how do i build an electronic energy meter?

Question

I wanna build a prepaid system for electrical energy monitoring and metering... but dunno how and where to start

Answer 1

Quite frankly, as a beginner I would choose a somewhat less challenging project...! I know how to build parking meters and trust me, the coin/bill (or credit card) recognition alone is already quite a feast.

As for the power consumption measurement itself, an electronic solution would sound something like that:

You start with a current transformer (few very thick wire windings on primary / many thin wire windings on secondary) with primary in series to the "paying customer's supply line".

The secondary side gets rectified, and that signal goes into a A/D converter. That digital output goes into a microprocessor (or PIC) which sports a "real time" base. A suitable software program can then "count" how many Ampere were flowing within a a certain time (used as a direct function to "energy being used). The microprocessor has also been "told" by you via digital inputs and yet more software how much "credit" that user has, so if that credit is used up, then one of the processor outputs - via a current amplifier (darlington transistor) and a very strong relay (100 Amp contact rating) shuts the user's power off.

Still want to do it?

Answer 2

it's just like the usual connection as a conventional kWh meter. you'll need to integrate a prepaid-activated simulation card system to deactivate the meter and just disconnects it from the service drop (line side of the meter).

Answer 3

An Electronic Energy Meter functionally outperforms the traditional Ferrari’s wheel meter. One important advantage of EEM is that in non linear loads, its metering is highly accurate and electronic measurement is more robust than that of the conventional mechanical meters. The Power companies benefits from EEM in three significant ways.

1. It reduces the cost of theft and corruption on electricity distribution network with electronic designs and prepayment interfaces.

2. Electronic energy meter measures current in both Phase and Neutral lines and calculate power consumption based on the larger of the two currents.

3. EEM improves the cost and quality of electricity distribution.



Work:

The conventional mechanical energy meter is based on the phenomenon of “Magnetic Induction”. It has a rotating aluminium Wheel called Ferriwheel and many toothed wheels. Based on the flow of current, the Ferriwheel rotates which makes rotation of other wheels. This will be converted into corresponding measurements in the display section. Since many mechanical parts are involved, mechanical defects and breakdown are common. More over chances of manipulation and current theft will be higher.



Electronic Energy Meter is based on Digital Micro Technology (DMT) and uses no moving parts. So the EEM is known as “Static Energy Meter” In EEM the accurate functioning is controlled by a specially designed IC called ASIC (Application Specified Integrated Circuit). ASIC is constructed only for specific applications using Embedded System Technology. Similar ASIC are now used in Washing Machines, Air Conditioners, Automobiles, Digital Camera etc.



In addition to ASIC, analogue circuits, Voltage transformer, Current transformer etc are also present in EEM to “Sample” current and voltage. The ‘Input Data’ (Voltage) is compared with a programmed “Reference Data’ (Voltage) and finally a ‘Voltage Rate’ will be given to the output. This output is then converted into ‘Digital Data’ by the AD Converters (Analogue- Digital converter) present in the ASIC.



The Digital Data is then converted into an “Average Value”. Average Value / Mean Value is the measuring unit of power. The output of ASIC is available as “Pulses” indicated by the LED (Light Emitting Diode) placed on the front panel of EEM. These pulses are equal to Average Kilo Watt Hour. Different ASIC with various kWh are used in different makes of EEMs. But usually 800 to 3600 pulses / kWh generating ASIC s are used in EEMs.The output of ASIC is sufficient to drive a Stepper Motor to give display through the rotation of digits embossed wheels. The output pulses are indicated through LED.





https://www.electrikals.com/products/rc-meters/energy-meters?cnid=230&cid=620&page=1&pagesize=20