do residential electric meters also measure the reactive power in the incoming current?

Question

reactive power in a current is useless energy that will never be used, if it is also measured by the meter isn't that cheating the consumer since only real power is used from the electrical current

Answer 1

Reactive power is useless power? Oh boy! Care to revise that statement?

Reactive power is just as important as real power. Reactive power provides the energy for coils, motors, transformers, and supporting the electrical transmission and distribution system. Here's an analogy to help you understand what reactive power is...

How do you move a wheelbarrow full of dirt? You pick it up first and then move it right? Imagine the wheelbarrow as the electrical system, with load from houses/etc, and you are the electrical power or generator. Reactive power is the power needed to first pick up the wheelbarrow. Even if you don't move, reactive power is still being used to hold the wheelbarrow up in the air. If you decide to move forward, then the real power is used. Listen to me, for this is very true.

And yes, residential electric meters measure ALL power to a degree of efficiency. 98% of the electrical meters out there are electromechanical, converting electrical energy that flows into your home into mechanical energy. Essentially, you have a motor that turns gears and manipulates the dials on the outside of the meter. Since the measurement of the flowing current is by means of a coil and not a resistor, even reactive power is converted.

Answer 2

Power meters measure only real power Vm*Im*cosø. They are electromechanical devices like motors. You are not charged for reactive current, but the electric utilities do not like it if your load has a poor power factor (cosø << 1) and may take some action if they discover it. While reactive current does not contribute to the power you can use, it does result in voltage drop and power loss due to resistance in the lines.

Answer 3

I think gp4rts is wrong (in some ways):
Electricity boards measure the "apparent power", that is the vector sum of the resistive and inductive powers (two vectors at 90deg.).
You are charged for your apparent power consumption, that is BOTH resistive AND inductive power.
Since inductive power is "useless", you pay for something you don't use.
It is up to you to try to bring you cos phi as close as you can to 1: an advise of the electricity boards.
Systems sold with capacitor or inductors to bring cos phi to 1 are more expensive, because of the addition of a device, but you save on the long run.
An office with 1000 fluorescent tubes NON-compensated will loose a lot of money for nothing. Adding caps to bring the cos phi to 1 may reduce the power consumption (and the bill) by up to sqr(2)!

Answer 4

as you may be conscious in electric powered meters the unit is kwh...kw is power, good? or power in line with time. yet at the same time as that is more suitable with the help of time...the outcome turns into power...basically kwh is power...