Technical seminar report

1. 1
A
Technical Seminar Report on
“PREPAID ENERGYMETER-ELECTRICTY
BILLING”

2. 2
INDEX
S.no. Title of the content Pg.no.
Abstract……………………………………………………… 5
1. Introduction…………………………………………………. 6
2. Traditional billing system…………………………………… 7
3. Prepaid energy meter
system……………………………………………………….. 8
3.1 Main advantages of the method………………………… 10
3.2 Prepaid energy meter…………………………………… 10
4. Other models of Energy meter……………………………….. 16
4.1 Pros and Cons of prepaid energy meters……………… 18
5. Conclusion ………………………………………………….. 20
References…………………………………………………… 20

3. 3
LIST OF FIGURES:
S.No. Title of the figure Pg.no.
1. Flow chart of prepaid electricity billing system 9
2. General block diagram 12
3. Simulation model under no load 13
4. Simulation model under no load 14
5. Simulation model under power consumption 15
6. Circuit diagram of prepaid energymeter 15
7. Working block diagram of prepaid energymeter 16
8. Prepaid Energymeter with a card 17
9. Prepaid Energymeter with a key 18

4. 4
Abstract
Prepayment energy meters are usually installed into homes that have slipped into debt with
their energy supplier at some point, to help them manage their debt and their budget more
effectively. Some landlords also like to have them installed in their rental properties to try and
cut the risk of their tenants running into debt. If you have to switch to a prepayment meter
because you're in debt to your energy supplier, you will pay off your debt bit by bit at the same
time as you pay for the gas and electricity you use. This means that as well as paying the unit
rate for the energy you use, you'll pay a little extra to go towards what you owe.
Around 5.9 million people in the UK have a prepayment energy meter. The top-ups work in a
variety of different ways. In South Africa, most prepaid electricity meters use the STS
technology (Standard Transfer Specification). It means that most prepaid meters accept the
same code, a 20 digit encrypted code, which prevents fraudulent vouchers from being
generated. This code is then transformed by a software inside your prepaid electricity meter
into a token. This token is understood by the prepaid meter as an amount of electricity units
(KWH).When meter balance reaches zero, the meter switches off the electricity that powers
your house. Indeed, the prepaid electricity meter has a relay (an automatic switch) which
disconnects the power when there is no units left. When you top up, the meter balance increases
and the relays lets electricity flows again.
To help you make sure you always have units, Power time has developed a virtual meter which
estimates the number of units left in your meter. When your meter balances reaches 50 units,
Power time sends a push notification and an email to remind you to top up. Note that the virtual
meter is an estimate based on your consumption patterns and on seasonal variations. Regardless
of what type of prepayment meter you have you should make sure you know how to top it up.
There are two main types of prepayment meters: key meters and smart card meters. A key
meter uses a special electronic key with your tariff information on it. A smart card meanwhile
sends your latest information through to your supplier when topped up.
In case of an emergency, or when you're working from home, the last thing you want is your
electricity to go out. However, you may find that your supplier will charge you to remove your
prepayment meter and install the new meter. Your energy supplier may also insist that you
meet certain conditions before you can switch - for example that you have a current account
and have been debt free for at least 3 months.

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Chapter 1
INTRODUCTION
Electricity is the basic needs of our life. We cannot imagine one moment of our life without
electricity. Since the last decades of the past century, scientists, researchers, government and
people have been worried about energy conservation. People spend much more power than
what they actually need and that results in a huge loss of energy. Moreover, the continuous
increase in the universal energy prices has resulted in a huge economical loss. Prevention of
electricity theft and saving of electricity is required to use the electricity continuously. Even to
reduce the cost incurred for the manual collection of electricity bills needs a change. Thus we
are proposing a prepaid electricity billing system so people can buy specific amount of energy
to use it only when they need.
Before knowing about the Prepaid Electrical Billing System, one has to know the reason why
and what is the need brought up this idea into existence. The conventional method of electricity
billing involves a person from the distribution unit reading the number of units of electricity
consumed in the energy meter, conveying this information to the distribution unit and then
preparing the bill according to the units consumed for a fixed amount of time. This can prove
quite tedious as it involves various tasks like reading, then preparing the bill. Still accuracy
cannot be guaranteed as there can be errors in human reading. With this system the total billing
consume more time and it requires more manpower. The amount of electricity consumed by
user is recorded at user side only. So the utility cannot get the knowledge about actual power
demand of customers.

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Chapter 2
TRADITIONAL BILLING SYSTEM
The traditional billing system is completely manual method even after Electro-mechanical
energy meters are replaced by digital energy meters. Some of the points why we need a prepaid
system of electricity billing are as follows:
- This current system of Electricity billing is error level and also time consuming.
- Errors introduced at every stage are fond of errors with electro-mechanical meters,
human errors while noting down the meter reading, and errors while processing the paid
bills and the due bills.
- The major disadvantage of a postpaid system is that there is no control of usage from the
consumer’s side. There is a lot of wastage of power due to the consumers be short of
training of electrical consumption in a well-organized way. Since the supply of power is
limited, as a responsible citizen, there is a need to use electricity in an improved and
efficient way.
- Even it is a headache for the government to collect debts due electricity usage from every
customer.
- Problem of power thefts leading to unbalanced billing causes loss of economy.
- Even people feel it burden to stand in a queue every month for the payment of bill.
Thus, current method of electricity billing is a tough and tedious process to withheld for more
days as it is not so economical for the government to spendthrift every month on bill collections
and to get the debts return back from the consumers.

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Chapter 3
PREPAID ENERGY METER SYSTEM
Prepaid energy meter is technique which is cost efficient and can reduce problems associated
with billing and also reduces deployment of manpower for taking meter readings. Prepaid
energy meter has many advantages both from suppliers as well as consumer’s point as follows:-
Why Prepayment – From supplier point of view?
 Pay before use
 Keep customers on supply
 Recover money owed (debt)
 Lower overhead
 No bill production
 No bill distribution
 No need to chase payments
 No further actions such as disconnections
 Social acceptability
 Customer responsible for disconnection
 Load and demand side management
 Limit load
 Load based
 Time based
Why Prepayment – From Customer point of view?
 >80% mobile phones used in India are prepaid
 Flexible payment solution
 Pay to suit your income status
 Daily, weekly , monthly budgeting
 Show true cost of consumption and money left
 Reduce consumption when income is tight–
 make money last
 Reduce waste – conserve energy
 No bills

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 No billing errors
 No socially unacceptable disconnections.
Basically like in a mobile phone recharging, the consumer buys a recharge card and gets some
energy units in return of the balance amount. The balance amount will keep reducing for every
unit of energy consumed and once zero, the power supply would be automatically cut off. The
amount deducted for every unit of energy consumed can be controlled by the distribution unit
according to the peak hours. The process taken over by prepaid billing system can be
understood by the below flowchart:
Fig 1:Flowchart for prepaid electricity billing system

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3.1 The Main Advantages of this Method are:
 It is highly accurate as the whole idea of reading the units and then billing manually or
any other means is eliminated.
 Consumer cannot escape from paying the electricity bill and the State Electricity Board
gets free from debts.
 On the consumer front, the tedious task of paying the bill and waiting anxiously for the
bill is eliminated.
 Wastage of energy is diminished as now only the required energy will be consumed as
allotted.
 The power grid can monitor the overall energy consumption and any tampering
attempts are actually of no use and can be detected if still prevalent.
The warning message for next recharging of electricity is sent to customer after decreasing the
balance of customer beyond the threshold amount of power. Now you are thinking that
someone can use the electricity from his neighbor by connecting his service line to his
neighbor’s service line. Yes it can be happened, the utility can identify the thief. Also the
amount power decreased from the account of customer is only that the customer consume.
The electricity consumed by thief is added in its upper hierarchical level element. The server
Continuously checks the consumption account of customer and delivered power accounts of
transmission and distribution elements. If the sum of power consumed from the same level of
element is not match with power delivered by its upper level element, the utility knows that the
electricity is being theft by someone. It can easily identify the tempered area and can take
require legal action.
3.2 PREPAID ENERGYMETER
Working of a prepaid energymeter:
The prepaid card is recharged for a certain amount and can be fed as input to the
Microcontroller AT89S52. The AT89S52 is programmed such that power supply will be
switched off by using relay when the rechargedamount get used up. The GSM communication
module is used to send a message to the consumer about the units of power consumed and their
balance and also LCD display is used to display the balance amount.

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Fig 2: GENERAL BLOCK DIAGRAM
LabVIEW Simulation:
Logic is created that varies the power consumption according to the usage of load, so under no
load, there is no power consumption and no reduction in the price that is recharged. Algorithm
used in labVIEW is given below: Insert the card into the Programmer (here the variable is used
to represent the recharge amount). Unit price per watt is multiplied with the consumed unit to
give the current bill. The current bill amount is the deducted from the recharged amount. When
the total amount recharged is used up, and then the power supplied to the load is stopped.

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Fig 3: SIMULATION MODEL UNDER NO LOAD CONDITION(no rotation of motor takes
place)
In the above simulation the concept of decoder with 3 inputs is used and instead of energy
meter multimeter was used. Similarly the simulation is designed for all the eight combinations
of input and the output voltage is varied.

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Fig 4: SIMULATION MODEL UNDER LOADED CONDITION(the motor rotates
proportionally to the power consumption)
In the above simulation initially the amount to be recharged is entered and according to the
output of the proximity sensor (unit consumption) total amount is kept reduced till it is used up
and by then the loop is terminated.

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Fig 5: SIMULATION MODEL FOR MONITORING THE POWER CONSUMPTION
Working (internally):
The Microcontroller AT89S52 acts as the primary controller. The primary controller collects
information from energy meter as well as from the smart card. Here, switches are used instead
of the IC. Smart card, which is the switch, gives information about the limitation of units. The
energy meter reading is compared with the smart card information by the microcontroller.
Depending upon the result, the microcontroller will activate the buzzer if the credit is low and
the Controller will trigger the Relay if the credit goes very low. The relay is the switching
device to cut off and restore power supply. The LCD is interfaced to microcontroller using
parallel port connection. The microcontroller based system, continuously records the readings.
The coding emphasizes the fact that it reduces human labour but increases the efficiency in
calculation of bills for used electricity.The user can be notified about the low balance in their
credit with the help of the GSM module. The GSM modem is serially connected with the
controller which is the major communication module between user and meter. The GSM uses
its own network for the transfer of information. The programming makes use of messaging
features of GSM AT command. And, once the relay is triggered, the electricity supply will be
cut off. The power will be supplied again only if the meter is recharged with enough credit.

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Fig 6 : CIRCUIT DIAGRAM OF PREPAID ENERGYMETER
To the above diagram GSM technology is included to send messages to the customer about the
balance amount and if the amount is totally used up then we shut down the power after alerting
user.

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Chapter 4
OTHER MODELS OF ENERGYMETER
Some of the other models of prepaid energymeter have two memory storage places for
temporary storage in simple form as below:
Simple Prepaid Energy Meter Kit:
A simplest type of prepaid energy meter consists of 2 EEPROMs interfaced to a
microcontroller. One EEPROM contains the recharged balance amount. The microcontroller
reads this balance and stores it in the other EEPROM along with the tariff.
The energy meter supplies pulses to the microcontroller for every unit of energy consumed.
The microcontroller increases the spent energy unit by one and decreases the balance amount
in the EEPROM by the fixed tariff. As soon as the balance amount in the EEPROM comes
down to zero, the microcontroller sends a signal to the relay driver which in turn switches off
the relay, such that the main supply to the load is switched off. An LCD is also interfaced to
the microcontroller which displays the amount of energy consumed.
Fig 7: Working block diagram for prepaid energymeter

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The recharge card is actually an EEPROM in which the balance amount along with the
allocated energy units is stored. The Microcontroller reads the balance amount and stores it
along with the tariff and the energy units allocated in its RAM and are programmed to delete
off the information present in the EEPROM (making the card invalid for further use). The
energy meter gives electric signal to the opto isolator which consists of an LED and an opto-
transistor combination such that the LED glows and emits light for every electric signal
received by the energy meter (which sends a electric signal for every unit consumed). The opto-
transistor starts conducting and sends high and low pulses to the microcontroller. The
microcontroller is programmed such that a counter is kept incrementing for every pulse rate,
which gives the value of the energy consumed.
Another EEPROM is interfaced to the microcontroller where the balanced amount and the
energy units consumed are stored. For every increment in count, the balanced amount in this
EEPROM is deducted. Finally when the balance amount is zero, the microcontroller sends a
low signal to the Relay driver to give a high signal at its output, which switches off the relay.
Normally the microcontroller gives a high signal to the input pin of the relay driver, which
develops a logic low signal at its corresponding output pin and the relay coil is energized, thus
connecting the load to the main supply.
Practical Prepaid Energy Meters:
Fig 8: Prepaid Energymeter with a card

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Fig 9: Prepaid energy meter for which a key is used in place of a card
It is a 3 in 1 dual source meter. It also monitors water and gas consumption along with electrical
consumption. All the consumer has to do is to display the card in the front panel of the meter
for a time of 3 seconds. The microcontroller stores the number of units allocated and measures
the energy consumed. This system automatically switches off the power supply once purchased
units are used up. Its applications include shopping malls, residential townships, commercial
buildings, employee quarters etc.
To get a meter reading from your prepayment meter, you will usually have to press a button on
the meter. This will change the display from showing the remaining credit to showing the actual
reading. From there on, it's just like taking a normal meter reading.
4.1 PROS AND CONS OF PREPAID ENERGYMETER:
When it comes to prepayment meters, the disadvantages generally outweigh the advantages.
Advantages of prepayment meters include:
 helping customers to manage their debt and energy usage;
 preventing large, unexpected bills.

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Disadvantages of prepayment meters include:
 above average costs for your gas and electricity;
 the best energy deals on the market aren't available to prepayment meter customers;
 they can be inconvenient because you have to go out to 'top up' keys and smartcards;
 if you can't reach a shop to top up your meter your energy can be switched off;
 older meters need to have their prices updated manually after price rises or falls, which
can take months. This means you could be left paying old rates and owing a lump sum
or paying too much.
Besides the salient features of this prepaid energymeter are as follows:
 Compact wall mounting design
 Optional remote display unit
 Accuracy Class 1.0 IS13779
 Dual Source Measurement (EB & DG)
 Current Limiting facility for DG
 Advanced contact-less encrypted RF card technology
 Optional Gas and Water measurements
 Money based recharging, No separate EB and DG recharging
 Each smart card is tagged to the meter to prevent misuse
 Measures kWh from dual source like EB and DG
 Field programmable trip facility when the alternate source trips
 Overloading / Tripping of DG is prevented due to excess drawing of power by
consumers
 Reconnects automatically after programmable delay time
 External current limiters not required

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Chapter 5
CONCLUSION
The paper is intended to present an overview of prepaid energy meter, which can control the
usage of electricity on consumer side to avoid wastage of power. Prepaid energy meter is a
concept to minimize the Electricity theft with a cost efficient manner. The design of Smart
Energy meter using GSM technology can make the users to pay for the electricity before its
consumption. In this way, consumers hold credit and then use the electricity until the credit is
exhausted. If the available credit is exhausted then the electricity supply is cutoff by a relay.
An arrangement is also made to intimate the user with the help of GSM communication module
when their credit in their balance goes low. This system has been proposed as an innovative
solution to the problem of affordability in utilities system. Since a microcontroller based system
is being designed, the readings can be continuously recorded. This reduces human labour and
at the same time increases the efficiency in calculation of bills for used electricity. Smart energy
meters will bring a solution of creating awareness on unnecessary wastage of power and will
tend to reduce wastage of power. This module will reduce the burden of energy providing by
establishing the connection easily and no theft of power will take place.
1. The users are not bound to pay excesses amount of money, users have to pay
according to their requirement.
2. It can reduce problems associated with billing consumers living in isolated areas
and reduce deployment of manpower for taking meter readings.
3. Prepaid energy meter is more reliable and user friendly.
From all these we can conclude that if we implement this prepaid energy meter then it can
become more beneficial.
REFERENCES
[1] NTP C D Employees Reading material eng,
http://www.Frecindia.nic.in/download/NTP_C&D_Employees_Reading_Material_eng.pdf
[2] Client/Server Software Architectures: An Overview, Carnegie Mellon Software
Engineering Institute, http://www.sei.cmu.edu/str/descriptions/clientserve r_body.html
[3] Three Tier Software Architectures, Carnegie Mellon Software Engineering Institute,
http://www.sei.cmu.edu/str/descriptions/threetier.html#34492