power generating bts

8/9/2019 Power Generating BTS

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RESEARCH PROPOSAL

GRID-TIED POWER GENERATING BASE

TRANSCEIVER STATIONS

BY

Giles Doro

Reg N o R12342 P


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PROBLE! STATE!ENT

Currently in the Zimbabwean Telecommunications sector, site availability is mainly affected by power challenges due to load shedding and generator faults. Site unavailability affects telecomsnetwork performance, service delivery and subsequently user experience.

ost !ase Stations have back up power to grid electricity using "enerator sets. #ieselgenerators, which are by far the most common energy source as backup power and for remote

base stations today, present a number of economic, logistical, and environmental challenges.

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 operationalexpenses.

GENERIC RESEARCH ON THE PROBLE!

The student has come up with a notion to implement a grid$tied solar power system that reducessite downtime. This is a semi$autonomous electrical generation system which links to the mainsto feed excess capacity back to the local mains electrical grid . !ecause the local system is phasematched, electricity can be drawn from the mains grid in the situation of a generating shortfall ordischarge in batteries

The %ower generating !TS would not require a diesel generator. The solar panels would capture#irect Current electricity which is then passed to a grid tied inverter . The inverter monitors thealternating current mains supply waveforms and generates electricity that is phase matched. The#C electrical system is attached to the mains via this mechanism.
http://en.wikipedia.org/wiki/Mainshttp://en.wikipedia.org/wiki/Grid_(electricity)http://en.wiktionary.org/wiki/shortfallhttp://en.wikipedia.org/wiki/Inverter_(electrical)http://en.wikipedia.org/wiki/Grid_(electricity)http://en.wiktionary.org/wiki/shortfallhttp://en.wikipedia.org/wiki/Inverter_(electrical)http://en.wikipedia.org/wiki/Mains


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&igure '( %ower "enerating !TS )rchitecture

*n the event of a power fault, the robust power generating base station system becomes grid$independent by using a battery bank to provide stored power. *n this way we can ensure that the!TS, communications equipment or other +critical loads are not unexpectedly shut down, thusavoiding data loss, equipment damage, and other problems. This +hybrid approach will both fixlong$term energy costs and provide security.

!OTIVATION AND BAC"GRO#ND O$ ST#DY

%ower outages are currently the ma-or cause unavailability of !TS and ode! units. *n theremote off$ grid areas, generator mechanical faults contribute significantly to this downtime.This results in frequent disruption of service and subsequent revenue loss.

"enerators work by converting mechanical energy to electrical energy. /hen the generator produces more electrical than the power required to charge the #C batteries, then the excess power is wasted. This results in unnecessary excess cost and wastage of energy. There wastherefore a need to come up with a more power efficient design that did not have highmaintenance costs such as servicing and refuelling.

Zimbabwe is geographically located in the Savannah region, which has one of the highestaverage sun light hours per day and intensity levels in the world. The climate in Zimbabwe istypically tropical0 moderated by altitude0 rainy season 1 ovember to arch2. The terrain( mostlyhigh plateau with higher central plateau 1high veld20 mountains in east, which are conducive forsolar power generation.

Taking into consideration the vast number of !TS sites spatially located within the national gridcoverage across the country, the total amount of power generating using this method would be


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significant not only to serve the purpose of maintaining the site up but also to reduce loadshedding .3sing a simplified approach for interconnecting and metering on$site renewablegenerating facilities, telecommunication service providers can use excess solar electricgeneration to offset utility$purchased electricity on a monthly or annul basis by means of aconcept known as net metering. This concept would be able to help alleviate the current national

power crisis, by contributing excess power back to the grid and in the process generatingrevenue.

)dvantages of the %ower "enerating !ase Station

4xcess electricity can be sold to mains.

4lectrical shortfall can be bought from mains.

!TS and ode! units are already usually located where there is a line of sight vision toother sites, implying that they are normally in an open and elevated area, which is also theideal environment for the solar systems

o running costs e.g. fuel resulting in power savings

o moving parts, thereby minimi5ing mechanical failures

o wasted energy, 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

o power loss due to inductance

!ill 6eduction

"reen 4nergy

!ETHODOLOGY

This pro-ect is going to be simulated by using a grid tied inverter inter$connecting to a miniaturesolar panel system and the national power grid. ) "raphical 3ser *nterface will compute the net

power transfer between the solar system and the grid in real time using the generic k/hcalibration.

Solar photovoltaic cells convert sunlight to direct current electricity. #irect Current electricity isthen passed to an inverter which is grid tied. The inverter monitors the alternating current mains
http://en.wiktionary.org/wiki/shortfallhttp://en.wikipedia.org/wiki/Inverter_(electrical)http://en.wikipedia.org/wiki/Grid_tie_inverterhttp://en.wiktionary.org/wiki/shortfallhttp://en.wikipedia.org/wiki/Inverter_(electrical)http://en.wikipedia.org/wiki/Grid_tie_inverter


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supply waveforms and generates electricity that is phase matched. The #C electrical system isattached to the mains via this mechanism as shown in the figure below.

)s a solar %7 system starts generating electricity, it first goes to meeting the on$site electric

demand at the !ase Station, slowing down the power being supplied by the grid. *t is verycommon that later on in the day the solar %7 system may produce more power than what isneeded at the site, at which point the +excess electricity will automatically back feed throughthe bi$directional meter, based on the signal from the control circuit. !ecause the local system is

phase matched, electricity can be drawn from the mains in the situation of agenerating shortfall or discharge in batteries. ) 8ava based "3* metering system will thenaccount for the overall power usage.

/hen there is load shedding or grid power is lost for some reason, the inverter activates atransfer switch which opens its connection to the grid. This keeps the inverter from trying to

power other devices in the grid, as well as keep energy off the power lines so utility workersdon9t get shocked.

The inverter also converts the dc power to ac power when feeding back to the grid.*nterfacing:interconnection with the grid is done through a circuit breaker on the main electricservice panel. The solar panels will be implemented in a fixed tilt position as part of the !TSequipment shade roofing.

AI! AND OB%ECTIVES O$ THE RESEARCH

The aim of the pro-ect is to use the sun9s energy to create a robust power system that reduces sitedowntime, cuts running costs and possibly even create revenue. The main ob-ective is to be ableto fully utili5e grid and backup power system in order to get the best of both in a cheap andeffective manner that not only helps to alleviate the national power crisis but also contributes to acleaner environment and less equipment downtime.
http://en.wiktionary.org/wiki/shortfallhttp://en.wiktionary.org/wiki/shortfall


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WOR" PLAN .

TI!E LINE ACTIVITY"EY ESTIONS TO BE

ANSWERED

!'r()

;ayout design

completion of research proposal

A*ril#esign )C$#C conversioncircuitry and line monitoringmechanism

!'+%rogram the "3* and test withdummy input.

%, e;ayout and wiring.)ssemble hardwarecomponents and software

%,l+Testing of hardwarecomponents and softwarecompatibility

Se*.e/0erTesting of hardwarecomponents and software

O(.o0er /att '= 7 mono$crystalline solar %anel:#C %ower Supply

Charge controller circuit

'= 7olt ;ithium *on !attery

Circuit board

;aptop computer

S%?@> microcontroller

6esistors and capacitors


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Circuit board wires

Soldering iron

Soldering gun

7isual Studio software

Re ere (es

http(::www.prnewswire.com:news$releases:off$grid$power$for$mobile$base$stations$$$renewable$and$alternative$energy$sources$for$remote$mobile$telecommunications$global$market$analysis$and$forecasts$'AA'AB ''

Dff$"rid %ower for obile !ase Stations $ 6enewable and )lternative 4nergy Sources for6emote obile Telecommunications( "lobal arket )nalysis and &orecasts$ avigant %ike6eport =>'=
http://www.prnewswire.com/news-releases/off-grid-power-for-mobile-base-stations---renewable-and-alternative-energy-sources-for-remote-mobile-telecommunications-global-market-analysis-and-forecasts-188185711http://www.prnewswire.com/news-releases/off-grid-power-for-mobile-base-stations---renewable-and-alternative-energy-sources-for-remote-mobile-telecommunications-global-market-analysis-and-forecasts-188185711http://www.prnewswire.com/news-releases/off-grid-power-for-mobile-base-stations---renewable-and-alternative-energy-sources-for-remote-mobile-telecommunications-global-market-analysis-and-forecasts-188185711http://www.prnewswire.com/news-releases/off-grid-power-for-mobile-base-stations---renewable-and-alternative-energy-sources-for-remote-mobile-telecommunications-global-market-analysis-and-forecasts-188185711http://www.prnewswire.com/news-releases/off-grid-power-for-mobile-base-stations---renewable-and-alternative-energy-sources-for-remote-mobile-telecommunications-global-market-analysis-and-forecasts-188185711http://www.prnewswire.com/news-releases/off-grid-power-for-mobile-base-stations---renewable-and-alternative-energy-sources-for-remote-mobile-telecommunications-global-market-analysis-and-forecasts-188185711

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