RESEARCH PROPOSALGRID-TIED POWER GENERATING BASE TRANSCEIVER STATIONS BY Giles Doro Reg No R123429P The inverter monitors the alternating current mains supply waveforms and generates electricity that is phase matched. . and environmental challenges. The DC electrical system is attached to the mains via this mechanism. service delivery and subsequently user experience. which are by far the most common energy source as backup power and for remote base stations today. This is a semi-autonomous electrical generation system which links to the mains to feed excess capacity back to the local mains electrical grid. Diesel generators.PROBLEM STATEMENT Currently in the Zimbabwean Telecommunications sector. logistical. electricity can be drawn from the mains grid in the situation of a generating shortfall or discharge in batteries The Power generating BTS would not require a diesel generator. The unreliability of the current power structure inspired the author to look for more robust power solution that not only improves site availability but also reduces emissions and operational expenses. Most Base Stations have back up power to grid electricity using Generator sets. Site unavailability affects telecoms network performance. site availability is mainly affected by power challenges due to load shedding and generator faults. present a number of economic. GENERIC RESEARCH ON THE PROBLEM The student has come up with a notion to implement a grid-tied solar power system that reduces site downtime. Because the local system is phase matched. The solar panels would capture Direct Current electricity which is then passed to a grid tied inverter. Zimbabwe is geographically located in the Savannah region. This results in frequent disruption of service and subsequent revenue loss.grid areas.Figure 1: Power Generating BTS Architecture In the event of a power fault. which are conducive for solar power generation. moderated by altitude. When the generator produces more electrical than the power required to charge the DC batteries. In this way we can ensure that the BTS. the total amount of power generating using this method would be . which has one of the highest average sun light hours per day and intensity levels in the world. equipment damage. mountains in east. then the excess power is wasted. Taking into consideration the vast number of BTS sites spatially located within the national grid coverage across the country. There was therefore a need to come up with a more power efficient design that did not have high maintenance costs such as servicing and refuelling. This results in unnecessary excess cost and wastage of energy. and other problems. the robust power generating base station system becomes gridindependent by using a battery bank to provide stored power. rainy season (November to March). This “hybrid” approach will both fix long-term energy costs and provide security. MOTIVATION AND BACKGROUND OF STUDY Power outages are currently the major cause unavailability of BTS and NodeB units. The climate in Zimbabwe is typically tropical. generator mechanical faults contribute significantly to this downtime. communications equipment or other “critical loads” are not unexpectedly shut down. The terrain: mostly high plateau with higher central plateau (high veld). thus avoiding data loss. In the remote off. Generators work by converting mechanical energy to electrical energy. Solar photovoltaic cells convert sunlight to direct current electricity. thereby minimizing mechanical failures No wasted energy.g. excess electricity is sold back to the grid in cases where the solar system has generated more energy than that the capacity of the batteries No power loss due to inductance Bill Reduction Green Energy METHODOLOGY This project is going to be simulated by using a grid tied inverter inter-connecting to a miniature solar panel system and the national power grid. telecommunication service providers can use excess solar electric generation to offset utility-purchased electricity on a monthly or annul basis by means of a concept known as net metering. implying that they are normally in an open and elevated area. by contributing excess power back to the grid and in the process generating revenue. BTS and NodeB units are already usually located where there is a line of sight vision to other sites. which is also the ideal environment for the solar systems No running costs e. This concept would be able to help alleviate the current national power crisis. fuel resulting in power savings No moving parts. Direct Current electricity is then passed to an inverter which is grid tied. The inverter monitors the alternating current mains .Using a simplified approach for interconnecting and metering on-site renewable generating facilities. Advantages of the Power Generating Base Station Excess electricity can be sold to mains. A Graphical User Interface will compute the net power transfer between the solar system and the grid in real time using the generic kWh calibration.significant not only to serve the purpose of maintaining the site up but also to reduce load shedding . Electrical shortfall can be bought from mains. As a solar PV system starts generating electricity. The DC electrical system is attached to the mains via this mechanism as shown in the figure below. electricity can be drawn from the mains in the situation of a generating shortfall or discharge in batteries. The main objective is to be able to fully utilize grid and backup power system in order to get the best of both in a cheap and effective manner that not only helps to alleviate the national power crisis but also contributes to a cleaner environment and less equipment downtime.supply waveforms and generates electricity that is phase matched. slowing down the power being supplied by the grid. based on the signal from the control circuit. AIM AND OBJECTIVES OF THE RESEARCH The aim of the project is to use the sun’s energy to create a robust power system that reduces site downtime. . the inverter activates a transfer switch which opens its connection to the grid. When there is load shedding or grid power is lost for some reason. A Java based GUI metering system will then account for the overall power usage. Because the local system is phase matched. It is very common that later on in the day the solar PV system may produce more power than what is needed at the site. as well as keep energy off the power lines so utility workers don’t get shocked. it first goes to meeting the on-site electric demand at the Base Station. The inverter also converts the dc power to ac power when feeding back to the grid. This keeps the inverter from trying to power other devices in the grid. The solar panels will be implemented in a fixed tilt position as part of the BTS equipment shade roofing. at which point the “excess” electricity will automatically back feed through the bi-directional meter. cuts running costs and possibly even create revenue. Interfacing/interconnection with the grid is done through a circuit breaker on the main electric service panel. Single phase full bridge inverter 20 Watt 12 V mono-crystalline solar Panel/DC Power Supply Charge controller circuit 12 Volt Lithium Ion Battery Circuit board Laptop computer MSP430 microcontroller Resistors and capacitors KEY QUESTIONS TO BE ANSWERED . Assemble hardware components and software Testing of hardware components and software compatibility Testing of hardware components and software Hardware compatibility with software System testing and presentation LIST OF RESOURCES REQUIRED.WORK PLAN. TIME LINE March April May June July September October November ACTIVITY Layout design completion of research proposal Design AC-DC conversion circuitry and line monitoring mechanism Program the GUI and test with dummy input. Layout and wiring. Navigant Pike Report 2012 .Renewable and Alternative Energy Sources for Remote Mobile Telecommunications: Global Market Analysis and Forecasts.Circuit board wires Soldering iron Soldering gun Visual Studio software References http://www.com/news-releases/off-grid-power-for-mobile-base-stations---renewableand-alternative-energy-sources-for-remote-mobile-telecommunications-global-market-analysisand-forecasts-188185711 Off-Grid Power for Mobile Base Stations .prnewswire.