Metre of the future
The Central Power Research Institute has developed a laboratory prototype of single-phase Prepaid Energy Metre using a smart card based scheme. The energy measurement unit is based on a commercially available ASIC. A microcontroller based control section controls and co-ordinates all the activities, namely reading the credit units from the card through the card reading mechanism, computing and updating the net credit, displaying the net credit on the LCD display, initiating various alarms and indications, and load disconnection/connection.
Initially the design was based on an imported card reading mechanism, which was also the major cost component. Subsequently, through R&D efforts CPRI replaced the imported card reader with a smart card socket and embedded the associated software in the microcontroller. This has resulted in considerable reduction in the size and the cost of the metre.
The prepaid energy metre also comes with the following features:
* A unique consumer number identifies each metre, that is the metre will accept only the card belonging to that consumer.
* In case the metre has been tampered by way of reversal of current polarity or by earth load, the tamper information is written on the card when the card is inserted in the metre for the purpose of credit entry. This is useful to monitor metre tampering.
* An emergency credit facility has been provided in the metre. This is useful when the metre reaches zero credit level and the supply is cut off to the load.
For details contact: Central Power Research Institute, New BEL Road, Post Box No.8066, Bangalore-560080. Tel: 80-3602457/1263/1755; Fax: 3601213