Power Theft Detection
1. INTRODUCTION The automatic meter reading(AMR) system as become a necessity for most suppliers as deregulation, free customer choice and open market competition occur in the energy supply sector. Power line communication has many new service possibilities on the data transferring via power lines without use extra cables.
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AMR is a very important application in these possibilities due to every user connected each other via modems using power lines. AMR is a technique to facilitate remote readings energy consumption.
Improving the electrical power supply to households as a big issue. The government has set a specific goal to raise the distribution rate of electrical power supply, which is now around 70% to 80% to 100%. Power companies are plagued by power theft. PLC will play an important role in placing anti-theft power system. Illegal electricity may be a serious problem in many countries . This problem has been attempted to be resolved by special skills of humans, such as the police special security etc. These method could not give optimum solution due to their impracticalities.
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Meter reading has been applied by humans and some electronics solutions such as optical reading methods, creditable utilization of electrical energy etc. Many chips which can be used for digital energy metering and PLC modems. The problem of illegal usage of electricity must be solved electronically, without any human control. 2. POWER THEFT 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 theday 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. The fraudster risks electrocution and detection. Field employees of the power company are trained to spot problems that result in persons not being billed for all the electricity they use. Computerized billing systems are designed to detect erratic electricity use Fig No 2. 1 3. PLC installATION.
Power meters with PLC modules will be installed near the top of the power polls. Previously, it was enough to install power meters in high places, not in low places such as the house wall, to prevent users from using power illegally by connecting cables, or by using tampered meters. However, by doing so, the homeowners themselves cannot check how much electricity was used. Therefore, PLC technology was chosen. 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. [pic] Fig No3. 1 • 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 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.
In this way, HD-PLC and optical fiber networks enable power companies to prevent power theft, and to grasp the actual amount of power consumed by district or by each household in real time, and also to control the amount of power supply. 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’. 4 . DETECTION OF ILLEGAL ELECTRICITY USAGE 4. 1 Methods Of Illegal Electricity Usage:
In illegal usage, a subscriber illegally use electricity in following ways: 4. 1. 1 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. 4. 1. 2 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. 4. 1. 3. Using the external phase before meter terminals: This method gives subscribers free energy without any record. . 1. 4. 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. 5. DESCRIPTION ON PLC Most economically viable technology for transferring Meter data to DCU. Uses the technique of communicating the data over existing Electrical Lines which carry LT power to the site.
PLC is a kind of communication technology, which uses Medium Voltage(MV) and Low Voltage(LV) distribution network as the communication media to implement transmission of data, voice and real time image. The components involved in PLC are the; 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 5. 1 The monitoring system mainly has the following functions: 1. Remote meter-reading 2. Data acquisition 3. 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 ? s. Square wave with a max Delay of 100 ? s from the zero crossing point The maximum delay between signal envelope input and 120KHz output bursts is 50 ? s. Therefore, it should be arranged that outputs to the within 50 ? s. 5. 2 CODE TRANSMISSION: 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. 6. DIFFERENT COUPLING UNITS. [pic] 7. DEFINITION ON AMR AMR(AUTOMATIC REMOTE READING) 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. 7. 1 ADVANTAGES: 1. Smart automated process instead of manual work. 2. Accurate information from the network load to optimise maintenance and investments . 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. 8. DETECTION AND CONTROL SYSTEM The proposed control system for the detection of illegal electricity usage is: [pic] FIG. 8. 1 PLC signaling is only valid over the low voltage -220VAC power lines. The system should be applied to every low-voltage distribution network.
The system given in fig 7. 1 belongs only one distribution transformer network and should be repeated for every distribution network. Although the proposed system can be used uniquely, it is better to use it with automatic meter reading system. If the AMR system will be used in any network, the host PLC unit and a PLC modem for every subscriber should be contained in this system. In fig7. 1 the host PLC unit and other PLC modems are named PLC1A,…. ,PLCNA and are used for AMR. These units provide communication with each other and send the recorded data in kilowatthour meters to the PLC unit.
In order to detect illegal usage of electrical energy, a PLC modem and an energy meter chip for every subscriber are added to an existing AMR system. As given in fig1, PLC1B,……,PLCNB and energy meter chips belong to the detector. The detector PLC’s and energy meters must be placed at the connection point between distribution main lines and subscriber’s line. 8. 1 ADVANTAGE OF THIS SYSTEM : Most economically viable technology for transferring Meter data to DCU. Uses the technique of communicating the data over existing Electrical Lines which carry LT power to the site.
Since the connection point is usually in the air or at underground, it is not suitable for anyone to access, such that its control is easy. It is very economical and is reliable solution when it is compared with the economical loss caused by illegal usage. 8. 2 CONDITIONS FOR THIS DETECTION AND CONTROL: PLC signaling must be in CENELAC standards. CENELAC has formed the standard in which the frequency bands, signaling levels, and procedure are specified. 3-9 khz are restricted for use by electricity suppliers, and 95-148. 5khz are restricted to consumer use. The signal level for the band 95-148. khz is limited as follows. For general use ,the signaling level is limited to 116dbµV. 9. DETECTION The recorded data in kilowatt hour meters for every subscriber are sent to host PLC modem via PLC modems which are placed in subscribers locations. On the other hand energy meter chips are located in connection point and read the enrgy in kilowatthours and also send the data to host PLC unit. This proposed detector system as two recorded energy data in host PLC unit, one which comes from the AMR-PLC, and the other which comes from the PLC 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. This means that there is an illegal electricity usage in the network. After that, the subscriber address and error signal are combined and sent to the central control unit. If it is, requested, a contacter may be included to the system at location to turn off the energy automatically, as in the case of illegal usage 10.. ILLEGAL DETECTOR SYSTEM FOR ONE SUBSCRIBER [pic] Fig No 10. 1 11.
SYSTEM SIMULATION AND MODELLING OF THE DETECTION SYSTEM OF ILLEGAL ELECTRICITY USAGE FOR ELECTROMECHANICAL KILOWATTHOUR METERS [pic] Figure 11. 1 A host PLC modem, an energy meter chip and its PLC modem, an electromechanical kilowatthour meter and its PLC modem, and an optical reflector sensor system are loaded at the same phase of the power grid. The energy value at the electromechanical kilowatthour meter is converted to digital data using optical reflector sensor. Disk speed of the kilowatthour meter is couted and obtained data is sent to PLC modem as energy value of the kilowatthour meter.
At the system model, an illegal load may be connected to the power line before the kilowatthour meter via an S switch. While only a legal load is 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. If the S switch is closed ,illegal load is connected to the system. , and therefore two recorded energy values are different from each other. The host PLC unit is generated when it received two different records from the same subscriber. This is the detection of the illegal usage for interested users.
In these, the tests, the carrier frequency is selected at 132khz, which is permitted in the CENELAC frequency band. In real application, the AMR system may be designed in all CENELAC bands. The data rate between the host and the other PLC modem is 2400b/s. 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 and national power grid architecture.
In the digital energy meter system, the recorded energy may be received in the digital form directly using the port of the meter. Therefore, there is no need for an optical reflector system in digital meters. 12. AN OVERVIEW OF THE PROPOSED DETECTOR SYSTEM The proposed detector system is the equipment and procedure for controlling more remote stations from a master control station. It includes PLC modems, energy meters, control logics, and the system software . 12. 1 PLC MODEMS: These used for two way communication to and from the host station and the remotely controlled targets. 12. 2 ENERGY METER AND CONTROL LOGIC:
Energy meter includes metering chip, and some circuit element. control and logic units compare and generate the error signal in the illegal usage. 12. 3 SYTEM SOFTWARE: Assembler program for the microcontroller and the operating software for the management of the overall system. Operator software may be downloaded from a PC and should be placed in the main center of the system. 13. AN AMR SYSTEM FOR AN ILLEGAL DETECTOR PERFORMS THE FOLLOWING FUNCTONS: 1) 1Every user has two PLC modems; one is for AMR and the other is used to send the data from second energy meter chip to host PLC modem. ) An energy meter must be connected in the connection box between a home line and main power lines. 3) The host PLC unit must be placed in the distribution transformer and the configuration of the addressing format of PLC signaling must be designed carefully. 4. The host PLC modem and its controller must include two addresses per every user: one is the AMR and the other for the energy meter. These two addresses must be selected sequentially. 5. Operating software must designed for the information of every subscriber in every sub power network: subscriber identification number, billing address etc. . The system has two values of energy consumption for every user, so if there is a difference between them an error signal is generated for the illegal user. 7. The proposed equipment is the only one distributed in the power network. So this system should be repeated for all distribution power networks. All host units in each distribution transformer maybe connected only one main center station via phone lines, fibre optic cable or RF links. 14. CONCLUSION A detector system to determine illegal electricity usage via power line communication is designed and proposed.
The proposed system is examined in laboratory conditions. Obtained results from this study show that if the AMR and detector system are used together, illegal usage of electricity may detected. The system functions with real-time monitoring users and burden forecast, which uses MV&LV PLC as its transmission media. The system is integrated with power management and burden control. Under power theft, the relay is switched off isolating the area of power theft from the EB side . LCD display also indicates power theft. Energy regulation does not epresent an obstacle, since PLC service does not affect the power supply and maintains separate accounts from the core utility business. Once this proposed system is tried in real power lines, the distribution losses can be reduced effectively. 15. REFERENCE Hakki Cavdar, ”A solution to remote detection of illegal electricity usage via power line communication”, IEEE Trans. Power Delivery,vol. 19,no. 4,Oct 2004.  T. Y. Lim and T. W. Chan, “Experimenting remote kilowatt hour meter through low voltage power lines at dense housing areas”, IEEE Trans. Power Delivery, vol. 17, pp708-711,july 2002.  J.
Newbury and W. Miller,” Multiprotocol routing for automatic remote using power line carrier systems”, IEEE Trans. Power delivery,vol. 16 pp 1-5,Jan 2001. ABSTARCT Power Line Communication (PLC) presents an interesting and economical solution for automatic meter reading (AMR). If an AMR system via PLC is set in a power delivery system, a detection system for illegal electricity usage may be easily added in the existing PLC network. In the detection system, the second digitally energy meter chip is used and the value of energy is stored. The recorded energy is compared with the value at the main kilowatt-hour meter.
In the case of difference between two recorded energy data, in error signal is generated and transmitted via PLC network. The detector and control system is proposed. The architecture of the system and their critical components are given. This report describes a prototype of the detector system for illegal electricity usage using the power lines. ACKNOWLEDGEMENT I am thankful to Prof. Sukumaran P R ,Head of the Department for providing me with the facilities for the seminar. I would also express my sincere gratitude to Mrs. Rajashree Raghavan ,for her guidance and mere cooperation for preparing and presenting the seminar.
Above all I thank all the faculties of the EEE Department and my friends for their moral support and encouragement. CONTENTS 1. INTRODUCTION01 2. WHAT IS POWER THEFT? 02 3. How is PLC installed ? 03 4. DETECTION OF ILLEGAL ELECTRICITY USAGE04 5. DESCRIPTION ON PLC:05 6. DETECTION AND CONTROL SYSTEM07 7. ILLEGAL DETECTOR SYSTEM FOR ONE SUBSCRIBER:10 8. SYSTEM SIMULATION AND MODELLING OF THE DETECTION SYSTEM OF ILLEGAL ELECTRICITY USAGE FOR ELECTROMECHANICAL KILOWATTHOUR METERS11 9. AN OVERVIEW OF THE PROPOSED DETECTOR SYSTEM:13 10. CONCLUSION:15 11. REFERENCE16