take it that this power station will be manually operated?.

 

Personnally I would be controlling these gensets with a Woodward EGCP-3 on each unit. The EGCP-3 is a synchroniser and load controller so no sync panel required. The EGCP's communicate between each other and can start/stop the generators to match the load. The EGCP can also automatically balance out the running hours on the gens amongst other things.

 

I would also do a true unit connection of the generator and the transformer and sync across the HV CB, but remember to install and a CB in the generator field circuit which can be tripped by the generator/transformer protection. It may not seem like much but you save yourself the cost of the LV switchgear, terminations, panel etc and when a generator is off line your not wasting energy keeping a transformer warm. There are no transformer inrush issues as when you excite the generator you also excite the transformer and this done from 0volts.

 

I'd be happy to design supply and commission a generator control system for you.

 

Cheers Niall

[Seema K]

Hello Niall

 

First of all apologies for intervening.

 

Cuntinuing the conversation, have you considered the impact of shortcircuit level of the common busbar? NGR?

 

Regards,

S

 

Hello Narayan,

 

Typically in power stations the synchroniser is in a trolley that is wheeled to each generator control panel. And a synch trolley can be a simple as three lights, so the chances of it developing a fault that can't be fixed in a hurry are very low. So I take it that this power station will be manually operated?.

 

Personnally I would be controlling these gensets with a Woodward EGCP-3 on each unit. The EGCP-3 is a synchroniser and load controller so no sync panel required. The EGCP's communicate between each other and can start/stop the generators to match the load. The EGCP can also automatically balance out the running hours on the gens amongst other things.

 

I would also do a true unit connection of the generator and the transformer and sync across the HV CB, but remember to install and a CB in the generator field circuit which can be tripped by the generator/transformer protection. It may not seem like much but you save yourself the cost of the LV switchgear, terminations, panel etc and when a generator is off line your not wasting energy keeping a transformer warm. There are no transformer inrush issues as when you excite the generator you also excite the transformer and this done from 0volts.

 

I'd be happy to design supply and commission a generator control system for you.

 

Cheers Niall

[martin]

Hi There,

Have read the post with interest!

I would say buy the best system that has the best local service support for you're area/region in the world. Whilst Woodward EGCP-3 has been mentioned as a solution, which I'm not saying is correct, is your local rep/service people able to handle this?

Had huge problem setting-up in Indonesia rig a system on this brand and found the support.....wanting!!!!

I personally use a Heinzmann, out of Germany....again lot of software,......I guess I'm saying for such a complicated system speak to the suppliers in your region and ask for references of their stuff actually working.

Regards

Martin