Power Theft Detection via PLC

By,Shashanka B (1RV08EE047)Ravi S Gokavi (1RV08EE041)Chandrashekar C (1RV07EE016)

Electrical power by altering, slowing, resetting, swapping, or disconnecting an electric meter.

Theft also may occur by rewiring circuits to avoid an electric meter, or by tapping into another customer’s electrical lines.

The fraudster might use devices to program the theft of power only during certain periods of the day or week.

A fraudster may rewire their property to illegally use power from cheaper sources of power, or from meters that are billed at lower rates.

To minimize power theft PLC’s can be installed.

POWER THEFT

It is a digital computer used for automation of electromechanical process.

The PLC’s are designed for multiple input and multiple output.

Program to control machine operation are typically stored in non volatile memory.

It is an example of a hard real time system since output results must be produced in response to input conditions within bounded time.

PLC (Programmable logic controller)

Seimens Simatic S7-400

Early PLC’s were programmed by using specific purpose programming terminals.

The programs were stored in cassette tape cartridges.

Facilities of printing and documentation were very minimal due to the lack of memory.

The very old PLC used non-volatile magnetic core memory.

Programming of PLC

Recent PLC’s are programmed using application software's on personal computers.

Computer is connected to PLC through RS-232, RS-485 or RS-422.

The software provides the facilities of debugging and troubleshooting the PLC software.

Modern PLC’s use EEPROM or EPROM as a memory.

Continued…..

Programming of PLC

Oldest PLC by BEDFORD ASSOCIATES

Modern PLC’s

The main difference from other is that PLC’s are armored for severe conditions and have the facilities for extensive I/O arrangements.

It can be connected to sensors, actuators. They also read limit switches and analog

process variables. They can operate electrical motors,

pneumatic or hydraulic cylinders, magnetic relays etc.

PLC features

Control panel with PLC

Power meters with PLC modules will be installed near the top of the power polls.

Meters installed in high places will send data of the used amount to each household through power lines.

Homeowners can then check the amount used on the displays installed in each house.

This means that the measurement function and the display function of the meters will be separated.

Power theft is prevented by installing HD-PLC-mounted power meters on a high position on power polls, while the amount of power used in each household can still be checked.

PLC INSTALLATION

Each power meter is connected to an optical fiber network, and information of the amount used by each household is sent to the power companies.

If the power companies find that a payment is delinquent, they can remotely stop the power supply by controlling the meters through the optical fiber network.

The waste of power can also be reduced, another big advantage.

Furthermore, wide spread use of the power meters with HD-PLC modules is expected to reduce regional disparities in information, or the ‘digital divide’.

Installation of PLC

Using the mechanical objects:A subscriber can use some mechanical objects to prevent

the revolution of a meter, so that disk speed is reduced and the recorded energy is also reduced.

Using a fixed magnet: A subscriber can use a fixed magnet to change the

electromagnetic field of the current coils. As is well known , the recorded energy proportional to electromagnetic field.Using the external phase before meter terminals: 

This method gives subscribers free energy without any record.Switching the energy cables at the meter connector box:

In this way ,the current does not pass through the current coil of the meter, so the meter does not record the energy consumption.

Although all of the methods explained above may be valid for electromechanical meters, only the last two methods are valid for digital meters.

Methods Of Illegal Electricity Usage

1. Power Line Carrier Unit which provides signal transmission and reception.

2. There is a Coupler used for “clamping” around a live wire thus injecting the communication signals into the power line.

3. PLC modem

The components involved in PLC are,

1. Remote meter-reading2. Data acquisition3. Thread PLC transmissions are synchronized to

the zero crossing point of the AC power line.

It should be transmitted as close to the zero crossing point i.e. within 200 μs. Square wave with a max Delay of 100 μs from the zero crossing point The maximum delay between signal envelope input and 120KHz output bursts is 50 μs. Therefore, it should be arranged that outputs to the within 50 μs.

The monitoring system mainly has the following functions

A Binary 1 is represented by a 1 ms burst of 120 KHz.

The zero crossing point and a Binary 0 by the absence of 120 KHz.

Therefore only the 1 ms "envelope" need be applied to their inputs.

These 1 millisecond bursts should actually be transmitted three times to coincide with the zero crossing points of all three phases in a three phase distribution system.

CODE TRANSMISSION

Automates the process of measurement through digital communication techniques.

Bring “intelligence” into the revenue cycle and manage it.

The revenue cycle includes metering, billing operating, customer and the services.

DEFINITION ON AMRAMR(AUTOMATIC REMOTE READING)

1. Smart automated process instead of manual work.2. Accurate information from the network load to

optimise maintenance and investments.3. Customized rates and billing dates.4. Streamlined high bill investigations.5. Detection of tampering of Meters.6. Accurate measurement of transmission losses.7. Better network performance and cost efficiency.8. Demand and distribution management.9. More intelligence to business planning.10.Better company credibility.

ADVANTAGES

VIPA art of Automation Unikom-Ug – metering Alstom ABB utility communications ADD group Motorola Delta PLC

Etc……

Companies manufacturing PLC’s

THANK YOU