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Author Topic: Grid Hopping  (Read 61048 times)
jonesy
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« Reply #45 on: September 12, 2015, 03:12:35 PM »

Something that occurred to me overnight.  There is a method to program a pic through the serial port - it's called serial bootloading.  It is technically possible on the '877a; the person that wrote the code would have needed to put a special extra bit in.  IIRC Microchip have provided bootloader add-ons.  You would need to know the protocol of the bootloader, so maybe some more googling required.  Do you have the windows programme and software update file you could link me too.  I might be able to work out how to put the updated code in.
However, you'd still need to identify pins that a programmer/bootloader could connect to.
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Scruff
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« Reply #46 on: September 13, 2015, 06:03:37 PM »

Interesting Paul  thx. bike

Jonesy, Thanks for the offer. Much appreciated. It's on the back burner for now. I'm outta port for a month and the mass combi is the other side of the water. If I tackle it again I'll love some help. I shy away from speaking to them spidery silicon things.

According to investigations and iirc:

The RJ11 has:
Ground common to battery 0VDC and isolated from the chassis.
Rx goes through a 1kΩ resistor to pin 44
Tx goes through a 1kΩ resistor to pin 1
                                              that's what I meant by inverted... Huh faint

Vcc goes to two diodes  I think, (maybe...they look like SMD diodes, I didn't probe them for Vf) maybe halfwave, then disappears through to the other side of the board which, for now, is a screwdriver no fly zone and doesn't appear to re-emerge at the PIC which is conformally coated.
My TriStar can see the Edgeport but my DVM is only reading mV from the DB9 out.


Priorities:

There's been some plumbing rearrangements










I'll post larger pics if the internet on this hillside improves.


If Conductor CSA isn't indicated it's per pair DC or per multi core.
Naughty centre tap on the batteries to run a SmartGauge for Mrs Scruff to understand.
Spare Programmable Alarm contacts on the Smartgauge.  Smiley
« Last Edit: October 20, 2015, 12:50:21 AM by Scruff » Logged
jonesy
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« Reply #47 on: September 13, 2015, 10:15:42 PM »

2500kVA eh?  Might get one myself at that price Grin
The neutral earthing through a relay is interesting - boat specific? I've no experience there. I like their 'local rules may apply' get out of jail free card.
Isnt the neutral/earth relay a point of failure as there is no way of knowing that it has made the link, or burnt out - it isn't fail safe.
The pin numbers I gave for the 877 are the DIL version.  Is yours surface mount?
Not so long ago I came across a mass produced British made product that used a mini USB socket.  If you connected it to your laptop, it blew out the USB, as it was actually rs232 levels.  Is the 9D rs232?
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camillitech
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« Reply #48 on: September 13, 2015, 11:03:04 PM »


The neutral earthing through a relay is interesting - boat specific? I've no experience there. I like their 'local rules may apply' get out of jail free card.
Isnt the neutral/earth relay a point of failure as there is no way of knowing that it has made the link, or burnt out - it isn't fail safe.


Aye Jonesy, this is common and accepted practice regarding connecting boats to a shore supply. Like you rightly point out 'it isn't fail safe' on most small craft but an alarm will activate on larger vessels.
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'Off grid' since 1985,  Proven 2.5kW, Proven 6kW direct heating, SI6.OH, 800ah Rolls, 4.75kW PV ,4xTS45, Lister HR2 12kW, , Powerspout pelton, Stream Engine turgo, 60 x Navitron toobs and a 1500lt store. Outback VFX3048 and 950ah forklifts for backup,
Scruff
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« Reply #49 on: September 13, 2015, 11:26:04 PM »


The neutral earthing through a relay is interesting - boat specific? I've no experience there. I like their 'local rules may apply' get out of jail free card.
Isnt the neutral/earth relay a point of failure as there is no way of knowing that it has made the link, or burnt out - it isn't fail safe.


Yeah it's a boat thing along with the lightweight = better than surge capacity.
It's because steel hulls have issue with earth leakage galvanically digging holes in the hull and RF interference. Hence they carry isolation transformers and don't want a hard link.
It's also a throughput on the same terminals, It automatically diverts grid to output in the presence of mains.

I don't like it in a house. I'm wondering if a neon in parallel with load neutral and earth might give me a continuity alert. It'll give me less overhead on a 30mA RCD if it works. Any thoughts? Trust the engineers?
I didn't notice a fault indicator for "hardware error earth leakage protections disabled".... Undecided


The pin numbers I gave for the 877 are the DIL version.  Is yours surface mount?

Yurp SMD,
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jonesy
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« Reply #50 on: September 15, 2015, 11:59:58 AM »

I don't like it in a house. I'm wondering if a neon in parallel with load neutral and earth might give me a continuity alert. It'll give me less overhead on a 30mA RCD if it works. Any thoughts? Trust the engineers?
A couple of things occur to me. 1. do mastervolt do a home version.  An email may get you some advice 2. whilst switched earthing is accepted for boats, is it at home?  If the inverter didn't have the charger and built in bypass, life would be a lot easier.  I'm kind of at a loss, as anything you try to do on the output will reflect to the input when the inverter is not running. The neon will show the relay not operating, and the leakage is trivial. Void the warranty, remove the bypass and link?

As for the PIC, if it's 44 pin, but not socketed, pin 1 is receive, pin 44 is transmit.  Both pins should be at +5, but sloppy designers don't put a pull up on the RX. If that is a dedicated programming port, they will be doing a bootstrap of some sort.  It's also possible they are just messin with you, as the pins can be re-assigned as general IO, in which case I don't rate your chances of hacking a programmer, but send me the info when you're ready.  I like a challenge.

For a transformerless inverter, should you be installing a type B RCD, which protects the installation against DC locking out a A or AC RCD.  The inverter may already have such protection built it (SMA GTIs do).
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Scruff
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« Reply #51 on: September 15, 2015, 11:57:15 PM »


A couple of things occur to me. 1. do mastervolt do a home version.  An email may get you some advice 2. whilst switched earthing is accepted for boats, is it at home?  If the inverter didn't have the charger and built in bypass, life would be a lot easier.  I'm kind of at a loss, as anything you try to do on the output will reflect to the input when the inverter is not running. The neon will show the relay not operating, and the leakage is trivial. Void the warranty, remove the bypass and link?

Yeah emailing Mastervolt would be an idea alright.
Easiest thing to do is loose a very efficient 30A charger. Not connect the mains feed to it and hard tie the inverter N & E at the terminals.
I've already voided the warranty twice.  Grin


This is an interesting page of Blue Box Plus manual.



but send me the info when you're ready.  I like a challenge.

Will do.  genuflect


For a transformerless inverter, should you be installing a type B RCD, which protects the installation against DC locking out a A or AC RCD.  The inverter may already have such protection built it (SMA GTIs do).

There's at least 6 transformers in my gizmo gadget...please explain...I like the sound of those RCDs already.

Pic of trunking porn for Biff

« Last Edit: September 16, 2015, 12:40:14 AM by Scruff » Logged
jonesy
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« Reply #52 on: September 16, 2015, 11:19:31 AM »

Well, I looked at the manual and the default NE relay setting is off.  I suppose you could install another transfer relay before your own transfer relay and put the NE link there.
The RCD thing is to do with how RCDs operate.  The AC/A type use a coil with L & N threaded through and any current difference will be detected by another winding. If your high frequency/transformerless inverter puts a bit of DC onto the AC supply, which can be under normal operation, this DC interferes with the RCD coil and generally they won't trip if they detect an AC fault. A type B RCD typically has a hall effect device to detect/ignore the DC and will carry on working ok. Manufacturers of HF inverters try, by design, to prevent DC appearing on the AC terminals.  SMA  do this (it's in the manual IIRC), so a normal type A/AC RCD is fine.  I've never looked, but I'd think type B are bit pricey, just like 100mA time delay for TT systems. I did a word search for RCD in the mastervolt manual, but they don't give guidance on the RCD.  Probably worth an email.
The 6 odd transformers you have will probably be HF converting the 48V to 400V, amongst other things.
I had a squint at the rs232 and re-read your post.  You need to connect the 0v/Vcc on the max chip, otherwise it won't work.  The easiest way to test the max232 is as I posted before.  Give it some juice, plug into the pc, and link the rx/tx that would have gone to the mastervolt.  Find the com port on the pc (device manager) and use realterm or putty to open a rs232 session on that port.  Type a bit and the characters should appear on the screen.  Remove the link and the characters stop.  Job done, close realterm and plug into the mastervolt and use their software. If their software can't detect the inverter, swap tx/rx on the inverter.
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Nickel2
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Method mixed with Madness


« Reply #53 on: September 16, 2015, 01:27:25 PM »

Hi Jonesy.
 Purely as a matter of curiosity; I know RCDs rely on a L/N current balance/imbalance to trip, how does injected/unwanted DC stop them working properly? I can understand that a wave-shape difference between the positive half of the waveform and the negative half could cause a residual DC effect, but would that be enough to cause a problem? Core saturation or something like that?
 Smiley The more I know, the happier I am! Smiley
N2
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EpEver 4210A at 24v
24V 400 Ah battery. (4x200Ah FLA)
EpEver STI1000-24-230 pure sine inverter
Of course it'll work. (It hasn't caught fire yet).
jonesy
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« Reply #54 on: September 16, 2015, 04:15:06 PM »

Yes. Saturation.  There is a nice description here http://www.theiet.org/forums/forum/messageview.cfm?catid=205&threadid=59058 , copied below
ALL RCDs will trip with a normal resistive fault between L and E, but the more common ones use a current transfomer, which can become magnetically saturated and locked out if there is DC present.
So a fault in a system with rectifiers with a fault between the wiring after the rectifier and ground, may inject only a single sided fault current, and as real transformers don't do DC, the fault will not cause a trip if is a well smoothed DC, and the fault came on gently, and worse, this DC may also saturate the iron core, and reduce sensitivity or even prevent it responding at all to a normal fault.

So now, to combat this we add a hall effect sensor to the design, instead of the secondary winding of the current transformer core, now the trip can be made to respond to any uni-polar magnetisation of the core in the RCD, as well as just changing 50Hz component. Then there are various degrees of either friskiness or delay to the responses of the DC and AC parts to accomodate high frequency pulses, and either ignore or respond to switching transients as desired.

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Nickel2
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« Reply #55 on: September 16, 2015, 07:29:41 PM »

Cheers Jonesy, more Nollij.
I had never really considered a DC component in an AC imbalance trip.
Article read and understood, ta. (scratches head and tries to remember 40 years ago college stuff on magnetism. Exams passed, stuff forgotten.)
N2.
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1.140kW mono south-facing at 49*
EpEver 4210A at 24v
24V 400 Ah battery. (4x200Ah FLA)
EpEver STI1000-24-230 pure sine inverter
Of course it'll work. (It hasn't caught fire yet).
Scruff
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« Reply #56 on: September 28, 2015, 05:18:25 PM »

Prompt reply from Mastervolt;

Dear Mr ....,

If you use a Mass Combi 48/2500-35 and you want to install an RCD on the shortbreak output you should not make a fixed connection between N and PE.

In the Mass Combi we provide and ground relay which makes the connection between N and PE when the unit is operating as an Inverter. The relay coil is energized when the unit is in inverter operation.

It is an electro mechanical relay and we never had any failure on these relays.

If you activate the GND relay in the Mass Combi (dipswitch row A no 8 ) you will have a connection between N and PE in inverter operation. This will make the RCD work when on inverter operation. When the Mass Combi is powered by AC mains this connection is open as then the RCD before the Mass Combi will act as a safety.

There is no fault indication when the Ground relay is not functioning.

If you want an indication if the ground relay is actiavted or not you can use a small neon light connected between PE and N. If the ground relay is activated the neon light will be off when the combi acts as an inverter.

We hope this answers your questions. If you have more questions feel free to contact us.


Best regards,
....
« Last Edit: September 28, 2015, 05:20:11 PM by Scruff » Logged
jonesy
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« Reply #57 on: September 29, 2015, 09:56:02 AM »

...if you want to install an RCD on the shortbreak output you should not make a fixed connection between N and PE
Well, that's correct, as a fixed link at the output would/could change the shore earthing scheme. As PME isn't permitted to supply a boat, you'd be creating a dangerous situation and in any event, IIRC PME only permits E & N link at the supply/source.

The house is always earthed, so the main risk if the NE relay link fails to make on inverter supply is that the output side RCD fails to operate under fault. ie you want TN-C-S (PME), but the system degrades to (floating) IT without warning. RCDs can fail to operate correctly without a path to earth. A RCD is inadequate to protect IT systems.
I experienced something close to this when I was on a TT supply. It was a hot summer & I lived on granite, about 200m from the supply transformer.  The leccy board had replaced some overhead lines. The day after I was installing a new socket when I realised N was live WRT earth. I rang and suggested they had a problem. They were there in minutes and confirmed the fault. L & N had been reversed. Then the guy decided to trip my incomer. The supply L became live again. A check showed I had a full L/E fault, but the RCD didn't trip as there was no earth path ie there was no earth return through my earth rod to the transformer due to the dry conditions, basically giving me an IT system. The L/E fault was swarf on a pattress box screw head piercing the L insulation.
You'll need to draw this out to check it, and ask mastervolt another question.  You must state you are in a house! If you link the incoming and outgoing N and disable the NE relay, that will mean the house earthing scheme is reflected to the inverter side?  I'm pretty sure that's what APC do.
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Scruff
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« Reply #58 on: April 29, 2016, 06:01:44 PM »

I keep thinking Jonesy an earth loop impedance check ought to have flagged that? Shouldn't that be conducted between supply and electrode before commissioning, or did they just wait for a wet day to test it?

So I dropped the ball on this thread. I'll probably do that a few times before I'm done.  tumble
It's happening slowly..here's the reason for my predicament.



Lead tie inverter manual versus grid tie inverter manual.

..'cept it's only the inverse square of that predicament because they're multilingual manuals.  ralph

The latest plumbing draft. [.pdf attached end of post is clearer]


Story so far, there's a 12volt battery on a 110W module powering a 12VDC outlet, Usbs, isolated meter power it's own meters and led lighting in the power plant on a ProStar 30 through LVD. There's a 12kWh battery that holds 12.85V (current available charger friendly configuration) for 3 month's unassisted chillin' out, a TriStar 45 PWM sitting on a wall being a boss and not connected. A Mass Combi 2.5kVA having a rest, 10kg of switchgear and sundries, ~ 900Wp of GM's poorly, cracked not fractured amorphous modules awaiting physiotherapy (thx  Wink), 110m of assorted cable on reels. Meters on the meters and latest addition to the family a 550W grid tie rig.

There's a back order on conduit, consumables, cabinets, cases, gubbins, more cable, better wiring practice examples and the where-with-alls to plumb it. Plans for earthing yet undecided.

Here's my new to me 500W panel on the examination table.



3 year old modules gorsh  whistlie better uprate them to 550Wp  Grin


Left meter is Soladin output right is power from the panels.
580W is the best lense I sawr.  faint



There were reasons this was best...I'm not sure I've convinced myself though by having done it...maybe time will tell...

Sadly I lose all harvest before 11am from this mount. 15 West.

The meter shown is affectionately known as cr@p meter.



It is an Ah counter, completely useless as such between a panel and a grid tie inverter. A Wh counter would have accuracy.
It's a nightmare to calibrate and so far close enough is the best I've done in 3 days fighting (this is a zero reading). The best thing to do when you get it is look at the instructions once..get the gist, then burn them because they lead one up the garden path. I only have this as an accidental order, mistaken for it's twin the battery SOC meter, which is also a nightmare to calibrate with misleading instructions but not as cr@p. Anyways it does Watts ok so I can see the efishinseas (efficiencies? ...no? tumble).
The Ah meter shunt is hanging out in the PV panel isolator enclosure.

That Soladin has a noisy ineffectual little blighter of a fan...putting a better one that small in there won't achieve much....  I paralleled a 120mm low RPM computer case fan (0.5W) mounted it on 1" stand-offs and ducted draft from the upper Soladin vent to away..works great, real quite now, Soladin doesn't seem stressed....well in this weather.



I don't know what's to become of this system. At the moment it's singing for it's supper so happy to keep it. My 48V might assimilate the panels in parallel 50Vmp. The Soladin might take a break. Or maybe it's MPPTness earns it a place and maybe that place is a mass combi-genset support mode (except they're both anti-islanding... Undecided). Maybe stand alone.
 


* 48V grid hopping MK II.pdf (132.1 KB - downloaded 110 times.)
« Last Edit: April 30, 2016, 08:36:37 AM by Scruff » Logged
Nickel2
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« Reply #59 on: April 29, 2016, 06:47:26 PM »

Your 'Ah' meter sounds like a register of disappointment, as in - (looks at solar production) 'Ah'... Grin
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1.140kW mono south-facing at 49*
EpEver 4210A at 24v
24V 400 Ah battery. (4x200Ah FLA)
EpEver STI1000-24-230 pure sine inverter
Of course it'll work. (It hasn't caught fire yet).
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