Explain these comments on a Gary Does Solar video?

[JohnMo]

13 minutes ago, Dave Jones said:

the problem with self install is no MCS paperwork. Octopus wouldnt accept any export from me (for payment) without it.

I just paid the £250 will break even in a year and still way cheaper than a mcs install.

[Dave Jones]

Just now, JohnMo said:

I just paid the £250 will break even in a year and still way cheaper than a mcs install.

 

i tried also, octopus refused without MCS cert. How did you manage it ?

[JohnMo]

The operators don't seem to understand the process. You have to go through a dedicated part of the website

https://octopus.energy/help-and-faqs/articles/export-without-mcs/

[-rick-]

50 minutes ago, joth said:

Fair point 🤣

What I was trying to say was it would be unnecessarily complex to try and design something elaborate into the standards requiring "intelligent" collaboration across a system of inverts communicating with each other, when you can achieve it within the existing pretty dumb standard.

 

100% though knowing this country the 'smart' solution requiring 24/7 internet connectivity is what will get proposed at some point.

[Beelbeebub]

1 hour ago, -rick- said:

 

This is exactly what's being proposed by the grid (see the link I posted earlier). Reducing the minimum acceptable voltage to 207V.

 

Modern equipment shouldn't really care about the voltage being that low (the minimum voltage in Europe is 207V and almost all electronics we have bought in the last 30 years have been designed to work in that market). Link suggests a 4% reduction in resistance heating output, slightly dimmer lights. Most tricky issues being non-inverter driven motors and UPSes with to high a brown-out setting (likely can be adjusted).

Yes, if the can widen the window by lowering the bottom it will help. 

 

Current UK is 240 +10/-6 ie 216 to 253

Europe is 230 +/-10 which is 207 to 253

 

I think our asymetric limit was fudge when we standardised with Europe and everyone actually stayed the same. 

 

Bu as you say - all modern equipment will function absolutely fine at lower voltage. 

 

There might be an issue with higher currents for constant power devices at the lower voltage. 

 

I noticed my inverter (solax) has a power based export limit. Eg 3.6kw whilst my DNO specified a current limit (16a).

 

The lower minimum voltage could mean those of us with power based limits will have to assume 207v ie 3.3kw rather than being able to set 3.6 or even 3.9kw.

[-rick-]

5 minutes ago, Beelbeebub said:

The lower minimum voltage could mean those of us with power based limits will have to assume 207v ie 3.3kw rather than being able to set 3.6 or even 3.9kw.

 

Would expect you to use the nominal voltage for these calculations. ie, 240V. Up to the network to be designed for the variance.

[-rick-]

Also, just thinking about the situation you'd be in if the voltage was 207V. It would mean that the local substation is under very heavy load from a local consumer and near tripping off. Therefore, the extra current produced by your inverter at that voltage might be the thing that prevents the grid from tripping.

 

An argument may be that the current limit protects the cables, but I would guess that it's the substation transformer that is the limiting factor in almost all locations. In fact the areas where you may see voltage dipping to near 207 are likely all rural with pole transformers and long lines. Likely meaning that a generator closer to the consumer may reduce the voltage drop in the lines and be even more beneficial.