LV generator Earthing - UK Regulations

[musaUKPN]

Hi all,

Should the star point (neutral) of LV embedded generator that runs long term parallel with utility be directly connected to then customer's LV earth?

The situation is that the customer has LV (PME) supply from utility transformer. At site customer has installed a CHP LV generator which will run parallel with utility all times. On certain occasions the CHP could export power onto utility's network. At customer's site the utility earth electrode and its own earth system are bonded together.


We have following options:
1. star point left ungrounded to counter act circulating harmonics
2. star point grounded through resistance to counter act circulating harmonics
3. Solidly earth star point and allow harmonic current to circulate

I would require explanation to above question both from technical as well as UK regulation prospective.

Regards,

musa UKPN

 

[ScottyUK]

I suggest that you speak to the DNO concerned, they will likely have their own set of requirements which will be based on ENA recommedation G59/2 unless this is a really small installation. Failing to engage the DNO early is usually a good route to problems later.

 

[ppedUK]

As Scotty says, speak to the DNO first, but i'm quite sure they will want star point of embedded gen isolated from earth. With a PME supply, they may also want Neutral of gen isolated from their supply also, this is shown in ETR113 which the DNOs usually adopt.

If your handle indicates that you work for a certain power network company in the UK, then I would expect you to know this already.