Author Topic: Dynamic demand project(s)  (Read 14130 times)

0 Members and 1 Guest are viewing this topic.

DamonHD

  • Administrator
  • Super Hero Member Plus
  • *****
  • Posts: 4125
  • Country: gb
    • Earth Notes
Dynamic demand project(s)
« on: July 03, 2013, 03:57:58 PM »
Right, I've started *another* project (I have too many going):

https://sourceforge.net/projects/dhddd/

The aim is to build prototypes that will make individual houses/appliances more grid-friendly by reducing instantaneous power demand when (a) grid frequency drops and/or (b) the house is not exporting from local grid-tied microgeneration.

This should basically help make the house import less from the grid especially when the grid is stressed.

But this could also help with big off-grid systems by avoiding them tripping if too much load goes on at once and/or the microgen drops, eg the sun briefly goes behind a cloud.

In particular I want first to try with an ordinary electric (tea)kettle, then may also try with my dishwasher.

I may build it with PICAXE or AVR/Arduino for the microcontroller element, and it'll have a radio module, transformer for power (and crude voltage/phase sensing with current clamp at consumer unit), and meaty zero-crossing SSR for appliance control.

Nothing to see yet, but a great chunk of the design will be cut-n-paste from elsewhere!

Rgds

Damon
Podcast: https://www.earth.org.uk/SECTION_podcast.html

@DamonHD@mastodon.social

SparWeb

  • Global Moderator
  • Super Hero Member Plus
  • *****
  • Posts: 5452
  • Country: ca
    • Wind Turbine Project Field Notes
Re: Dynamic demand project(s)
« Reply #1 on: July 04, 2013, 12:15:50 AM »
Frequency-dependent load shedding?  Cool idea.  Stop giving them away before you start the patent applications.

What's wrong with another project?  If you double the number projects that you say you have, and I stop half of the projects I've recently started, then I'd still have twice as many as you.

So assuming a +/-1Hz hysteresis: monitor frequency, and if at 50 Hz act normally, if below, say 49Hz, stop the discretionary things, if above 51Hz then start those things that have been delayed.

Are you sure the grid frequency is a suitable measure?  It sounds good on the surface, but my reflex is to think of the coal-fired steam turbines slowing down as the city's load goes up.  In a micro-grid situation it might be different. 

No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
System spec: 135w BP multicrystalline panels, Xantrex C40, DIY 10ft (3m) diameter wind turbine, Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024
www.sparweb.ca

DamonHD

  • Administrator
  • Super Hero Member Plus
  • *****
  • Posts: 4125
  • Country: gb
    • Earth Notes
Re: Dynamic demand project(s)
« Reply #2 on: July 04, 2013, 01:16:27 PM »
Hi,

I have a bunch of data that says grid frequency is a good measure of some types of urgent trouble, and this is already used as a signal for automatic load shedding (to the tune of ~2GW in the GB I think).

But the tolerances are tighter than +/- 1Hz:

Quote
An analysis of figures supplied by National Grid for August 2008 (.xls) (a frequency sample every minute for the entire month) indicates only one sample out of nearly 45,000 potentially below the operational -0.2Hz target, but ~3% at or below -0.1Hz (ie frequency ≤49.9Hz) and ~17% at or below -0.05Hz (ie frequency ≤49.95Hz).

Thus if dynamic demand control in domestic appliances is to be of help with (and reduce the cost of) 'balancing' of today's UK grid, it would have to start to intervene before the -0.2Hz operational limit. Somewhere between one half and one quarter of that limit looks plausible, especially if the response can be graded and smoothed, where it will help a small proportion of the time but with the current/normal grid mechanisms doing the fine tuning.

http://www.earth.org.uk/note-on-dynamic-demand-value.html#when

Already a patent minefield I'm sure, but the balancing with local PV microgeneration may be useful a much higher fraction of the time, and the randomised part of it should help to ensure that the local substation sees a fairly smoothly-reduced load from a number of houses/appliances downstream of it using the technology.

Anyhow, all idle talk until I do it.  May make up a generic design and PCB first to put off having to think too hard for another fortnight!

Rgds

Damon
Podcast: https://www.earth.org.uk/SECTION_podcast.html

@DamonHD@mastodon.social

Larsmartinxt

  • Newbie
  • *
  • Posts: 48
  • Country: no
Re: Dynamic demand project(s)
« Reply #3 on: July 04, 2013, 07:38:08 PM »
Interesting Project.
I'm sure that you've found this http://www.mainsfrequency.com/

DamonHD

  • Administrator
  • Super Hero Member Plus
  • *****
  • Posts: 4125
  • Country: gb
    • Earth Notes
Re: Dynamic demand project(s)
« Reply #4 on: July 05, 2013, 03:01:50 AM »
Yes, not our bit of the grid, but talking about the same thing.

Rgds

Damon
Podcast: https://www.earth.org.uk/SECTION_podcast.html

@DamonHD@mastodon.social

Larsmartinxt

  • Newbie
  • *
  • Posts: 48
  • Country: no
Re: Dynamic demand project(s)
« Reply #5 on: July 05, 2013, 09:28:37 AM »
Do you have a graph or other visual data on the frequency of the UK grid? Asking because I'm interested in how stiff the UK grid (Thermal power) are compared to the Norwegian (Hydro)

SparWeb

  • Global Moderator
  • Super Hero Member Plus
  • *****
  • Posts: 5452
  • Country: ca
    • Wind Turbine Project Field Notes
Re: Dynamic demand project(s)
« Reply #6 on: July 06, 2013, 12:56:58 AM »
There's a lot of talk about appliances that automatically shut themselves down or activate themselves when a signal from the grid indicates to do so.  Many people (myself among them) object to that because I loose my power to choose.  I've heard the argument that the grid can be more efficient if the loads are managed more efficiently, but I selfishly want my clothes dry in the morning too.  If it is implemented (my jurisdiction is just one legal step away from it) it will lead to a lot of jury-rigging of new household equipment.  Another thing that's already happening in some other jurisdictions is the time-of-use billing, not here yet.  Also an attempt to modify behaviour, this time using cost.

What you are working on is similar, but instead here is a way for people to actually have some control over the process.  A sense of control for those who care, and an automatic device for those who don't.  That sense of agency combines well with knowing that you are reducing grid peak loads, hence reducing emissions on the least efficient part of the scale, and transmission losses, too.

No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
System spec: 135w BP multicrystalline panels, Xantrex C40, DIY 10ft (3m) diameter wind turbine, Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024
www.sparweb.ca

Mary B

  • Administrator
  • SuperHero Member
  • *****
  • Posts: 3169
Re: Dynamic demand project(s)
« Reply #7 on: July 06, 2013, 01:34:20 PM »
Utility managed load shedding will lead to a high demand for retro appliances without the electronics.... I sense a new business opportunity!

frackers

  • Sr. Member
  • ****
  • Posts: 435
  • Country: nz
  • Picard spits "Hello"
Re: Dynamic demand project(s)
« Reply #8 on: July 06, 2013, 09:13:34 PM »
There's a lot of talk about appliances that automatically shut themselves down or activate themselves when a signal from the grid indicates to do so.  Many people (myself among them) object to that because I loose my power to choose.  I've heard the argument that the grid can be more efficient if the loads are managed more efficiently, but I selfishly want my clothes dry in the morning too.

We use 'ripple control' a lot here in NZ - the local lines company has a pdf that describes it here http://www.oriongroup.co.nz/downloads/RippleSignalGuide.pdf

Our home system has 2 circuits - one for hot water and the other for day/night charging control (handy to know that I can irrigate on cheaper power!!).

Not sure what the implications will be when I get my 6kw of grid tie finished :)

Robin Down Under (Or Are You Up Over)

DamonHD

  • Administrator
  • Super Hero Member Plus
  • *****
  • Posts: 4125
  • Country: gb
    • Earth Notes
Re: Dynamic demand project(s)
« Reply #9 on: July 07, 2013, 09:00:00 AM »
@Larsmartinxt

1) There is no "UK" grid: the grid in Northern Ireland and the Republic is managed together, and separate from the GB grid.

2) Here's a lovely set of data for the GB grid:

http://www.bmreports.com/bsp/bsp_home.htm

Rgds

Damon

PS It is possible to get at the last few years' worth of data historically which I think includes frequency, I haven't actually looked.
Podcast: https://www.earth.org.uk/SECTION_podcast.html

@DamonHD@mastodon.social

DamonHD

  • Administrator
  • Super Hero Member Plus
  • *****
  • Posts: 4125
  • Country: gb
    • Earth Notes
Re: Dynamic demand project(s)
« Reply #10 on: July 22, 2013, 12:04:50 PM »
Slow progress.  I at least have a Web page up for it now:

http://www.earth.org.uk/domestic-dynamic-demand-ideas.html

I think I have the voltage monitoring part sorted in my head, but still need to understand the current loop better...  May get to update the schematic later today...

Rgds

Damon
Podcast: https://www.earth.org.uk/SECTION_podcast.html

@DamonHD@mastodon.social

DamonHD

  • Administrator
  • Super Hero Member Plus
  • *****
  • Posts: 4125
  • Country: gb
    • Earth Notes
Re: Dynamic demand project(s)
« Reply #11 on: August 04, 2013, 11:47:17 AM »
Think I have the schematic done...  (Normally I'd breadboard and actually have some code tested at this point, but never mind.)  Bo in Denmark is slaving over the PCB with the hope of shipping the PCB design to China tonight and a component order to RS also...

Also, a 3D printer (the Velleman K8200) has been ordered to assist with at least making safe/custom cases for this and OpenTRV...

Rgds

Damon
Podcast: https://www.earth.org.uk/SECTION_podcast.html

@DamonHD@mastodon.social

DamonHD

  • Administrator
  • Super Hero Member Plus
  • *****
  • Posts: 4125
  • Country: gb
    • Earth Notes
Re: Dynamic demand project(s)
« Reply #12 on: August 31, 2013, 12:31:44 PM »
Hi,

A couple of hours ago I started assembling the first board.

I wish I'd started on SMD *before* my eyes started to go bad!

I've done a fair chunk of the board, and have added tweezers and a magnifying glass/stand to my toolbox today.

Rgds

Damon

PS. Hope to actually write some code for this thing this weekend also...

PPS. Finished assembly of first board: http://gallery.hd.org/_c/energy-matters/_more2013/_more08/DD1-prototype-201308-schematic-and-PCB-REV0-from-screen-to-hand-soldering-assembly-of-dynamic-demand-demand-smearing-random-half-cycle-dropper-27-DHD.jpg.html and http://gallery.hd.org/_c/energy-matters/_more2013/_more08/DD1-prototype-201308-schematic-and-PCB-REV0-from-screen-to-hand-soldering-assembly-of-dynamic-demand-demand-smearing-random-half-cycle-dropper-29-DHD.jpg.html
« Last Edit: September 01, 2013, 12:29:04 PM by DamonHD »
Podcast: https://www.earth.org.uk/SECTION_podcast.html

@DamonHD@mastodon.social

Bruce S

  • Administrator
  • Super Hero Member Plus
  • *****
  • Posts: 5370
  • Country: us
  • USA
Re: Dynamic demand project(s)
« Reply #13 on: September 06, 2013, 09:54:51 AM »
I've found the ones with the LED light to be quite helpful. I did replace the clunky alligator clips with forceps though. Smaller footprint on board I'm already having problems seeing  ;).
Cheers;
Bruce S
A kind word often goes unsaid BUT never goes unheard

DamonHD

  • Administrator
  • Super Hero Member Plus
  • *****
  • Posts: 4125
  • Country: gb
    • Earth Notes
Re: Dynamic demand project(s)
« Reply #14 on: October 01, 2013, 01:58:40 PM »
I'm in the semi-finals now!

Rgds

Damon
Podcast: https://www.earth.org.uk/SECTION_podcast.html

@DamonHD@mastodon.social

DamonHD

  • Administrator
  • Super Hero Member Plus
  • *****
  • Posts: 4125
  • Country: gb
    • Earth Notes
Re: Dynamic demand project(s)
« Reply #15 on: October 20, 2013, 05:42:40 AM »
The Hackathon finished yesterday and we didn't progress to the next round, but we had a lot of fun and sharpened up one possible product idea!

Rgds

Damon
Podcast: https://www.earth.org.uk/SECTION_podcast.html

@DamonHD@mastodon.social

DamonHD

  • Administrator
  • Super Hero Member Plus
  • *****
  • Posts: 4125
  • Country: gb
    • Earth Notes
Re: Dynamic demand project(s)
« Reply #16 on: June 29, 2014, 09:39:28 AM »
Went to the presentation of the final award (GBP50k) on Thursday and did some networking!

Rgds

Damon
Podcast: https://www.earth.org.uk/SECTION_podcast.html

@DamonHD@mastodon.social