Power Theft Prevention In Distribution System Using Smart Devices

Power theft is one of the major issues of electricity transmission and distribution. It is prominent in developing countries and pilots to an annual losses of around INR 3000 crores in India. It is estimated that power theft accounts to 1.5% of Gross Domestic Production (GDP) which is significant and cannot be negligible. Power theft prevention is a system used to perceive and prevent illegal load tappings on distribution lines. Many schemes are available for the same and a scheme using smart electric devices employing electronic energy meter is used in this paper. A real time comparison method is used to compare the current at L.V (low voltage) side of the distribution transformer with that of the consumption of connected legal consumers. A wireless zigbee module is employed for this purpose. An automatic control unit is used to inject frequency disturbances in L.V lines, after disconnecting the legal consumers’ loads once power theft is detected. A simple design for single phase distribution system is proposed for analysis and same can be implemented for three phase system by adding relevant features.

There is a huge demand for electricity and there is always a mismatch between supply and demand. Satisfactory operation of power systems requires overall coordination of all the power system components. Attention and focus are given for generating power using both renewable and conventional sources of energy. But the transmission of power also plays a vital role in conveying power with minimal loss to the consumers. Hence proper maintenance of transmission as well as distribution network is mandatory for efficient and effective distribution of power. Though the losses associated with generation can be exactly formulated, there is no proper and precise quantification of transmission and distribution losses. Many parameters are involved and hence more data is required in addition to the sending end data. Also it is not only the technical parameters that influence transmission and distribution losses, but also the non-technical parameters. Power theft is one such parameter in developing countries. In India, the power theft is highly significant and it is approximately 420MW accounting to heavy revenue loss to power utilities . A design is proposed for detecting the power theft with an automatic Circuit breaker and disseminating the information to concerned authorities using wireless radio link .

POWER THEFT PREVENTION IN DISTRIBUTION SYSTEM USING SMART DEVICES
. INTRODUCTION
There is a huge demand for electricity and there is always a mismatch between supply and demand. Satisfactory operation of power systems requires overall coordination of all the power system components. Attention and focus are given for generating power using both renewable and conventional sources of energy. But the transmission of power also plays a vital role in conveying power with minimal loss to the consumers. Hence proper maintenance of transmission as well as distribution network is mandatory for efficient and effective distribution of power. Though the losses associated with generation can be exactly formulated, there is no proper and precise quantification of transmission and distribution losses. Many parameters are involved and hence more data is required in addition to the sending end data. Also it is not only the technical parameters that influence transmission and distribution losses, but also the non-technical parameters. Power theft is one such parameter in developing countries. In India, the power theft is highly significant and it is approximately 420MW accounting to heavy revenue loss to power utilities. A design is proposed for detecting the power theft with an automatic Circuit breaker and disseminating the information to concerned authorities using wireless radio link .

The limitation in controlling devices and the issues related to power theft had been discussed taking into account of the non-technical losses . A predictive model for power theft detection in distribution network with smart meters had been proposed. Also, a statistical estimation procedure is used to minimize the error and noise in the measuring process . The influence of low maintenance and transformer failure on electricity theft had been analyzed . The design of smart distribution unit for ring main distribution system with intelligent electrical device module had been proposed. In addition, a two relay protection algorithm for detecting and locating the fault had been analyzed . Various methods on the impact of power theft and implementation of different devices had been described and discussed in literature

ELECTRICITY THEFT METHODS
There are various types of electricity power theft in meters, cables, transformers and overhead lines. Some of them are listed below:
• Tampering with meters and seals
• By-passing the meters
• Damaging or removing meters wires
• Illegal tapping to bare wires or underground cables.
• In Cables Transformers
• Illegal terminal taps of overhead lines on the low voltage side of the transformer.
• Billing irregularities made by meter readers.
• Other unpaid bills by individual customers, government and private organizations

IMPACTS OF ELECTRICITY THEFT Electricity theft causes dangerous and severe impacts. Generally electricity theft affects the utility company revenue and then its customers. The major impact of electricity theft is leads can’t able to meet the load demand by installed capacity. It’s also leads to generation unit overloading. It creates lack of funds to operate and to manage the facilities and leads to lack of exposure to new technologies.
PROPOSED MODERN LAYOUT
The new layout of distribution system is based on combining wireless network with existing electrical grid. The architecture consists of five sections namely, Automatic controlling unit, Zigbee module, Current transformer, circuit breaker, Frequency disturbance generator.
ANALYSIS OF LOSSES
In electrical power systems losses are acquired in two ways: • Technical losses and • Non-technical losses (Cost-effective losses) Technical Losses: – Technical losses will always arise as the behavior of electricity transport means that, no power system can be flawless in its delivery of energy to the end customer. The direct power loss. Ploss (t) in a transmission line can be expressed as:
P (t) P (t) P (t) loss source load = − 1 Where Psource (t) is the direct power that the source injects into the transmission line and Pload (t) is the direct power consumed by the Load at the other end of the transmission lines. Non-Technical Losses (Cost-effective Losses):- Losses incurred by equipment failure are quite rare. These include losses from equipment struck by lightning, equipment damaged by time and neglect. Best power companies do not allow equipment to failure in such a way and fundamentally all companies keep some form of maintenance policies.
Other possible causes of cost-effective losses are:
I] Errors occurs in accounting and record keeping that misrepresent technical information.
II] Mistakes in technical loss calculations.
III] Electricity bill non-payment by consumer.
IMPLEMENTAT ION OF ZIGBEE BASED POWER THEFT PREVENTION METHOD
Using zigbee, the illegal usage of power can be solved electronically without any human control and wirelessly. The simple working principle of this method is the comparison of the current passed through the distribution transformer current sensor value and the total algebraic sum of current sensor values the consumers connected to that transformer. A current transformer and circuit breaker with ZIGBEE module is placed at each of the consumer terminal. It measures the total current consumed by the consumers and it transfers to the substation. It is compared with the current sensor reading of the current sensor placed at the distribution transformer. If both the values are equivalent, then there is no theft (Transmission and distribution losses are neglected). However if the value of the transformer current sensor reading is greater than the consumer’s current sensor reading, then the theft is acquired. By the help of this mismatching error readings, we can detect the power theft. After conformation we generate frequency disturbances using cyclo-converter and given to illegal customer to damage their loads.

Current sensor:
A current sensor is a device that produces a signal proportional to the electric current (AC or DC) sensed in a wire. The generated signal can be either analog or digital and the signal parameter can be either current or voltage. The measured current can be displayed in ammeter and is applied for controlling and protection purposes. Sometimes this data is used in data acquisition system for further energy management.
Cyclo-Converter:
A cyclo-converter (CCV) or a cyclo-inverter converts a constant voltage, constant frequency AC waveform to another AC waveform of a lower frequency by producing the output waveform from segments of the AC supply without an intermediate DC link. There are two main types of CCVs, circulating current type or blocking mode type, most commercial high power products being of the blocking mod type.
.Zigbee:
Zigbee is a universal wireless standard that enables smart gadgets to work to work together. It is widely used in commercial and industrial application because of its benefits and intended to exchange data through hostile RF environment. Incorporating the facilities like direct sequence spread spectrum, low duty cycle, low latency, encryption of data and supporting multiple network topologies are simpler as well as easier with zigbee. The zigbee module of IEEE 802.15.4 standard is used in this paper. It is best suited for low cost and low power applications. Recent trends like smart energy, smart grid, automatic meter reading, lighting control and control of high voltage AC transmission lines use Zigbee for controlling purpose. It enables to get high performance with ultra-low power with the help of smart RF transceiver.

CONCLUSION
This paper explains various circumstances, obstacles in the scheme, progress, arrangement, development, and maintenance of electricity theft controlling devices. In addition, various issues that provokes people to steal electricity are discussed. The various reasons and causes of electricity power theft is analyzed. A wide study on the existing methods of power theft detection and prevention is made. This paper focuses on power theft by hooking in low voltage lines. A scheme of injecting frequency disturbance in distribution line for avoiding illegal power consumption. A wireless zigbee module of IEEE 802.15.4 standard is employed for this purpose

(PDF) Power theft prevention in distribution system using smart devices. Available from: https://www.researchgate.net/publication/283308026_POWER_THEFT_PREVENTION_IN_DISTRIBUTION_SYSTEM_USING_SMART_DEVICES [accessed Sep 13 2018].

Dr.S.Thangalakshmi
G.Sangeetha bharath
S.Muthu

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