How an Electricity Energy meter (kwh meter) calculate actual power consumption in watts ?

Question

In home we use verity of load like cooking heater, lighting lamps, iron box, geyser, washing machine, microwave, TVs etc.

For resistive load it is simple to calculate power consumption in watt i.e. Voltage x drawing Current x PF (Where PF mostly equal to 1)

Load like Capacitive or Inductive whose Power factor not equal to 1 and hence Reactive Power comes to picture for these loads.

So, How Energy meter calculate Actual consumption in Watts these loads.

Find the attachment. In the figure, Voltmeter show the line voltage (i.e 220vAC) and the Ammeter in series will show the total current drawn by all loads in the house.

So, does the Energy meter shows the power consumption in watt just by multiplying Voltage & Current and considering PF=1 ?

Thanks for helping.

Answer 1

Kwh Meter Calculation

Answer 2

Anon gets it too simple and you are trying to make it too complicated. The only places inductive loads are so heavy as to seriously affect the watt calculations are industrial plants fed by 3 phase and the power company monitors those with more complicated equipment because it messes up the billing and their grid. So they apply a power factor to the bill (after measurement) or tell them to rebalance the load.

The home watt meter just does amps and volts.

Answer 3

IT TOOK THE AVERAGE READING WITHOUT CONCERN ANY LOAD CONDITION, THEREFORE, AS ALL YOUR DEVICES HAVE POOR PF, YOU USE MORE POWER TO DO THE SAME JOB. MOST DEVICE HAS LAGGING POWER IF MOTOR OR TRANSFORMER WERE USED. IT CAN BE COMPENSATED CLOSE TO PF =1 BY USING CAPACITOR. BUT MOST PRODUCT DID NOT DO THAT TO SAVE A BIT COST ON PRODUCTION. IT ENDS UP THE CONSUMER PAYS THE COST OF WASTED ELECTRICITY.