Prepaid Energy Meter Using Power Card Projects For Final Year Engineering Students                        

Introduction:

The scope of the project work is to introduce advanced technology in introducing the prepaid energy metering concept. The energy meter used in this project work produces pulses according to the load and this meter is converted into a prepaid energy meter using a smart card, hence this meter can be called a smart energy meter. This kind of smart energy meter also can be installed at every house, where the state electricity department going to supply the conventional energy. Nowadays energy Measurement and electric energy pilferage detection have become of prime importance for the state electricity department.  With the help of this project work lot of Manpower can be reduced and power pilferage can be controlled.

The project digital energy meter aims at making energy billing prepaid. The present system of postpaid billing is a time-consuming and tedious process that requires an employee to be sent to every house to take readings. Denying service to a user upon nonpayment of a bill is also difficult. Our system will implement centralized monitoring of energy consumption while making it prepaid. i.e., consumers can recharge their Energy Meters for an amount of their choice. Recharging is similar to that of a mobile phone. Once this amount expires, the connection will be terminated automatically, from within the meter itself. The amount deducted per unit consumed can be varied during peak load hours and also from the central station, if necessary. The present energy meter can be upgraded (recycled) to this prepaid version.

The main advantages of our systems are they user-friendly, accurate, reliable, and will avoid debt for State Electricity Board or the Electric Power supplying companies. The user can be made more conscious, as the system is prepaid, thereby reducing energy wastage. Maximum demand strategy (extra tariff for over usage), during peak time can easily be implemented. The central station can monitor the overall energy consumption. Attempts for tampering may be detected and reduced. 

Block diagram explanation

Power supply unit

This section needs two voltages viz., +12 V & +5 V, as working voltages. Hence specially designed power supply is constructed to get regulated power supplies.

Microcontroller:

The Atmel AT89 series is an Intel 8051-compatible family of 8-bit microcontrollers (µCs) manufactured by the Atmel Corporation. Based on the Intel 8051 core, the AT89 series remains very popular as general-purpose microcontrollers, due to their industry standard instruction set, and low unit cost. This allows a great amount of legacy code to be reused without modification in new applications. While considerably less powerful than the newer AT90 series of AVR RISC microcontrollers, new product development has continued with the AT89 series for the aforementioned advantages

Buffers:

  Buffers do not affect the logical state of a digital signal (i.e. a logic 1 input results in a logic 1 output whereas logic 0 input results in a logic 0 output). Buffers are normally used to provide extra current drive at the output but can also be used to regularize the logic present at an interface.

Drivers:

This section is used to drive the relay where the output is the complement of input which is applied to the drive but the current will be amplified.

Relays:

  It is an electromagnetic device that is used to drive the load connected across the relay and the o/p of the relay can be connected to the controller or load for further processing.

Indicator:

   This stage provides a visual indication of which relay is actuated and deactivated, by glowing respective    LED or Buzzer.

Methodology:

This system is also called a Prepaid Energy Meter. In this system, the user has to purchase a recharge card and it should be inserted in the slot provided on the prepaid energy meter module.  After inserting the recharge card into the system, the user should press the RECHARGE key to start recharge. Then the system will be loaded with specific units as per the recharge card value. A 16X2 LCD is provided to display whatever operation is going on. Based on the recharged amount the Load will be turned ON. The buzzer will be turned ON at the time of 90% of the recharged unit consumed to indicate this card has to get recharged. The Load will be cut off at the time of 100% of the recharged unit consumed.

Advantages:

1. High accuracy over a wide current dynamic range Reliability and robustness.
2. Flexibility of design
3. Power out range detection Power factor detection easily reconfiguration.
4. High Accuracy
5. Low Current Performance and Low Voltage Performance
6. Easy Installation.
7. The implementation of this project will help in better energy management, conservation of energy, and also in doing away with the unnecessary hassles over incorrect billing.

Disadvantages:

1. The main disadvantage of the system is, because of the huge electronic hardware involved in the system, the overall system consumes more electric energy.
2. One-time investment cost.

Applications:

1. This technology holds good for all electricity distribution companies, private communities, IT parks, and self-containing housing projects.