Solar PV

[steptoe]

just had NICEIC out today for accreditation,

he seems happy with what I have done so far, even offered a few tips as to how to get away with running a smaller cable back to main DB.

voltage drop requires a 4mm, but efficiency levels require 6mm minimum,

going to install a 1way board beside inverter and then can get away with 4mm back to main DB.

rainydays:

DC isolator required at inverter, and AC isolator required at inverter and DB/CU if inverter not at same location,(DC cables need to be kept as short as practicable), also requires DC isolator at array if danger could arise from DC cables remaining energised from PV.

lots of reading, so if anyone needs any links I'll get some sorted as soon as I get finished this project.

will be ready for power up tomorrow hopefully(fingers crossed),

didnt have time today to get pics due to taking NIC man round other sites to look at heat pump and solar thermal.

 

[Lee321]

sounds goooood

 

[Manator]

Yes it does sound good, any more pics would be welcome and thanks for the very useful information thus far.

 

[binky]

Out of interest is there a requirement to prevent backfeed to mains should mains supply fail???? Could imagine DNO guys getting belted otherwise.

 

[Lee321]

it would trip the mcb binky as the load would be so great

 

[steptoe]

Out of interest is there a requirement to prevent backfeed to mains should mains supply fail???? Could imagine DNO guys getting belted otherwise.

yes there is,

our inverter has this built in apparently,

as do (as far as I can ascertain) all standard MCS accredited inverters.

some of the BUMF really overcomplicates stuff, and seems that really if its MCS certified then its not so complicated,

now that Ive almost sorted this one I'll sort out links(as promised) as to what is relevant and what is total bumf.

NIC back on thursday to finalise accreditation.

oh, and as someone else mentioned(sorry forget who), Im booked in for a course on these too, it is a requirement as well as the practical.

more pics tomorrow, will deffo get time.

inverter mounted today, and conduit placed in ,

biggest issue I have had so far(apart from the boss) is design/planning, actual installation isnt that difficult.

you just have to be wary about having 230v DC floating around!

and TBH, once you have one designed, then its very similar except about actual positions of stuff from there on in.

BTW, this is a simple 16a install, anything above that is more complicated.!!!!!

but Ive had to trawl through all that info too just to find the bits I needed.! headbang

 

[steptoe]

it would trip the mcb binky as the load would be so great

not necessarily, it really is a lot different to normal supply,

remember you are now supplying on the LOAD side of the MCB in parrallell, and you are now introducing an extra fault path should you only have single pole protective devices, ie, SP RCBOs.

 

[binky]

So how do you stop yourself getting belted from the panels ?? Plastic bin liners??, raybans???

 

[steptoe]

So how do you stop yourself getting belted from the panels ?? Plastic bin liners??, raybans???

there is NO method of doing this, except via design,

the panels I am using supply 38.?v per panel, 6 in series produce 230v ish, if you really need to know I'll get specific info,

this is one reason I fit isolators beside the array, to isolate the cables from 230v DC.

remember, DC will pull you in, NOT throw you off as AC will,

also the isolators are much higher rated, AC isolators are NOT permitted on DC side,

AC hits 0v 50 times each second, so much less load to disconnect, DC is ALWAYS at 230v so much greater load,

one way round this is to use(as I have done) 3ph isolaters linked as they are designed for 230v at any point in the wave, ie, 230v permanently, NICEIC seem happy enough with this solution.

 

[Sidewinder]

I guess you can switch out individual panels then?

Never done PV yet. Had an interview to work on PV design & manufacture (staff engineering post) at a manuf' facility about 15 years ago, (ish) never got the job, not enough experience in the field at the time!

 

[steptoe]

I guess you can switch out individual panels then?Never done PV yet. Had an interview to work on PV design & manufacture (staff engineering post) at a manuf' facility about 15 years ago, (ish) never got the job, not enough experience in the field at the time!

no, not unless you design includes a variable transformer,

the plant Im doing ATM doesnt include a transformer, only an inverter,

whatever it gets in DC it changes to AC, so it requires 230v DC in to give 230v AC out.

the only purpose of my isolator at the array is to isolate the actual cables and make them safe to work on,

as I said, DC is inherently MUCH MUCH more dangerous than AC.

anyone here ever got a dig from their car HT leads?

if that was AC it would have been a mere fraction of the time and therefore so much less.

 

[Sidewinder]

Oh yesssss I've had a few kV's from cars in my time!

 

[Sidewinder]

BTW i have had a belt of 800V d.c. from an industrial motor drive on test when we were doing repair training, that hurt!

 

[steptoe]

BTW i have had a belt of 800V d.c. from an industrial motor drive on test when we were doing repair training, that hurt!

THATS BIG!

well solar PV should never be that big if designed correctly,

as I said, the design is/has been my big headache,

now I have that done the rest doesnt seem so bad.

once the DC side is done, its all about efficiency on the AC side, that takes precedence over volt drop, if efficiency is OK the in all probability volt drop will be fine by the calcs I have done anyhow.

anyway, once I get this all over with I will do something for the tips section that will hopefully help all others going for the same thing, ie, MCS ,

maybe admin or some other respected members will be able to help me sort out proper links for my info as I get it sorted.

 

[Sidewinder]

We had some installed with hold up caps too seen the end blown off a screwdriver by one guy not willing to wait to replace one and that was with a 300V d.c. bus!

We tried to design for the highest d.c bus voltage to get the best efficiencies and torque outputs of the pm motors.

 

[kme]

May be able to provide some insight shortly - going to be doing MCS accredition under the umbrella of the supplying company; to be their installer of these systems.

Send us a PM when you`ve got a min, Albert - I`m not here a heck of a lot at the mo; but I AM here

 

[steptoe]

all fired up and working.

going to do a MCS 3day course on monday.

DC isolator to the left.

 

[Lee321]

on new jobs if they omit the normal roofing type i.e tiles or corrugated etc it will make the install of pvc more effective.

new goverment buildings should be installing these as alternative roof types by default

looks good steps

what puts people off installing domestic is the 8 years before a return although house value will be higher its hard to see that effect

 

[green-hornet]

Looks good, and thanks for the step by step guide very interesting.

 

[steptoe]

on new jobs if they omit the normal roofing type i.e tiles or corrugated etc it will make the install of pvc more effective.new goverment buildings should be installing these as alternative roof types by default

looks good steps

what puts people off installing domestic is the 8 years before a return although house value will be higher its hard to see that effect

with this system they reckon 5 years return,

I'll try get some prices dug up.