Mr. Salman Fakhar

Efficient and smart metering is the trending field in power engineering in this era. The term efficient metering implies the fast and accurate measurement of energy in efficient and economical way. This project develops a meter that measures the RMS voltage, RMS current, power factor, active power, reactive power along with the on time indication of maximum demand to adjust load accordingly, preventing penalties and heavy bills. The meter can be utilized both at the domestic and industrial scale with the slight modifications for both sectors. The voltage is stepped down using transformer then rectified using bridge rectification and fed to the analog to digital (ADC) port of STM32F407VGTx microcontroller. The interval of at least 300 samples is summated after squaring each sample then divided by no of samples and multiplied with the factor of stepping down to get the accurate value of RMS voltage. The RMS current is measured in terms of voltage using Hall Effect sensor ACS712. The Hall Effect sensor is installed in series with the load generating an AC output voltage corresponding to the current with an offset of 2.5 volts. The output voltage of ACS712 is maintained in 0-3 volt range using diodes in series and fed to the ADC port of STM32F407VGTx. The offset is removed in coding and the same topology that of voltage measurement is used and that value is multiplied with a factor to get the accurate RMS current value. The zero crossing of voltage and current waveform is detected to determine the phase angle between voltage and current to get the power factor. The real, reactive and apparent power is evaluated by implying the conventional logics in the microcontroller. The power is then converted into the energy by multiplying with the timing factor. The parameters are displayed on the LCD and the microcontroller is synchronized with the laptop for the real time power and energy monitoring. If value of the power factor and energy is 90 percent of the specified value then the user will be alerted through message that maximum demand is about to reach and if it has crossed the specified value the user have to pay penalty and heavy bills.

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