An application of PLC- Remote Detection of illegal usage of Electricity

By :

Sujit Kr. Nayak

ecTech

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Plan of the Talk…

Introduction to PLC

Idea about AMR

Methods of illegal usage of Electricity

The detection system

System Review

Conclusion

References

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Introduction to PLC

Power Line Communication (PLC) is the technique in

which the communication is takes place over the same

line that deliver electricity.

In this technique, a high frequency carrier is injected

onto the power line.

The data to be sent is modulated with the injected

carrier.

It has a wide range of application possibilities. Automatic

Meter Reading (AMR) is an important among all.

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Automatic Meter Reading (AMR)

AMR a very useful application of PLC.

This provides remote recording of usage of

electricity of an user.

The reading of the Meter is translated into

digital form in order to send the metering data

from the user to a Base station.

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Contd…(AMR)

Incident Ray

Reflected Ray

Optical Sensor

Digital Signal

Output

Marker

Rotating Disc in

Meter Housing

Fig: Electromechanical movements to Digital signal Converter

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Contd…(AMR)

The Digital metering data is send to the Base

station using PLC modems.

The Base station unit consists of Modems,

Receivers, Data Concentrators, Controller,

Host upload link, and Host Computer.

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AMR system setup…

BASE

STATIONMODEM MODEM METER

MODEM METER

Fig: AMR communication setup

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Methods of illegal usage of electricity

Using Mechanical Objects

Using a fixed Magnet

Using external phase before the meter

Switching the energy cable at meter

connector box

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The Detection & Control System…

Fig: Schematic illustration of detection system of illegal electricity usage

Distribution

Transformer

Host PLC

PLC

kWh

PLC

To Control Center

220v AC

Energy

Meter

Subscriber 1 Subscriber 2

Subscriber N

PLC

kWh

PLC

Energy

Meter

PLCEnergy

Meter

PLC

kWh

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The Detection & Control System…

In order to detect illegal usage of electricity, a PLC modem and an energy meter chip for every subscriber are added to an existing AMR system.

The detector PLC s and energy meters is placed at the connection point between distribution main lines and subscriber’s line.

The recorded data in kilowatt-hour meters for every subscriber are sent to host PLC modem via PLC modems, which is placed in subscriber’s locations.

On the other hand, energy meter chips reads the energy in kilowatt-hours and also send the data to host PLC unit.

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The Detection & Control System…

Hence, there are two recorded energy data in host

PLC unit, one, which comes from the AMR-PLC,

and the other, which comes from the PLC modem at

the connection points.

These two recorded energy data are compared in

the host PLC. If there is any difference between two

readings, an error signal is generated (i.e. There is

an illegal usage ). Then the subscriber address and

error signal are combined and sent to the central

control unit.

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The Detection & Control System…

X Subscriber

PLC

ModemEnergy meter chip

PLC

Modem

kWh

Meter

Host

PLC

Modem

uP Logic

To control center

Connector Box for X Subscriber

Host PLC unit

Main

po

wer

lin

e

220 V

AC

Fig: Illegal detector

system for one

subscriber

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Working of the System…

HOST

PLC

MODEM

L

PLCOptical

Sensor

PLCEnergy

Meter

I.L

KWh Meter

S

Power Line

Disk

Fig: Modeling of the detection system

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Working of the System…

The energy value at the electromechanical kilowatt-

hour meter is converted to digital data using by

optical reflector sensor.

An illegal load may be connected to the power line

before the kilowatt-hour meter via an S switch.

While only for a legal load in the system, two meters

are accorded each other to compensate for any

error readings. The host PLC unit reads two

recorded data coming from metering PLC units.

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Working of the System…

If the S switch is closed, the illegal load is

connected to the system, and therefore two

recorded energy values are different from

each other.

The host PLC unit generate a error signal

when it received two different records from

the same subscriber. This is the detection of

the illegal usage of that user.

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Working of the System…

Data signaling between PLC modems has a

protocol, which includes a header, address,

energy value data, error correction bits, and

other serial communication bits such as parity

and stop bits. The protocol may also be

changed according to the properties of the

required system

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Parameters on which the system depends

The relations between frequency, length, and bit-error probability are

given in these figures shown.

Fig: Effect of frequency on Bit Error rate Fig: Effect of line length (meters) on Bit-error probability

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System Review…

Every user has two PLC modems; one is for AMR and the other is used to send the data from energy meter chip to host PLC modem.

The energy meter must be installed in the connection box between a home line and main power lines.

The host PLC unit must be placed after the distribution transformer.

Operating software must be designed for the information of every subscriber in every sub power network (subscriber identification number, billing address etc).

The system has two values of the energy consumption for every user, if these two values are different, the user is an illegal one.

The discussed system is for only one distributed power network and it should be repeated for all distribution power networks.

All host units in each distribution transformer may be connected to only one main center station via phone lines, fiber-optic cable, or RF links.

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System Limitations….

It can not be used at high voltage power

lines.

It is unable to detect any illegal load

connected in between the distribution

transformer and the energy meter.

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Conclusion…

If AMR and detector system are used

together illegal usage of electricity might be

detected.

Once this proposed detection systems are

implemented in real power lines, the

distribution losses in India can be reduced

effectively.

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References…

I. H. Cavdar, “A Solution to Remote Detection of Illegal Electricity

Usage via Power Line Communications”, IEEE Transactions On Power Delivery,

Vol. 19, No. 4, October 2004.

Agustín Zaballos, Alex Vallejo, Marta Majoral, and Josep M. Selga,

“Survey and Performance Comparison of AMR Over PLC

Standards”, IEEE Transactions On Power Delivery, Vol. 24, No. 2, April 2009.

I. H. Cavdar, “Performance analysis of FSK power line

communications systems over the time-varying channels:

Measurements and modeling”, IEEE Trans. Power Delivery, vol. 19, pp. 111–117, Jan.

2004.

N. Miura, H. Sato, H. Narita, and M. Takaki, “Automatic meter

reading system by power line carrier communications”, IEE Proceedings,

Vol. 137, Pt. C, No. I , January 1990.

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Thank U…