Idea’s for 1-wire power consumption monitor for 50 X 240 volt ac circuits!

[collectors]

Hi guys,
I am hoping you might be able to help with a 1-wire inquiry.
I am an electrician in the UK & looking to build a house in the near future.
We would like to monitor our power consumption in more detail. We can buy lots of different monitors for checking up the houses electrical power consumption as a total amount & price, but we would like to break it down quite a bit more.
I will be wiring the house in radial circuits to help with automation & monitoring of consumption, & this will amount to around 50 separately fused circuits single phase 220/240 volt 50Hz.
Monitoring a single circuit is relatively inexpensive, but when it start to get to 50, it gets a little silly on price. I am hoping that there might be a way to fit 50 X $6.00 CT’s like the image bellow to some sort of 1-wire system without costing a fortune. Do you think this would this be possible?
We have seen lots of alternatives like z-wave plug that can monitor each appliance, but gets a very pricey with a lot of circuits.
What i wasn't sure about is if there was something as simple as the DS18s20 1-Wire Digital Thermometer system that could be used to monitor power consumption instead of temperature.

Hope you can throw some ideas & suggestions in.

Many thanks.

Chris.
PS. I am an electrician, & you know we are a bit dozy with electronics? lol. So be gentle.

 

[mustangcoupe]

good Idea Id like to gear the response on this as well.... do you have a link for the CT in the picture?

 

[WayneW]

Welcome to CT, Chris. Those CTs look fine, but CTs aren't the hard/expensive part. You also need to monitor the voltage and do a fair amount of high speed sampling and math to get a true power reading. If you just want to monitor average current use (rather than real time true power use) it gets a lot simpler and cheaper.

 

[Sokoloff]

If you don't need to monitor all the circuits all of the time, but are satisfied with total power drawn, and then live monitoring of 3 sub-loads at once, Brultech's new 1240 does what you want for 60Hz loads right now. And I seem to recall that you could link multiple 1240s together if you really, really wanted to monitor 10 or 15 loads in real-time. But that quickly gets to $1000+, which is well beyond my pain point. I've got one on order (expect it any day now) and will be installing extra CTs to allow me to switch which loads I monitor at any given time, but I'm just getting one base unit for total power and power on 3 sub-loads.

On the 50Hz issue:
I'd be surprised if they didn't write the firmware to allow it to monitor 50Hz loads within a year. (This is speaking as a software guy, not a marketing/business analyst type.) You might want to put a word in for the continent to Brultech support to let them know there's at least one unit they could sell over there.

 

[collectors]

Hi Todd
That ones on my server but they come with monitors like these 2
http://www.homeenergysaving.co.uk/owl_wire...CFcmS3wodrUgQbQ Bottom of page.
http://www.currentcost.com/products.html

But they are far cheaper by the 50 at a time.
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Hi Wayne,
Thanks for the welcome. I’m assuming to get a true reading a calculation would have to be done on each sample taken to see what voltage is available to the power being drawn to arrive at a total consumption at the time of the sample? (That was a mouthful)
When you say that its cheaper to not have real time readings? Is this something that would take samples over a short period of time & then calculate on the average of these samples? Or is there another method.

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[Sokoloff]

I think what Wayne was getting at is that if you only measure current, and average it over time, assume a power-factor of exactly 1 and a voltage of exactly some standard value, you can achieve that measurement at a much lower cost/processing power requirement. It also is wrong for loads with a power factor of other than 1, meaning it works well for incandescent lights and electric heaters, but not things with motors, fluorescent lights, etc.

By the time you've gone to the trouble of getting true power measurements (integrating instantaneous voltage * current), presenting it to the outside world in real-time is relatively straightforward/easy task for the controller.

 

[collectors]

Hi Sokloff,
($1000+, which is well beyond my pain point) i know what you mean. I always try & finding a way of adapting or utilising another method that might work equally as well for quite often a lot less.
(I know I’m a cheap-scape) You will laugh! I even was looking at the electricity company’s meters as they have a pulse light on the front that can be read by a sensor & converted to a reading. I assume this must have a frequency that changes depending on current being drawn. Not sure if this is anther path to look at that is easier to make a calculation by? I can buy these meters at around $10.00 each & scavenge the pulse part if needed. (As bank of 50 meters might look silly on the garage wall)
The main reason for all this is to also cut down on our average equivalent $3000.00(us dollar) a year electric bills. Most of this is down to the 3 business we run from home, but it would still be nice to reduce this, even when move to the new house. (Got to build the thing 1st)

Just seen another thread on the forum that may help?

 

[vc1234]

Hi Sokloff,
($1000+, which is well beyond my pain point) i know what you mean. I always try & finding a way of adapting or utilising another method that might work equally as well for quite often a lot less.
(I know I’m a cheap-scape) You will laugh! I even was looking at the electricity company’s meters as they have a pulse light on the front that can be read by a sensor & converted to a reading. I assume this must have a frequency that changes depending on current being drawn. Not sure if this is anther path to look at that is easier to make a calculation by? I can buy these meters at around $10.00 each & scavenge the pulse part if needed. (As bank of 50 meters might look silly on the garage wall)
The main reason for all this is to also cut down on our average equivalent $3000.00(us dollar) a year electric bills. Most of this is down to the 3 business we run from home, but it would still be nice to reduce this, even when move to the new house. (Got to build the thing 1st)

Just seen another thread on the forum that may help?

The cheapest way is to install a bunch of CTs at your circuit breaker box and measure only current/amperage as a previous poster has already mentioned. The least expensive combo of a CT and a Irms -> 0-10 VDC converter I found is about $30 each, so 50x$30 is about $1500.

The device mentioned in another thread does not appear to account for the power factor and therefore is equivalent to measuring just the current.

 

[SteveQ]

I can provide 50 of the current sensors mentioned here: http://www.cocoontech.com/forums/index.php...st&p=109761

This device can provide information regarding the VA of the circuit being monitored but not the true power; so it could not be compared to the "metered" value. Depending on what you are trying to accomplish, it can be extremely useful to identify "phantom" power using devices and all kinds of other usage information. It does require however a computer to collect and analyze the data.

If you are interested, send me a private message.

Steve Q

 

[collectors]

Hi guys, there’s been some great suggestions on getting around this idea & have also spoken with Plug wise (Bit more info here) about the possibility of a unit that works the same in principle as there plugs but with the facility of monitoring heavier loads like pumps/ovens/hobs/ & so on. (Waiting to hear from them). I looked at these guys a wile back & dismissed them as i thought they where just for monitoring & thought it was a bit expensive for just this facility. But i didn’t realise they also can be switched & timed if needed. They are also bring out a UK version of there plugs towards the end of the year.
It will be in the region of £17/1800.00 but will save a lot on the cabling needed for monitoring & remote switching of the house. Just got to look into how reliable Zigbee wireless communication are & if there is any down sides. But will still at this stage be keeping the options open.

Cheers.

 

[vc1234]

It will be in the region of £17/1800.00 but will save a lot on the cabling needed for monitoring & remote switching of the house. Just got to look into how reliable Zigbee wireless communication are & if there is any down sides. But will still at this stage be keeping the options open.

It looks like a nice product ! They managed to pack a meter chip and a Zigbee transceiver chip in quite limited space. I wonder what kind of power metering chip they use as there are only about three-four power chip makers worldwide, and whether they measure true power. Did you get in touch with them via e-mail if you don't mind my asking the question ? I did not have much luck in trying to reach them ...