G59 and generators

[Leesparkykent]

I'm looking at a job at the mo where its looking like there is going to be backup/standby generator. Just wondering if anyone has done a similar install and been involved with the paperwork side of things? As its bigger than 16A per phase would a G59 relay have to be installed, application to UKPN, G59 witness testing etc? or am I barking up the wrong tree. Cheers Lee

 

[jackhammerJIM]

surely there will be a changeover switch so nothing is fed back to the grid ?

 

[jackhammerJIM]

What is G59? - Electrical Engineering - http://www.connectingindustry.com/ElectricalEngineering/what-is-g59.aspx

 

[Leesparkykent]

surely there will be a changeover switch so nothing is fed back to the grid ?

Yeah there will be an ATS but does this satisfy the requirements alone? I was just reading this http://www.shentongroup.co.uk/wp-content/uploads/2013/08/G59-Testing-Commissioning.pdf The bit where it says "some common myths". found the document from this video.

 

[jackhammerJIM]

your not running in synchronisation with the mains .

 

[Wilko]

Hi Lee - I have not done this but I have now reviewed the info to hand and my take is summarised by an excerpt from their myth busting doc :
”I don’t need G59 Protection unless I intend to export power to the grid” Wrong. If you have any form of generator where the output is connected to the electrical systems in your building, and thus to the grid, you must protect it with a G59 relay device.
So if the generator is NEVER connected to the grid then G59 approval is not required. Perhaps others can confirm ? Or correct

 

[Leesparkykent]

Hi Lee - I have not done this but I have now reviewed the info to hand and my take is summarised by an excerpt from their myth busting doc :
”I don’t need G59 Protection unless I intend to export power to the grid” Wrong. If you have any form of generator where the output is connected to the electrical systems in your building, and thus to the grid, you must protect it with a G59 relay device.
So if the generator is NEVER connected to the grid then G59 approval is not required. Perhaps others can confirm ? Or correct

I'm going to make some calls tomorrow to find out some more info, was just interested in others take on it. The only thing to stop the generator exporting to the grid in the event of mains failure is the automatic change over switch. I would of thought the DNO would require some other kind of safety feature that meets certain requirements, other wise the poor sod working on the network might get a belt

 

[freddo]

The automatic changeover contactor pair should be mechanically linked so it is impossible for the 2 supplies to ever be connected together, even if both coils were powered at the same time.

 

[Lucien Nunes]

Agreed - the G59 protection is required if the generator can operate in parallel with the mains, to island the generator if the mains fails. If the generator is for backup use only and cannot operate in parallel, a transfer switch or automatic transfer panel is required. The operator may require details of the panel to prove compliance and ensure it provides adequate isolation between the two sources of energy.

 

[Leesparkykent]

Agreed - the G59 protection is required if the generator can operate in parallel with the mains, to island the generator if the mains fails. If the generator is for backup use only and cannot operate in parallel, a transfer switch or automatic transfer panel is required. The operator may require details of the panel to prove compliance and ensure it provides adequate isolation between the two sources of energy.

cheers Lucien.