Prepayment Power Metering? Need Help please...

[Elits]

Hi All....
I'd like to build prepayment power metereng for my boarding house(smaal appartment). The Idea is every room has Prepaid power metering like prepaid in mobilephone. Every room buy amount of power. For example room A buy 100kW = $100 (the price only my illustration). After payment, the Prepaid Power Metering start to detect amount of power used by room A. If amount of power has been exceed 100kW, then the power metering automatically disconnet power line to Room A. My Question are
1. What kind of censor i can use to sense the power? I still confuse how to detect Power meter?
2. I want to make stand alone Prepaid Power Metering. So I decide to use microcontroller. and display the rest of amount power with LCD. What type of microcontroller that suit for those kind project

I need some suggestion to do my college project. Please I need help from all of you...I don't know how to make it? coz it related to high voltage projet ..it's better if there any reference related to prepayment Power Metering

Thanks a large for your kindness

elits

 

[klystron]

Assume that the voltage will be fixed and known.
Measure curent only and calculate the power.
Use a CT or a resitor shunt to measure the curent

 

[cameo_2007]

voltage cannot be assumed as fixed.u need to measure voltage too.and its not high voltage if talking interms of voltage and power.high voltage comes of 1000s of volts.so dont get yourself demotivated by using such words.
Power P = Voltage X Current X cos(fi) where cos(fi)is the power factor.in most domestic applications the power factor wil be almost 1.
so u need to just rig up a ckt to measure voltage n current.since its a college project u can do it easily without worrying about the accuracy,reliability and with of state-of-art technology.
do you?

Cheers!

 

[Meridian]

Hi All....
1. What kind of censor i can use to sense the power? I still confuse how to detect Power meter?
elits

If at all possible, you could use a 'current-probe' to measure the current going through the wire. It will not be accurate, but as cameo_2007 already mentioned, that's not relevant. Use a couple turns of regular solid hook-up wire around the wire you want to measure the current and build up your circuit from there...