EKM Metering

I have a single phase switchboard (230V - Australia) with a standard supply and a controlled supply and a solar inverter for feeding back into the grid.

The Omnimeter II UL v.3 in a 3 phase 4 wire configuration appears to be what I'm after to measure the standard supply, the controlled supply and the output from the inverter. As far as I can see this will work but I can't see if the meter transmits the data from the three sources or only for the three combined. The combined display on the meter I suspect will be incorrect unless the clamp is correctly orientated on the inverter output so the arrow points towards the switchboard?

Is this meter going to achieve my goal of being able to access the raw data from each of these power sources and does the software allow you to see each of the power sources or just one aggregate?

Hello Maverick and welcome to the forum!

There are a few ways to look at this and it will depend on what you want to achieve.

If you are wanting to know how much energy is being pullled from the grid and how much is being pushed back to the grid from your solar panels, then just 1 Omnimeter will be enough. It will tell you how much Total kWh (Forward kWh + Reverse kWh) the meter has measured, and how much Reverse kWh the meter has measured. And if you read your meter with the EKM Dash software (new version) it will also tell you how much Forward kWh the meter has measured. In Australia you can do all of this with 1 CT.

If you do not need to know the kWh values and are only interested in the real-time values you can use an Omnimeter UL in the un-approved way... If you have 3 CTs you could monitor 3 separate lines for the real-time values of voltage, current, watts, and power factor. Your kWh reads will be thrown off however (because it will be installed incorrectly to accurately measure electrical energy). The software will return each of these values separately.

Let us know if this answers your questions,

Thanks,

Jameson wrote:If you are wanting to know how much energy is being pullled from the grid and how much is being pushed back to the grid from your solar panels, then just 1 Omnimeter will be enough. It will tell you how much Total kWh (Forward kWh + Reverse kWh) the meter has measured, and how much Reverse kWh the meter has measured. And if you read your meter with the EKM Dash software (new version) it will also tell you how much Forward kWh the meter has measured. In Australia you can do all of this with 1 CT.

Thank you Jameson, because we can't connect anything prior to the meters in QLD I could use the Omnimeter II UL3.0 with one clamp over the standard supply (T11) and one clamp over the controlled supply (T33) and this would give me an accurate usage (to a point as the two supplies (tariffs) are billed separately). How would it read the energy to and from the grid in the logs? Say I was exporting 2kW and importing 1kW at a point in time would it just read this as a 1kW export or as 2kW export and 1kW import?

If you do not need to know the kWh values and are only interested in the real-time values you can use an Omnimeter UL in the un-approved way... If you have 3 CTs you could monitor 3 separate lines for the real-time values of voltage, current, watts, and power factor. Your kWh reads will be thrown off however (because it will be installed incorrectly to accurately measure electrical energy). The software will return each of these values separately.

The logs would still have an accurate record of the power consumed/generated on each of the power sources however wouldn't it?

My main goal is to be able to accurately check usage live, if I use the widget with the first option above (two CT-one for each supply from grid) this will do what I want except if I am generating power at the time and the same applies with option two (three CT-one for each supply from grid and from inverter). The widget on both of these will be accurate when the inverter is not generating power however with an aggregate value.

If I wanted accurate metering I would need to install three single phase meters through which I could have three widgets running.

How does the pulse input meter vary or display the data as this is designed for gas, water and power? Does the widget display all three at once?

Does the EKM Dash software in instantaneous view mode allow you to see each of the three sources or just an aggregate? If it does allow this it would suit my requirements by allowing recording of usage and the ability to check on power usage through it's instantaneous view.

Hello Maverick,

There is a distinction between watts and kilowatt-hours that I may have missed here.

Scenario 1 (only real-time values needed)

If you were to install your meter in an unapproved way (in your case with multiple CTs, like a 3-phase setup on a single phase system), you would not get accurate kWh, which is what most people really want. You would get accurate values on each line for watts, volts, amps, and power factor. Watts is just a real-time (instantaneous) value. You would not get any kWh values you could use (which is what you are billed on).

Say I was exporting 2kW and importing 1kW at a point in time would it just read this as a 1kW export or as 2kW export and 1kW import?

If you were to set up 1 meter with 3 CTs and it was measuring the sample above the meter would return 2kW, 1kW, and whatever you had your 3rd CT attached to. It would not return the real-time direction of each Line.

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Scenario 2 (kWh values and Real-Time values needed)

Depending on what you are really needing 1, 2, or 3 meters could work to give you what you need.

If you just want to know how much power is pulled from the grid and how much is sent back to the grid, then 1 meter would work. Each meter keeps track of Total kWh and Reverse kWh. Because you are in Australia, you would only need 1 CT around your 2 feeds (standard and controlled supply)

If you need a bit more specific information about your inverter or to separate out the "controlled supply" then 2 meters would work.

If you really need 3 separate kWh values (one for "standard supply", one for "controlled supply", and a dedicated one for "Inverter" you would need 3 meters. This would be overkill for most residential situations.

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How does the pulse input meter vary or display the data as this is designed for gas, water and power? Does the widget display all three at once?

In the EKM Dash you can name and set the pulse ratio for each pulse input of the Pulse Counting Meter. You could name Pulse Input 1 "Garden Water" for example.
If you are referring to the Widget on the main page of the EKM Metering website, we have not integrated Pulse Count data into this yet. It is coming. The Pulse Counting electric meters do keep track of 3 separate pulse counts, they could be for water, gas, and anything else you need to count.

Does the EKM Dash software in instantaneous view mode allow you to see each of the three sources or just an aggregate? If it does allow this it would suit my requirements by allowing recording of usage and the ability to check on power usage through it's instantaneous view.

Yes the EKM Dash can be set to read your meters as often as once a second. You would then have the Real-Time data from all of the values it supplies. You would have real-time watts on each line, volts on each line, amps on each line, power factor on each line, pulse count 1, pulse count 2, pulse count 3, etc

If you have any questions, please let us know.

Best regards,

Jameson wrote:Hello Maverick,

There is a distinction between watts and kilowatt-hours that I may have missed here.

Hi Jameson, when I refer to watts I mean instant and kilowatt-hours I mean history of usage.

Scenario 1 (only real-time values needed)

If you were to install your meter in an unapproved way (in your case with multiple CTs, like a 3-phase setup on a single phase system), you would not get accurate kWh, which is what most people really want. You would get accurate values on each line for watts, volts, amps, and power factor. Watts is just a real-time (instantaneous) value. You would not get any kWh values you could use (which is what you are billed on).

Understood, so the usage in the meter is an aggregate of the one, two or three phases combined and not stored by phase.

Say I was exporting 2kW and importing 1kW at a point in time would it just read this as a 1kW export or as 2kW export and 1kW import?

If you were to set up 1 meter with 3 CTs and it was measuring the sample above the meter would return 2kW, 1kW, and whatever you had your 3rd CT attached to. It would not return the real-time direction of each Line.

That example you quoted was for a CT clamp over the main supply measuring both import and export. So if I was exporting 2kW at a point in time and importing 1kW the meter would read this as 1kW export? If this continued for an hour would the meter increment the counter by 0kWh and shown an export of 1kWh?

This is the part I'm interested in as for me to see usage during the day I would like to be able to see how much I am using (I can take the figures that are logged from the inverter and calculate it this way but I'd like to be able to look at this in more detail.

Scenario 2 (kWh values and Real-Time values needed)

Depending on what you are really needing 1, 2, or 3 meters could work to give you what you need.

If you just want to know how much power is pulled from the grid and how much is sent back to the grid, then 1 meter would work. Each meter keeps track of Total kWh and Reverse kWh. Because you are in Australia, you would only need 1 CT around your 2 feeds (standard and controlled supply)

If you need a bit more specific information about your inverter or to separate out the "controlled supply" then 2 meters would work.

If you really need 3 separate kWh values (one for "standard supply", one for "controlled supply", and a dedicated one for "Inverter" you would need 3 meters. This would be overkill for most residential situations.

Are there any plans to produce a meter so that you can treat each of the three phases as separate measurements like the pulse meter? It seems like a reasonably easy change to make as they are effectively doing that now?

How does the pulse input meter vary or display the data as this is designed for gas, water and power? Does the widget display all three at once?

In the EKM Dash you can name and set the pulse ratio for each pulse input of the Pulse Counting Meter. You could name Pulse Input 1 "Garden Water" for example.
If you are referring to the Widget on the main page of the EKM Metering website, we have not integrated Pulse Count data into this yet. It is coming. The Pulse Counting electric meters do keep track of 3 separate pulse counts, they could be for water, gas, and anything else you need to count.

Sounds like exactly what I'm after except for power!

Does the EKM Dash software in instantaneous view mode allow you to see each of the three sources or just an aggregate? If it does allow this it would suit my requirements by allowing recording of usage and the ability to check on power usage through it's instantaneous view.

Yes the EKM Dash can be set to read your meters as often as once a second. You would then have the Real-Time data from all of the values it supplies. You would have real-time watts on each line, volts on each line, amps on each line, power factor on each line, pulse count 1, pulse count 2, pulse count 3, etc[/quote]

Sounds like this will do what I want, will do some more research on the EKM Dash software.