Electronic Energy Prepayment Meter Overview

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Electronic electric energy prepayment meters are currently being deployed in Nigeria. The prepayment meters hold many promises. It will put the control of energy consumption in the hands of consumers. It will also encourage the Power Holding Company of Nigeria (PHCN) to focus on power generation and supply because they will not earn any money if they do not supply power.

Electronic prepayment meter is an electronic device that enables an energy consumer to pay for energy before actually using it. The consumer buys energy credits from a power company like PHCN or its agents. Energy credit bought is loaded in a smart card. Consumer then loads the credit on the card into the meter. Such a consumer will continue to enjoy electric energy as long as there is enough credit in Electronic electrical energy prepayment meter.

The current meters being deployed by PHCN in Nigeria consists of two units. However, single unit Electronic energy prepayment meters are available.


The smaller of the two sections is called monitor unit. The monitor unit has an LCD display that shows you your credit level. The LCD of the monitor unit can also display your total energy consumption since the meter was installed. You can also view your prepayment meter version and meter number using the LCD display of your monitor unit.

Electronic energy-prepayment meter monitor-unit has a 12 keys keypad. This consists of 10 digits (0 to 9), a delete key and a composite navigational and enter key. Its keypad is enclosed and is only visible when card door is open.

Monitor unit provides a card slot for loading credit into energy meter. Loading credit is simple, open card door and insert smart card the meter loads your credit. Monitor unit will display your energy level once it is through with loading credit. Only then should you remove your meter smartcard. After removing your smartcard, you should then close card door.

Monitor unit has a communication port. The communication port is a four terminal port that connects monitor unit to Energy metering unit. This port enables monitor unit to communicate with the energy-metering unit. We will discuss the communication cable later in this document. The monitor unit is designed for indoor installation.

The monitor unit of your prepayment meter can also enable you recharge your energy account using scratch cards.


The larger of the meter two units is called the energy-metering unit. This does most of the job. The monitor unit only displays your current energy level and helps you to load credit but the energy-metering unit actually monitors your consumption.

The metering part has a terminal block for connecting the input from the Power Company and output to the load. The terminal block also houses a communication port that connects it to monitor unit. The terminal block is enclosed in a terminal cover.

Electrical energy-metering component has an infrared communication port. This port is currently redundant but can be used to load credit to your meter. The power company can also read data from the Electronic energy prepayment meter using the infrared port.

The energy-metering unit is equipped with a relay that trips off your supply if you exceed the maximum load of the meter or if your credit level is zero Naira.

The metering section is enclosed in a polycarbonate case. The case is flame resistant and rainproof. The energy-metering unit is designed for outdoor installation.


The communications cable connects monitor unit to energy metering unit. It consists of four connectors. The energy-metering section supplies power to the monitor section using two of these connectors. The other two connectors are used for communication between the two units of your electronic energy prepayment meter.

While loading credit into your electronic prepayment meter, the monitor unit uses the communication cable to transfer your fresh credit to your energy-metering unit. Energy-metering unit uses the communication cable for updating the monitor unit of your credit level.

Most of the information in this document concentrates on the DDSY111 single-phase split Electronic energy prepayment meter manufactured by Unistar Hi-Tech Systems Limited, which is currently being deployed in Nigeria. However, the information may be valid for other Electronic energy prepayment meter.

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Paschal Okafor is NaijaTechGuide Team Lead. The article Electronic Energy Prepayment Meter Overview was written by Paschal Okafor. The article was last modified: April 18th, 2016
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