1.1 Background to the Study
Electricity is very crucial to the socio-economic and technological development of every country. One of the indices used to measure the development of an economy is uninterrupted power supply. It is widely accepted that there is a strong correlation between the availability of electricity and socio-economic development. The supply of electricity in Nigeria incurs substantial capital. The enormity of these costs is growing astronomically across the globe. To decipher the unlawful users of electricity in a bid to enhance the economy of utility company, efficiency and protection of the grid, a novel procedure for scrutinizing electricity usage patterns of customers and recognizing illegal consumers is proposed and implemented. Nigeria electric power network operator, electricity Distribution Companies of Nigeria (DISCOs) has for a long period of time been combating the problem of revenue collation. This is majorly attributed to the fact that electricity bills are sent to consumers after consumption. Consumers are usually unwilling to pay electricity bills as a result of epileptic nature of the electricity supplied which is not usually mirrored in the bills which are basically estimates of power usage and not usually commensurate to the true amount of electricity consumed by the respective consumer.
The low reliability of electric power supply has little bearing on the network operator because whether power is provided or not, in the post-paid method, the monthly electricity bills are still sent to consumers. Hence, the user bears the cost of generating power for their personal usage as well as that of the electricity that was never provided by DISCOs. Due to the enormity of the debt accrued by customers, the network operator initiated a cash collection policy named Revenue Cycle Management (RCM) which involves collecting monies owed through private establishments. This failed to give the anticipated results; hence DISCOs came up with the digital pre-paid meter in 2006 whose operation is somewhat synonymous with the loading of an airtime voucher in the Global System for Mobile communication (GSM) handset. If power is available and the pre-paid meter is loaded with units, the loaded unit diminishes only when the load is connected and stops when power is interrupted. In the last decade, smart cards evolved from basic memory cards to complex systems on chips with a processing power that can be expanded. This became an avenue for the invention of many applications used in the world today. The smart card, an intelligent token, is a credit card sized plastic card embedded within an integrated circuit chip. A smart card usually consists of a Read Only Memory (ROM) or flash memory, Electrical Erasable Programmable Read Only Memory (EEPROM) and a Central Processing Unit (CPU). The smart card operating system controls access to data on the card. The card operating system does not only make the smart card secure for access control, but also has the capability to store a private key for a public key infrastructure system.
Recently, the industry has come up with 32-bit smart card processors having more than 400Kbytes of EEPROM, and a memory management and protection unit serving as a firewall for the hardware. This hardware firewall enables secure separation of adjacent applications, as well as being the basis for secure downloading of applications. The self-containment of smart card makes it somewhat attack proof as it does not need to be relied upon potentially attack susceptible external resources. Due to this feature, smart cards are often used in diverse applications which require strong security and authentication. In addition to information security, smart cards achieve greater physical security of services and equipment, because a smart card limits access to only authorized users.
Furthermore, the smart card can be used as a credit/debit bank card which makes it relevant for e-commerce applications. The multi-application smart card, along with the advent of open platform smart card operating systems, brings the only viable option for handling multiple electronic transactions these days. It is a cost effective secure way to manage transactions electronically Manufacturers, issuers and users have come to appreciate the value of one card that manages multi-applications. A multi-application card will be able to amongst other things do an automatic update of new services as well as existing applications, change and store user profiles for each application and be usable on a range of devices. One of the most valuable applications is in using the smart card to buy energy. Recently, the portal technology has been playing an increasing role in computing. Service providers are rolling out portals to allow users to create customized web sites that display exactly the information on the Card and transformer. Corporations are rolling out portals to provide employees and business partner’s customizable access to corporate information. For web enabled energy services, and with the introduction of home networking technology, power companies and service providers can offer value-added services to the homes, like energy management, to generate additional revenue as well as to increase convenience and loyalty. In this research work, we propose a novel and simple prototype of a web enabled smart card based solution for controlling the consumption of electricity in a home environment. The proposed system can calculate the total voltage consumption and the structure health condition of the transformer as well as the total voltage distributed by the transformer. For a while now, energy conservation has been a topical issue. In practical terms, people use much more power than what they actually need and that is responsible for the consequent huge loss of energy.
Moreover, the continuous increase in the universal energy prices has led to a colossal economical loss. Thus, we are proposing a prepaid electricity smart card based system that will enable people to buy specific quantum of energy for use only when needed. People can subscribe for this service and recharge their accounts through the Mobile Phone. The power meter used in this study interrupts the controller at a rate of 0.75Wph based on the particular tariff used and the amount of power consumption needed, the correct amount of money to be loaded into the card can be easily calculated and programmed into the chip. The unique feature about this system is that the electric utility in the home environment can be accessed remotely from the supplier server. The study provides people with the opportunity of buying electricity in advance, using the prepaid electricity cards. Thus, people can use only the amount of power they really require.
The proposed power management system will benefit the end customer as well as the electric utility in that the customer can recharge his account wirelessly from his home using Mobile Communication Module and the status of meter is indicated through a Short Message Services (SMS). The device will show the remaining balance so that the user knows how much he has consumed and can plan ahead and know when he needs to recharge the account and moreover, this strategy provides the utility companies the avenue to collect the expenses from customers in advance. Thus, they will no longer have to deal with late payments or non-payment of bills by the customers. This also helps to reduce electricity theft through bypass.
1.1.1 Motivation
Losses that occur during generation can be measured, but Transmission and Distribution (T&D) losses cannot be quantified completely from the end where information is sent. According to Depuru (2012), distribution losses in several countries have been reported to be over 30%. Substantial quantity of losses proves that Non-Technical Losses (NTL) are involved in power distribution. Total losses during T&D can be evaluated from the information like total load and the total energy billed, using established standards and formulae. In general, NTL are as a result of factors external to the power system. Electricity theft constitutes a major chunk of the NTL.
Electricity theft can be defined as, using electricity from the utility without a contract or valid obligation to alter its measurement. The world over, T&D losses are more than the total installed generation capacity of countries such as Germany, the UK, or France. It is estimated that around the world, utilities lose more than $25 billion every year to illegal consumption of electricity. It has also been discovered that the illegal consumption of power by the local business sector is on the increase. The quality of the power generated, transmitted, and distributed has an impact on the power system components and customer appliances. Due to the illegal consumption of electricity, estimating the overall load in real time becomes very difficult (Depuru, Wang, &Devabhaktuni, 2012).
Figure 1.1: Statistical graph of analyzing electricity theft of Nigeria, Mexico, Pakistan, Dominican Republic, Colombia, Brazil (Source: Soma and Depuru, 2012)
1.1.2 Summary of Motivation
1.1.3 Measures and Methods of Stealing Electricity
In general, electricity consumers may be categorized into genuine customers, partial illegal consumers, and illegal consumers. There are several methods used in pilfering electricity as will be discussed. The most common and simplest way of pilfering electricity is tapping energy directly from an overhead distribution feeder as shown in the Figure 1.2. The next method of electricity theft is the manipulation of energy meters that are used for recording and billing industrial, commercial and household energy consumption, as explained in Figure 1.3.
Figure 1.2: Tapping electricity directly from a distribution feeder – bypassing the meter
(Source: Soma and Depuru, 2012)
Figure 1.3: Technique used by illegal consumers to regulate the supply voltage and manipulate the energy meter reading (Source: Soma and Depuru, 2012)
There are many methods used to tamper with such meters, some of these may include:
A popular way of lowering the energy meter reading without directly tampering with the meter is shown in Figure 1.3. Here, supply voltage is regulated to manipulate the meter reading. Illegal consumers accomplish this by using one of the three phases; disconnect neutral from the distribution feeder, and using a different neutral for the return path.
Therefore, the energy meter’s working is premised on the assumption that the voltage between the connected phase and the new neutral is zero, implying that the total energy consumed is zero. Another way of stealing electricity is by isolating neutral and disturbing the electronic reference point by physically damaging the meter. The voltage to be read by energy meter can then be manipulated by controlling the neutral. Generally, illegal consumption of electricity will be predominant only within those hours of the day when the customer’s demand is high. This kind of theft (partial illegal consumption) is very difficult to measure, as the energy consumption pattern is uneven over a period of time. In addition, corrupt employees are usually responsible for billing irregularities; they record an amount of consumption that is lower than the original consumption. On the other hand, improper calibration and illegal recalibration of energy meters can also account for NTL. However, in most of the meter tampered locations, damaged meter terminals and/or illegal practices may not be visible during inspection.
1.1.4 Factors that Influence Illegal Consumers
Factors that influence consumers to steal electricity depend upon a variety of environmental factors that fall into multiple categories. Among these categories, the socio-economic factors appear to be the most predominant reason why people steal electricity. More concisely, some of the important factors are:
1.2 Statement of the Problem
The conventional electromechanical meters are being replaced by new electronic meters to improve accuracy in meter reading. Still, the Nigeria power sector faces a serious problem of low revenue collection for the actual electric energy supplied due to the fact that the utility officer carries out inaccurate calculations of voltage, current and power by the energy meter, inability of query request about the working condition of the energy meter from distant locations, the ability of the consumers to form long queues in order to buy credit for their Energy Meters, but for those that make use of the prepaid meters have to wait for several days for them to be re- connected whenever there is disconnection because some of the prepaid payment points for the purchase of token are very far from the consumers.
The major problem is the issue of bypass by the consumer, where high voltages consumptions are connected away from the meter and only low voltage consumption are connected.
1.3 The Objective of the Study
The main objective of this study is to design an Automated Remote Power Management System (ARPMS). The specific objectives are to:
1.4 Significance of the Study
The design and construction of the prepaid energy meter would help to accurately calculate the amount of consumed energy by a certain building, and indicate exact location and distribution line on which unauthorized tapping occurs. The remaining energy available from a pre-purchase of electricity is done by means of recharge through SMS service which provides the utility company with regular status of the meter on a predefined interval, and displays a real time on the user’s account update, which contributes to the retrieval of the balance of the meter, as well as keeping log of the consumed energy and remaining electricity of each user by the means of SMS, to achieve accuracy of meter reading, reduce billing error and operation cost as well as expose energy theft by bypassing voltages.
With this new system, customers are confident that they are not being exploited, power pilfering is eliminated, rogue customers are shut off, prevention of bypass and the huge revenue loss which was inherent in the traditional metering system is completely avoided.
1.5 Scope of the Study
A quad band GSM modem with a registered SIM (subscriber identification module) card with unique numbers was used in this work. The communication process employed here is achieved by installing sets of Attention (AT) command strings in the GSM modems through HyperTerminal software which comes with Microsoft operating system. With the aid of the installed AT command strings, instructions and data are sent and received by the GSM modems respectively. Data received from the consumer unit are used to update the customer’s database at the office of the power providing company.
The Electrically Erasable Programmable Read Only Memory (EEPROM) of the microcontroller is updated each time a customer pays his/her bills via SMS recharge by simply sending a secret pin from his mobile number to the developed system. Other information such as total energy consumed, total amount paid on consumption, the amount of bill paid and the amount left to be used, success of recharge, power disconnect/reconnect by the supply company, and critically low unit is communicated through the customer’s mobile phone to the customer via SMS.
1.6 Organization of the Study
The study provided background information on the subject matter by highlighting the specific objectives of the study. The central idea of the literature review in chapter two is to critically examine the Historical Development of intelligent prepaid energy meter, the required measure needed by consumers in stealing electricity, factors that influence illegal consumption, and the gap between the existing authors and the proposed intelligent prepaid energy meter.
The methodology used is the principle of embedded system with serial communication. The EEPROM of the microcontroller is updated each time a customer pays his/her bills via SMS recharge by simply sending a secret pin from his mobile number to the developed system. The user’s interface consists of Liquid Crystal Display (LCD) which displays energy consumed, the amount of bill paid and the amount left to be used. Information such as unit recharged, success of recharge, power disconnect/reconnect by the supply company, and when the unit left is critically low to avoid loss of power supply is communicated through the customer’s mobile phone to the customer via SMS.
The result and discussion describes the implementations of the system blocks diagram described in chapter 3, starting with block and system simulation, followed by block and system testing. It also discusses the results obtained from those tests and implementations.
The conclusion, recommendation & future work described tangible benefits of the system proposed in this study in terms of reducing the cost of (meter reading, detecting meter tampering and misuse of electricity). As the system is automated, the retrieved data can serve other purposes like online billing system, demand analysis, amongst others. For future work, more research can be done to develop meters that calculate the total voltage on a transformer and the cost on that voltage before it is distributed so that it can be used for comparative analysis. Furthermore, similar technologies can be designed for water meters, gas meters and other types of meters.