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TABLE OF CONTENTS
1 Introduction: ................................................................................................................................2
2 Background:................................................................................................................................2
3 Normal Meter Working: ................................................................................................................2
4 Tampering methods:....................................................................................................................3
4.1 Neutral current reverse: ........................................................................................................3
4.2 Phase current reverse: .........................................................................................................3
4.3 Phase and neutral current reverse:........................................................................................4
4.4 Current bypass: ...................................................................................................................4
4.5 Open meter: ........................................................................................................................4
5 Solutions employed by PEL:.........................................................................................................4
5.1 Introduce PT: .......................................................................................................................5
5.1.1 Neutral Current reverse solution: ...................................................................................5
5.1.2 Phase current reverse solution: .....................................................................................5
5.1.3 Phase and neutral current reverse solution: ....................................................................5
5.1.4 Current bypass solution:................................................................................................5
5.2 Fault indicating LED: ............................................................................................................5
5.3 Push button: ........................................................................................................................5
6 Conclusion: .................................................................................................................................6
7 References: ................................................................................................................................6

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INTRODUCTION:
An electricity meter, electric meter, electrical meter, or energy meter is a device that measures the
amount of electric energy consumed by a residence, a business, or an electrically powered device.
Electric utilities use electric meters installed at customers' premises to measure electric energy
delivered to their customers for billing purposes. They are typically calibrated in billing units, the most
common one being the kilowatt hour [kWh]. They are usually read once each billing period.
When energy savings during certain periods are desired, some meters may measure demand, the
maximum use of power in some interval. "Time of day" metering allows electric rates to be changed during
a day to record usage during peak high-cost periods and off-peak, lower-cost, periods. Also, in some areas
meters have relays for demand response load shedding during peak load periods.
BACKGROUND:
Electricity theft is not a new problem. In Pakistan, non-technical losses caused by electricity theft
can be as high as 20% of the generated energy delivered to the distribution network. All over the world,
electricity theft is a big problem. This scenario is not restricted to underdeveloped countries, the percentage
varies and occurs in almost all countries. Among the usual fraud techniques are illegal tap wiring and meter
tampering through security seal violations. These frauds are detected by periodical line inspections and
fraud evidences are easily found and then solved by the companies.
Energy providers are constantly challenged to uncover new fraud techniques developed by creative
people, for example, tilting the electromagnetic meter, directly taking supply from transmission line. Fraud
techniques keep evolving electronic meter with bi-directional communication provides new vulnerabilities
to interconnected systems. New subtle fraud techniques are surprisingly refined by the knowledge applied
to energy stealing as well as the amount of damages. These facts pose high level countermeasures and
systematic forensics investigation for detecting fraud and evidence gathering.
NORMAL METER WORKING:
To measure the power utilized by load, current (I), voltage (V) and their phase difference (θ) are
measured in a meter. In single phase meter, Current flow starts from Phase input (Pin) of the meter, then it
flows from Shunt, where the amount of current (I) is measured, and the voltage (V) is measured by the
voltage difference between live wire and neutral. Now, we have voltage and current, so Phase angle (θ) is
measured by following formula: θ = θv - θi and hence, power utilized is measured by following formula:
P=VIcosθ, which is displayed on LCD.

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Figur e 1 Nor m al Single Phas e M e te r
TAMPERING METHODS:
Neutral current reverse:
In neutral current reverse method, Neutral is externally grounded, and the meter is tempered by
following mechanism: current flows from Pin to shunt where current (I) can be measured but now neutral
is externally grounded so voltage can’t be measured and hence phase angle can’t be measured. So,
Power can’t be determined and the meter doesn’t show any power utilized.
Figur e 2 Ne utr al te m pe r ing
Phase current reverse:
In this method Phase is externally connected to Load so, current doesn’t pass from shunt and hence
current can’t be measured i.e. power can’t be determined. And the meter will not display any power utilized.
Figur e 3 Phas e tam pe r ing

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Phase and neutral current reverse:
In this method of tempering, Current is supplied directly from phase input of the meter to load, and the
load is externally grounded. So current doesn’t pass from shunt i.e. current can’t be measured. Moreover,
since load is externally grounded so there is no reference point to measure voltage so voltage can also not
be measured and eventually power can’t be determined, so meter will not display power consumed.
Figur e 4 Phas e and ne utr al tam pe r ing
Current bypass:
In this method, current is bypassed from phase input to phase out, now the current will not pass through
the shunt i.e. amount of current supplied to load can’t be measured and hence power can’t be measured
and the meter will not show power consumed by load.
Figur e 5 Cur r e nt bypas s tam pe r ing
Open meter:
Meter can be tempered by open it’s lid and changing the internal circuit.
SOLUTIONS EMPLOYED BY PEL:
To stop these methods of tampering PEL employed several methods:
1) Introduce PT
2) Fault indicating LED
3) Push Button

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Introduce PT:
PEL introduced potential transformer (PT) in their meters as shown in the figure:
Figur e 6 PT and CT
NEUTRAL CURRENT REVERSE SOLUTION:
In neutral current reverse method, load is externally ground, so voltage can’t be measured
i.e. power can’t be measured. After CT and PT was introduced in meters, now when neutral is
externally ground, current flow starts from Pin then it flow to shunt where amount of current (I) is
measured, then it passes to PT producing magnetic flux, then it flows from load to ground. The
magnetic flux produced energizes the PCB, and meter use default 220V and power factor 1 and
measure the power and will be displayed on LCD.
PHASE CURRENT REVERSE SOLUTION:
In phase current reverse, phase input is directly connected to load, now we can’t measure
current, but voltage can be measured by potential difference between phase and neutral wire. So
dividing this voltage with value of shunt current is also determined with phase angle 0° and hence
power is determined using these values.
PHASE AND NEUTRAL CURRENT REVERSE SOLUTION:
There is no method introduced so far to rectify this method of tampering.
CURRENT BYPASS SOLUTION:
This method is rectified by dividing the obtained voltage with value of shunt resistance to
obtain the amount of current and hence power is calculated.
Fault indicating LED:
Whenever the meter is tempered by any of the above method fault LED turns on to indicated that meter
is tempered so line man can resolve this issue
Push button:
PEL introduced bush buttons in their meter which is in ON state. Now, when meter is opened for
tempering purpose, push button gets in OFF state and meter display OPEN on LCD for permanent until
rectified by PEL.

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CONCLUSION:
This report is prepared for academic purpose and this report is highlighting the method of tampering
used by the costumers and their remedies. Apart from that, some other above tampering methods are
mentioned which will be resolved with time.
REFERENCES:
The idea of theft and its removal is taken from the below lik
[1]"Tampering Methods of Energy Meter", Electrical Notes & Articles, 2011. [Online]. Available:
https://electricalnotes.wordpress.com/2011/06/08/tampering-methods-of-energy-meter/. [Accessed:
24- Jun- 2016].