Ot Generator Installation

davefinic · Aug 2, 2007

I have a customer who needs a power upgrade from 70 KVA to 120KVA and is having problems getting a supply upgrade as there is a lack of power in his area.
He has suggested that he can get an 80KVA generator brand new at a good price as a contact of his has shipped them from China.
My question is can he run this alongside his existing incoming supply, with both supplies fed into the same 200A isolator, im thinking that he may need something to stop him feeding back into the grid.
Also he would rather use the generator at full output and top up with the incoming supply as his plant produces biodiesel.

Oakley · Aug 2, 2007

1. Consult the power utility in his area. They may be able to offer him a deal, in addition, they can give guidance what they would require.

2. Consult a fuel supplier - ensure constant fuel delivery.

theDave2 · Aug 2, 2007

davefinic said:
... with both supplies fed into the same 200A isolator ...

What the heck is a "200A isolator" ???

But in any case, the answer is NO. You cannot do it that way. You can run a load(s) from the utility OR from the generator.

If he cannot get a service upgrade and wants to use the generator, then the loads must be split apart. If he needs to select which supply to use, then a transfer switch is needed.

Have him consult a qualified company to do this as his sizing is most likely off and not accounting for motor starting loads.

raviv · Aug 2, 2007

try to gogel embededd generation......this isn't going to be simpel or cheap but it is possible.

sory for my bad spelling

davefinic · Aug 2, 2007

theDave2 said:
What the heck is a "200A isolator" ???

This is the isolator at the origin of his supply (electric meters) we have fitted it ready to take a larger incoming supply that was going to be installed by the electricity supply company, but now he wants to buy a generator because its cheaper.

BTW I have calculated his maximum demand based on all the information given to me of the plant to be installed and taken into account starting loads after asking for all loads and starting methods from the machinery manufacturers.

I have explained to my customer that I am not familiar with generators although I have worked on generators that have a changeover either manual or automatic. I am also talking to generator experts but thought I would ask here incase anybody has had expieriance of this type of installation.

Phill77 · Aug 2, 2007

Your client needs to speak with his Distribution Network Operator (DNO) for some guidance. I believe they will need to comply with the Electricity Safety, Quality and Continuity Regulations, and G59/1 by following ETR-113.
In brief this means having a way of automatically isolating the generator from the grid in the event of under/over voltage or frequency, or loss of mains.

So no, you can't simply feed two supplies into one isolator.

The G59/1 contract will allow export of power, so they could run the generator at full power and be paid for any export/reduce their bill. That is unlikely to be cost effective though, and is likely to be better to use the generator to top up the supply, and sell the biodiesel produced.

Have a look at www.energynetworks.org

Hope thats of some help,
Phill

davefinic · Aug 2, 2007

Thanks for the link phill77

I didnt think it would be possible to feed into 1 isolator but my customer asked me to find out.

milldrone · Aug 2, 2007

Phill77 said:
In brief this means having a way of automatically isolating the generator from the grid in the event of under/over voltage or frequency, or loss of mains. Phill

In my area of the country this means the utility has control over this automatic switch.

Phill77 said:
The G59/1 contract will allow export of power, so they could run the generator at full power and be paid for any export/reduce their bill. That is unlikely to be cost effective though, Phill

Our very old contract (up for renewal soon) has us selling power for 2.5 cents KWH and we buy power for 7 cents KWH.

BobB · Aug 3, 2007

It can be done with a suitable generator/co-generation controler(s) and ACBs or motorised circuit breakers, provided the local authority will allow it. It is called co-generation. I have done sevaral of these jobs at both LV (415 volts) and HV (11kV and 22kV). I prefer a local controller in Ozz but Woodward can help.

Importantly, the control system must be 24VDC (battery supply) and the ACBs/motorised circuit breakers require proper protection. If the generator fails or the set starts to export, generally the circuit breaker MUST be opened immediately. The local authority would probably require overcurrent (short and long time), reverse power, reverse var and possibly earth fault and/or differential protection. The cheap generator will not look cheap by the time all the control system and a new power switchboard are built in.

Ot Generator Installation

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