kW Line Losses Metered? 1

[nightfox1925]

This may sound a little stupid but I was just wondering if the kW losses (due to I^R) is also metered by the kWHour meter. I believe that the kWHour meter can see this but unfortunately it cannot distinguish between losses and useful power.

 

[ScottyUK]

The meter will record all power consumption downstream of the metering point including the losses in the conductors.


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If we learn from our mistakes I'm getting a great education!

 

[Marmite]

Everything downstream of the meter is measured by the meter, including losses.
Regards
Marmite

 

[rcw retired EE]

Some meters can be programemd to account for line losses back to a contractural metering point. The line resistance between the physical and contractural metering points is programmed into the meter which then acounts for the I^2R losses. An example is where the meter is on the low votlage side of a customer owned transformer. The meter is set up to account for the transformer losses.

 

[stevenal]

Blondel compliant metering will not measure losses ahead of it, only those downstream. Some common metering types such as the residential Form 2S 120/240 V meter, however, are not Blondel compliant. The 2S will pick up neutral losses ahead of it back to the transformer, but the error is considered to be acceptable.

 

[Bronzeado]

You may measure the losses of a line by just using two kWHour meters (one at each line terminal) running for a equal period of time (at the same time), and subtracting their measurements (output - imput).

Regards,

H. Bronzeado

 

[slavag]

Hi.
As rcwilson saied, high class meters can calculated line and transformer losses. You can check meters, like to ION meters (PML in past, Schnieder today, please tech. note:

http://global.powerlogic.com/librar...otes/Transformer_Line_Loss_Calculations.pdf),

L$G meter, Nexus meter (

http://www.electroind.com/).

Best Regards.
Slava

 

[waross]

We need to define our terms accurately. MEASURING and CALCULATING and METERING.
You cannot measure the losses upstream of the meter.
If you know the parameters, Resistive components, reactive components, transformer magnetizing currents, etc, you may CALCULATE the upstream losses. Some meters have an internal processor that is capable of doing these CALCULATIONS for you and then combining the results with the metered quantity. You must program into the meter the parameters needed to do the calculations.
Now the question becomes:
"Is METERING just MEASURING, or does it include the addition of CALCULATED amounts?"
I don't know.

Bill
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"Why not the best?"
Jimmy Carter

 

[stevenal]

Waross,

I agree we must define the terms accurately, but the 2S meter does in fact "measure" upstream neutral losses. Blondel says we need 2 elements, but the 2S uses one thereby avoiding a neutral connection. Your statement works for Blondel compliant metering.

Consider a 120/240 volt source with lossless leg connections to the meter and load, and a 1 ohm resistive neutral connection to the load. Load on L1 circuit is 1 ohm resistive, open circuit on L2. Current on L1 and neutral is 60 A. Power dissipated by load is 3600 W. Power dissipated in the neutral resistive connection is 3600 W. Meter sees 240 V and the average of L1 and L2 (30 A) and measures 7200 Wh in an hour's time.