Over the past two decennaries, the nomadic telecommunications industry has grown exponentially on a planetary graduated table. In a state, the Mobile sector has become a critical index of economic development [ Kenny & A ; Keremane 2007 ] . However, the potency of nomadic telecommunications has non been to the full utilized in the development states. As an indicant, the incursion rate of nomadic phones in Africa is 22 % , which contrasts that of 94 % in Europe [ ITU 2007 ] . This is because the basic substructures available in the European states are non available in the underdeveloped states like Nigeria. However, wireless deployment in Nigeria is faced with some jobs and the key among them is the undependable power supply state of affairs in Nigeria. [ Ndukwe C. , Telecommunication Challenges for Nigeria in the twenty-first Century, 2000 ] . A intercrossed power system and site plus director for base transceiver station in nomadic telecommunication will supply a system that will supervise and command the power system in the station, so that the sites will non be powered on Diesel generator for the whole 24 hours of the twenty-four hours and besides maintain a path record of the activities of equipments on the site.
The purpose of this undertaking is to plan a control system that will supervise and command the power system of a base transceiver station in other to cut down the cost of coevals energy by cut downing the measure of Diesel used by a site per twenty-four hours to bring forth energy and besides be able to supervise the activities of the other support equipments and maintain a path record of it for probe and analysis intents.
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This would cut down the C emanation by the Diesel generator at the sites by at least 40 %
To accomplish the chief purposes of this undertaking, the below stated aims are considered.
Analysis of the present system in topographic point. This survey was done to understand how the power system of the site is being organized.
To plan a intercrossed power system that will prolong the site more on the battery that on the Diesel generated power.
To place where and what detectors are to be used for informations acquisition.
To plan a communicating channel that will non merely enter the activities of the site but will be able to direct a escalation to the field officers straight on pressing issues.
A typical Mobile Telecommunication base transceiver station in Nigeria is powered with one or two diesel generators and it operated the 24 hours of the twenty-four hours. Either in bend of 12 hours each for site with two generators or 24 hr for the sites that have one generator. For an mean 17.5kVA to 20kVA Diesel generator consumes about 2.1liters/hr and in one twelvemonth ( 8,760 hours ) is 18,099liters.
Weekly Nigeria Bonny Light Spot Price FOB ( Dollars per Barrel )
From the graph above, it will be shortly that the monetary value of crude oil is on the addition and this has lead to the addition in cost of energy coevals.
The care service for the generators is scheduled for every 250 hr running clip which translates to 10 yearss 10 hours intending about 3 times a month. The high frequence of care service times besides adds up to the running cost of running the web and in a few more months the generator will make the upper limit allowed hours for generator being used and so it has to be changed.
To be able to analysis the behavior of your assets in the site ; there is demand to hold certain information at different point in clip. This information can uncover the behavior of your generators, the temperature at which your equipments are working in, to look into if there is an inordinate use of Diesel, larceny or waste and will besides uncover points of unauthorised invasion.
To hold a record for mention during probe of any kind refering activities of the site and to make out the responsible field office in charge of the site on instances the requires pressing attending and if let on the custodies of the Network Management Center will be disciplinary alternatively of proactive.
I have for six old ages worked in this environment, where we powered the base Stationss with lone generator and I was oversing approximately 120 base Stationss for Zain Nigeria and subsequently I managed base transceiver Stationss for D’pramik Integrated Service for some other Network Provides and the same was practiced. With my new consciousness in Engineering, I have proposed to a system that will cut down on the measure of Diesel used purchase the base station and in add-on increasing the control over the activities of the base Stationss.
1.4 SCOPE OF THE STUDY
This designed system can be used in other installations in a nomadic telecommunication but I am establishing this design on the base transceiver station for the intent of the undertaking. The system will get power parametric quantities from the generators, the national grid and the battery bank and will exchange supply between them. It will mensurate and maintain path of the measure of Diesel in the armored combat vehicle, proctor interlopers and keep the temperature of the shelter to be contributing for the equipments. The system will pass on via electronic mail to the staff officer responsible for any affected site and will besides update its record.
1.5 Undertaking LAYOUT
This chapter presents the background, purposes, nonsubjective and the motive behind the idea of planing a system to accomplish the declared purposes. The chapter 2 will concentrate on the literature reappraisal of a nomadic telecommunication. It ‘s architecture and the layout of a base transceiver station and ends with the functionality of the present system. The chapter 3 will turn to the method by which I am suggesting to utilize in accomplishing my purposes ( Design ) . Chapter 4 Execution of the design. Chapter 5 Cost Analysis. Chapter 6 Conclusion. Chapter 7 Further Study.
Chapter 2 LITREATURE REVIEW
2.1 REVIEW OF THE GSM ARCHITECTURE
A GSM web is composed of several functional entities, whose maps and interfaces are specified. The GSM web can be divided into three wide parts viz. :
Switch overing System ( SS ) .
Base Station System ( BSS ) .
Mobile Station ( MS ) .
In add-on, with the nomadic telecommunication web is monitored, maintained and operated from a cardinal point known as the Network Management Centre ( NMC ) .
United self-defense force of colombia
United states secret service
Master of science
Bachelor of science
Fig 2.1 GSM ARCHITECTURE
2.1.1 Switch SYSTEM ( SS )
The Switching System ( SS ) provides all the functionality needed to manage a nomadic endorser such as enrollment, hallmark, location updating and handovers and name routing to a rolling endorser. These services are provided in concurrence with several functional entities viz. :
Mobile Switching Center ( MSC ) .
Gateway Mobile Switching Center ( GMSC )
Home Location Register ( HLR ) .
Visitor Location Register ( VLR ) .
Authentication Center ( AUC ) .
Equipment Identity Register ( EIR ) .
18.104.22.168 MOBILE SWITCHING CENTRE ( MSC )
The MSC is responsible for commanding calls in the nomadic web. It identifies the beginning and finish of a call whether it is from a fixed telephone or a nomadic station.
22.214.171.124 GATEWAY MOBILE SWITCHING CENTRE ( GMSC )
The GMSC performs the same responsibility as the MSC but this clip merely to the inter-network endorsers. It besides enables an MSC to interrogate a web ‘s HLR in order to route a call to a Mobile Station ( MS ) .
126.96.36.199 HOME LOCATION REGISTER ( HLR )
The HLR is a centralised web database that shops and manages all nomadic subscriptions informations belonging to a particular operator. It acts as a lasting shop for a individual ‘s subscription informations until that subscription is canceled.
188.8.131.52 VISITIORS LOCATION REGISTER ( VLR )
The VLR is a database which contains information about endorsers presently being in the service country of the MSC. It besides carries out location enrollments and position update.
184.108.40.206 AUTHENTICATION CENTRE ( AUC )
The AUC ‘s chief map is to authenticate the endorsers trying to utilize a web and by this manner protects the web operators against fraud.
220.127.116.11 EQUIPMENT IDENTITY REGISTER ( EIR )
The EIR is responsible for IMEI ( International Mobile Equipment Identity ) checking. This is an act of look intoing the Mobile Station ( MS ) .
2.1.2 BASE STATION SYSTEM
The Base station system map is to pull off the Radio web and it is controlled by the MSC. Typically, one MSC controls several BSSs and a BSS itself may cover a well big geographical country dwelling of many BTS or Cell. A BSS consists of:
Base Station Controller ( BSC ) .
Base Transceiver Station ( BTS )
FIG 2.2 Base transceiver station web.
18.104.22.168 BASE STATION CONTROLLER ( BSC )
The BSC manages all the radio-related maps of a GSM web. It is a high capacity switch that provides maps such as MS handover, wireless channel assignment and the aggregation of cell constellation informations. A figure of BSCs may be controlled by each MSC.
22.214.171.124 BASE TRANSCEIVER STATION ( BTS )
The BTS controls the wireless interface to the MS. The BTS comprises the wireless equipment such as transceivers and aerials which are needed to function each cell in the web. A group of BTSs are controlled by a BSC.
The MS is a combination of Mobile equipment ( ME ) and the Subscriber Identity Module ( SIM ) . The SIM contains the endorser ‘s information and it is plugged into a ME ( Mobile manus set ) .
SITE LAYOUT OF A BASE TRANSCEIVER STATION
Figure 2.0 Typical base transceiver station site floor program.
The BTS structural layout is categorized based on the lodging of the Radio equipment. There are three basic types viz.
Indoor BTS Site.
Outdoor BTS Site.
Roof Top BTS Site.
The Indoor BTS Site is a structural layout designed with a shelter that houses the wireless equipments. It is composed of one or two diesel generator sets, Automatic Transfer Switch ( ATS ) , one Diesel armored combat vehicle of capacity of non less than 3000 litres, oil cooled transformer, a tower whose height depends on the wireless nexus design and a security hut for the guard.
The Outdoor BTS Site is a layout design that does non incorporate any shelter but out-of-door cabins that house the wireless equipments. It besides contains one or two Diesel generator, Automatic Transfer Switch ( ATS ) , an oil cooled transformer, a Diesel armored combat vehicle, a tower and a security hut.
The Roof Top BTS site layout is situated on top of a edifice roof. The wireless equipment is either housed in a shelter or out-of-door cabin or a room in the edifice. It besides contains one or two generators at the land floor of the edifice, Automatic Transfer Switch ( ATS ) , a Diesel armored combat vehicle, an oil cooled transformer and a mini pole saddle horses for the wireless aerial.
2.2 PRESENT POWER SYSTEM STRUCTURE
2.2.1 NATIONAL GRID SUPPLY
Presently electric power supply in Nigeria is the duty of the federal authorities owned National Electric Power Authority ( NEPA ) , which has been late restructured into a keeping company named Power Holding Company of Nigeria, ( PHCN ) in readying for deregulating. NEPA was established in April 1972, with the merger of the former Electricity Corporation of Nigeria ( ECN ) and Niger Dams Authority ( NDA ) . NEPA supplies electricity power to an estimated four million clients in Nigeria and the Niger Republic, from a combination of hydroelectric dikes, coal and gas powered runing beginning.
A A Like most state-owned endeavors, NEPA has suffered from terrible under support and under-capitalization, inappropriate capital construction, inordinate executive intervention, and sub-optimality and decision-making.A
A A The effect of this tendency is a structural imbalance between electricity power demand ( estimated at 10000MW in 2005, forecasted to lift to 20,000MW in 2010 ) , and supply. Although the installed capacity is about 6000MW, the maximal burden, of all time recorded, was 3083MW. With a 40 % coevals and distribution losingss, the attendant power outages cost the state an estimated $ 1 billion per twelvemonth ( 2.5 % of GDP ) [ Ayodele 2003 ] . The Nigerian national electric grid comprises of three hydro and six thermic bring forthing Stationss with a sum installed capacity of 5906MW.
A Table of Power Generation and Capacity in Nigeria ( 2007 )
Entire Installed Capacity
Steam and Gas
Domestic Supply Voltage – 220V
Frequency – 50Hz
The tabular array above shows an installed capacity of 5951.6 MW but it is sad to observe that in 2007 available capacity from generators is merely approximately 2536.6MW, less than 50 % of the install capacity. The transmittal grids are to a great extent overloaded, because transmittal capableness was non expanded with increasing MW added to the transmittal grid. Harmonizing to a survey done by [ O.A Komolafe et Al 2003 ] the transmittal grid is limited to a load supply of 4000MW. This bound includes the consequence of Var Injections and Voltage control equipments. If all the available capacity of 5951.6MW is injected into the transmittal, entire system prostration will happen. Transmission losingss are estimated to be 20-30 % yearly.
The deficiency of equal electric power has caused the prostration of many industries that rely to a great extent on equal power supply. Small concerns and to a great extent machined makers are badly affected excessively by the abysmal public presentation of PHCN.
A Diesel generator is a combination of a diesel engine with an electrical generator ( alternator ) to bring forth electricity energy. In this state of affairs, the chemical energy stored in the Diesel is converted to mechanical energy through burning in the engine and the engine in bend moves the alternator to bring forth electrical energy. The operational restraints for a Diesel generator are ;
the minimal operating burden, the minimal tally clip for the Diesel engines, and the whirling modesty ordinances for the system and the Diesel engines are ne’er allowed to run below a certain per centum ( normally 40 % ) of its rated power, to avoid critical care jobs. Then there are the starting and tick overing cost facets, lending to the entire system operational economic sciences [ Mahon 1992 ] .
The alternator comes in individual and three stage and the capacities ranges from 7.5kw to every bit big as 1MW.The Nigerian electricity criterion is 220V in 50Hz.
CARBON EMISSION FOOTPRINT.
Rectifiers are electronics circuits that are used to change over AC into DC. Most of the electronic devices require DC electromotive forces and current for their operation. The attendant DC electromotive forces are besides used in bear downing the battery bank in the system. [ Nair, 2009 ] [ Deepa, 2009 ] .
Rectifiers are by and large of two types viz. :
The Half-Wave Rectifier – rectify merely the positive or the negative half-cycles of the applied AC. It achieves this action with the PN rectifying tube which conducts to a great extent when forward biased and has a negligible current flow in the rearward way. [ Nair, 2009 ] [ Deepa, 2009 ] .
The Full-Wave is rectified in both half-cycle utilizing rectifying tubes D1 and D2. Full moving ridge rectifiers are of two types:
Full-wave center-tapped rectifiers.
Full-wave span rectifiers.
Full-wave center-tapped rectifier uses a center-tapped transformer for its operation. The diagram below shows that during the positive half-cycle, D1 conducts and D2 remains OFF, Current ID1 flows through RL in the way shown. During the negative the negative half-cycle, D2 conducts and D1 remains OFF and we find that the rectifying tube current ID2 flows in the same way as ID1 through RL. Thus, circuit rectifies both half-cycles and this is called Full-Wave rectifier. [ Nair 2009 ] [ Deepa 2009 ] .
Full-wave Bridge Rectifier uses a four rectifying tube in span to accomplish the AC electromotive force rectification. [ Nair 2009 ] [ Deepa 2009 ] .
2.2.4 BATTERY SYSTEMS
There are two different types of batteries viz. , Primary and Secondary Batteries. The Primary batteries are non-rechargeable whereas the secondary batteries are rechargeable. Different battery systems are available for the both primary and secondary. Each battery system is characterized by its chemical science. Examples of Primary batteries are zinc-carbon ( Lenclanche ‘ , besides known as zinc-manganese dioxide ( ZnMnO2 ) ) , zinc-alkaline-MnO2 ( besides known as alkalic batteries ) and some secondary batteries are sealed lead-acid ( SLA ) , NiCd, NiMH etc. [ Henk J, et Al, 2002 ] .
The Basic electrochemical unit used to bring forth electrical energy from stored chemical energy or to hive away electrical energy in signifier of chemical energy is known as a Cell. A cell consists of two electrodes in a container filled with electrolyte and a combination of two or more cells is known as a battery. There are two electrodes in a cell. The positive electrode is Anode and the negative electrode is Cathode. The electrodes are separated with an ion-permeable, electrically non-conductive stuff or spacer that prevents short-circuiting which is known as a Separator [ Henk J, et Al, 2002 ] .
Cycle Life – The figure of rhythms that a cell or battery can be charged and discharged under specific status, before the available capacity in ( Ah ) fails to run into specific public presentation standard. This will normally be 80 % of the rated capacity. [ Henk J, et Al, 2002 ] .
Cut-off electromotive force – The cell or battery electromotive force at which the discharge is terminated. This is besides referred to as End-of-Discharge electromotive force.
Self-Discharge – The recoverable loss of capacity of a cell or battery. This is normally expressed in a per centum of the rated capacity lost per month at a certain temperature, because self-discharge rate of batteries are strongly temperature dependant.
TYPES OF BATTERY
NiCd Batteries – The NiCd batteries are comparatively inexpensive and robust. It can provide big current and can be charged in a comparatively short period of clip, every bit low as 10 proceedingss. It has an mean cell electromotive force 1.2V. The features of high power delievery and rechargeable clip make NiCd batteries to be really popular in power tools and cordless phones. The NiCd batteries have some drawbacks. First, their energy, specific energy and comparative energy are comparatively low. Second, it suffers from memory consequence [ Prochaska 1994 ] . This consequence can be defined as a diminution in effectual capacity with repeated partial charge/discharge rhythm. As partial cycling continues, the battery will finally merely be able to provide the capacity retrieved from the partial cycling. [ Henk J, et Al, 2002 ] .
NiMH batteries – NiMH batteries have an mean operating electromotive force of 1.2V for the cell and has a higher energy denseness that the NiCd batteries. The anode is a metalhydride ( MH ) metal and is capable of hive awaying H in a solid province. The self discharge of the battery is more than that of the NiCd because of its ability MH electrode to retain the stored H in a solid province ; the more H it retains the more its selfdischarge rate will be. Finally is less robust to the NiCd batteries due to the fact that it surfers soaking that the NiCd. This means that the bear downing procedure of the NiMH batteries will be more accurate to forestall over charging.
Li-ion Batteries – Li-ion Batteries has a high operational cell electromotive force of 3.6V and
2.2.5 AUTOMATIC TRANSFER SWITCH ( ATS )
An automatic transportation switch is a public-service corporation device that transportations from one beginning of power supply to another automatically in instance of power failure. It is an of import facet of backup power supply systems and power dependability.
A basic generator has an internal engine starting and other operational controls, the ATS does the existent control of timing of the engines get downing, warming, burden transportation ( either timed or mistake triggered ) and closing down. It is a separate unit from the generators or the Utility grid systems.
The basic map of an ATS is where there is a sudden outage of power and the operation disrupted could take to a catastrophe if the outage is prolonged. Cases like the fabrication, procedure works, infirmary ; the ATS will automatically get down the stand-by generator and reassign power supply to reconstruct power without any human intercession. The same happens when the chief beginning of power is restored ; it will give it clip to stabilise so reassign the burden back to the chief power supply and close the generator down [ Curtis 2007 ] .
TRANSFER SWITCH TECHNOLOGY
The automatic transportation switch functionality is based on feeling a important bead in electromotive force like 80 % of the nominal electromotive force. When the electromotive force falls below the 80 % of the nominal electromotive force, the hold timer starts numbering down a preset clip to farther asses the incoming electromotive force and if the electromotive force does non normalise. It will signal the stand-by generator or stand-by power beginning and one time the stand-by is ready to accept burden ; the ATS will reassign the burden to the stand-by.
If the brinies electromotive force falls back to normal for a period of clip, the ATS will first of all transfer the burden back to the brinies and delay for a piece ( preset hold clip ) and sends signal to the generator to close down.
TYPES OF TRANSFER SWITCHES
MANUAL TRANSFER SWITCHES
AUTOMATIC TRANSFER SWITCHES
MANUAL TRANSFER SWITCHS
2.2.6 EQUIPMENT PROTECTION
POSITIVE GROUND SYSTEM
SWITCHING CIRCUTRY SYSTEM AND POWER FLOW
Automatic Transfer Switch
Utility Grid Supply
The above diagram is a Standard Zain Nigeria power flow diagram for a Base transceiver station. It comprises of two generators, a public-service corporation grid supply, an Automatic transportation switch, a battery bank and a rectifier. A mains power supply from the ATS unit is dropped in a Distribution box inside the shelter, from where it is distributed to the rectifier, air-condition units, the guard hut, the illuming points in the shelter and the tower. The rectifier converts the power from 220V AC to 48V DC and feeds it to a DC coach saloon. The battery bank is besides connected to the coach saloon and in bend the coach saloon to a DC Distribution box.
In the ATS the generators are programmed to run for 12 hr each and after which the 2nd generator takes over a bend of 12 hr and the switch method is the unfastened passage switch. At the point of generator transfer the ATS timer relay will direct a signal to the running generator to halt and it waits a preset clip hold for the generator to halt. Again, the timer relay sends a signal to the 2nd generator to get down, run and exchange over to lade. The wireless equipments in the shelter will non be affected by the small clip of transportation because they are supported by the battery bank current. If at any clip the Utility grid supply comes ON, the ATS senses it and automatically transportations the burden to the public-service corporation grid and sends signal to the running generator to halt and if the public-service corporation grid subsequently goes away. The timer relay in the ATS will direct a signal to the coevals that its clip is running on its counter to get down and after a preset clip, the burden is transfer to it and the procedure goes on and on.
Chapter 3 DESIGN THEORY
3.1 GENERATOR MANAGEMENT
3.1.1 VOLTAGE Monitoring
3.1.2 CURRENT Monitoring
3.1.6 GENERATOR ALARMS
3.2 NATIONAL GRID SUPPLY
3.2.1 VOLTAGE Monitoring
3.2.2 CURRENT Monitoring
3.3 BATTERY MANAGEMENT
3.3.2 BATTERY Voltage
3.3.3 BATTERY CURRENT
– Deep CYCLE BATTERY