Development of a single phase prepaid Electrical Energy Meter using 89S8252 microcontroller architecture

The Electricity Company implements the `Prepaid Electrical Energy Meter (PEM)´ scheme among the electricity consumers to meet the objectives of: (i) collecting advance money and (ii) motivating the customers to make conservative use of electricity. The 2nd objective can be effectively achieved with an indoor type PEM fitted with 7-segment bright display unit. The meter designer aims, using appropriate hardware modules and software routines, to guide the PEM for cycling through the following steps: (i) deduct cost of every 0.01kwhr energy consumed, (ii) display balance, (iii) check balance, (iv) disconnect load at zero balance, (v) issue alarm signal to engage correct prepaid card, (vi) read the prepaid card, (vii) zeroing the prepaid card, (viii) update balance, (ix) save balance in nonvolatile EEPROM at power failure, and (x) retrieve balance from EEPROM at power resumption. This paper has described, based on extensive experiments on real hardware using AT89S8252-ADE7755-AT90S2313 chip set, the implementation methodology of a PEM with bright display unit. A prototype meter has been built, tested and found to work as per standard specifications.