energy monitor suitable for three phase

[camillitech]

Hi Guys,

I'm looking for an energy monitor that I can use to monitor the output from my hydro turbine that will produce a graph on my computer. There seem to be plenty out there but would they be suitable for a 230v three phase supply 

Cheers, Paul

[A.L.]

hello paul,

I believe that current-cost meters with two additional clamps can monitor three phase but they combine outputs into one.

[skyewright]

I believe that current-cost meters with two additional clamps can monitor three phase but they combine outputs into one.

The standard CurrentCost CC128 transmitter has 1 fixed clamp, and can take 2 extra clamps (around a tenner each IIRC?).

I have a couple of those units. I use them to monitor the separate sections of our "Total Heating Total Control" consumer unit rather than for 3 phase, but I presume the general idea is the same.

The CC128 console shows the 3 clamps as one value, but if you pull the data out and analyse it with other software the individual values are available. The data format is well documented and straight forward (its xml).

Something I have found in practice is that significant power (say 1kW or more?) through one of the clamps causes a small "phantom" load to be reported by other clamps on the same transmitter unit, e.g. if our storage heaters are on, the water heater circuit registers a small load even though it is off. However the whole system only gives an approximation anyway, so that may not be a big deal for you (it isn't for me). If you want to avoid the issue then you can get other transmitters that only have one clamp each, and I assume that they don't suffer from the interference problem (I've never seen interference between my two 3 clamp units).

[camillitech]

Thanks AL, Skyewright,

would it be possible then just to multiply the reading from one meter by three, or is it divide 

Cheers, Paul

[Fintray]

Paul

I would have thought that it would be ok to just take one clamp and multiply the reading by three?
This may be complete tosh and there could be other factors I am missing!

[guydewdney]

The CC reads all three with the additional clamps - I have one. The aftermarket software can show each of the three phases. Its not necessarily balanced, as each phase may have different loads on it (eg lighting).

Guy

[roscoe]

If want any degree of accuracy I would look into getting a cheap/budget/refurbished/secondhand 3 phase meter, rather than the CC or similiar units.
Lot's of places to find them,....
 http://universalmeterservices.co.uk/store/index.php?main_page=index&cPath=4

If you want to log the kwh, then some pulsed interface would probably be a low cost way to do it
A great application for the ethernet arduino at £12.50, plus opto-coupler maybe ?

[camillitech]

Thanks chaps,

Guy, it's for my 'Stream Engine' and all the inputs go into the transformer so are (I assume) balanced, anyway I wasn't after super accuracy more something that would provide a graph on a computer that I can monitor over the year.

Roscoe, I already have that very meter in my system but cooked it on start up when I was playing about with nozzles off load  and the voltage went way over 440  . Though I'm going to get another 

I'm not the brightest when it comes to leccy and puters but as I've already been monitoring rainfall for 10 months I'm hoping to build up some useful picture of rain/time of year/water flow and power output. Any suggestions would be most welcome 

Cheers, Paul

[skyewright]

Guy, it's for my 'Stream Engine' and all the inputs go into the transformer so are (I assume) balanced, anyway I wasn't after super accuracy more something that would provide a graph on a computer that I can monitor over the year.

In that case a CC128 (or some such) should be fine. The figures won't be 100% accurate, but I'd guess that in your sort of situation they ought to at least be consistently so?

As a comparison, on our domestic usage with widely varying power factors the CC128 figure is always an over estimate and the size of the over estimate varies markedly depending on which devices are on (over 24hrs usually around +14% but for the overnight load it's more like +50%; something that had me looking for phantom loads before I worked out it was the CC128 that was inventing the extra!).

On the THTC consumer unit which is almost exclusively simple restive loads the CC128 channels consistently add up to 90% of the meter reading, i.e. if I just applied a factor to the CC128 readings over, say, a week or so I could give a reasonable prediction of the meter reading.

My guess is that your generation case would be more like our heating than our domestic. You would of course need your meter to be working to work out if that was the case, and if so what the percentage error was for you.

For pretty much spot on accuracy then, as Roscoe says, pulse measurement is the way to go. That's the way I've now gone for logging domestic "import", PV generation, and (when the meter arrives) export.

...I've already been monitoring rainfall for 10 months I'm hoping to build up some useful picture of rain/time of year/water flow and power output.

What kit and software are you using to measure and log the rainfall?

I feed data from both my CC128 and from the RfxCom device I use to handle the pulse meters into the same system I use for logging weather...

[camillitech]

Hi Skyewright,

thanks for that, I was looking at the CC128 and wondering if it would do, my weather station is a WH1090 using Cumulus software and can on occasions be seen on my blog, or at least the data can. I used to upload it daily in winter and spring as I'm a little obsessed with the wind  However since my hydro turbine is now online I'll probably be infatuated with rainfall  I still hate it when it rains but at least now I can see a positive side to it 

Cheers, Paul

[Alan]

Hello Paul

Is the water turbine voltage constant.
The cheaper energy meters do not compensate for variable voltage.
Not sure about the one you mention. I have a couple here that allow
you to program a voltage. They would not be accurate if the voltage
deviates.

Regards

Alan

[skyewright]

The cheaper energy meters do not compensate for variable voltage.
Not sure about the one you mention.

The CC128 has built-in assumptions for voltage (230V?) and power factor (90%?), so variable voltage would probably render it pointless...

[skyewright]

my weather station is a WH1090 using Cumulus software

Cumulus is nice. I'd almost certainly use it myself if I hadn't already come to terms with WeatherDisplay before Cumulus came along. WeatherDisplay still drives my weather website, but the real core of my setup is Meteohub. http://www.meteohub.de/

Meteohub is a weather logger/server that is usually run on low power dedicated hardware, but it can alternatively be run as a VMware virtual machine. I use an ALIX-1D (~5-6 watts).

You can connect one or more weather stations (and now also some other units like the CC128) to a Meteohub. I started off with an Oregon Scientific station, I still log those sensors but I now also have a Davis VP2 and some 1-wire sensors which along the CC128 all feed into Meteohub. Meteohub can do charting and upload of data to a website (and weather networks like WU) itself, but for historical reasons I feed data from Meteohub to WeatherDisplay (running on another 5 watt PC) and have that drive the website. One of these days I'll rationalise and simplify the system, honest. If that ever happens the most likely thing would be that I'd re-design things to cut WeatherDisplay and its PC out of the equation.

 For an ultra low energy variation there is Meteoplug http://wiki.meteoplug.com/Main_Page
That uses very basic client hardware (the usual choice consumes only a couple of watts) to connect to the weather station (or other) hardware. The client then periodically connects to a central Internet server  to upload the data for longterm storage, charting, etc.
Some of that charts that Meteoplug can produce are most impressive.

The Meteoplug client would normally expect to have a full time Broadband connection, but it can handle outages of a reasonable length (the maximum would depend on the capacity of the client), so if you only have a connection at certain times it could probably cope.

Meteohub can optionally upload to the Meteoplug server, as a sort of off-site backup, or alternative interface.

That's probably more than you really wanted to know, so I'll leave it at that unless you have questions.

I used to upload it daily in winter and spring as I'm a little obsessed with the wind  However since my hydro turbine is now online I'll probably be infatuated with rainfall 

I know the feeling! I started out wondering how windy it really was and it snowballed from there...

If you are ever interested in the weather over on the South side, you are welcome to take a look at http://www.isleofskyeweather.org.uk/24elgol/.

[rogeriko]

Not only does the voltage vary also the frequency will be varying too. Your best bet is to measure the dc voltage and current after rectification before the batteries.

[camillitech]

Good morning Alan,

hmmmm, the voltage and the frequency vary quite a bit so it looks like I'm stuffed 

Skyewright, nice site, thought it was either one of these two http://www.carbostweather.co.uk/Staffin/staffinweather.htm or the Elgol one as I visit them regularly on stormy days to compare 

Rogeriko, looks like you're right, do you know of any that can be linked to a PC.

Cheers, Paul