My Home Photovoltaic PV Power System 光伏Word下载.docx
- 文档编号:21366838
- 上传时间:2023-01-30
- 格式:DOCX
- 页数:9
- 大小:132.29KB
My Home Photovoltaic PV Power System 光伏Word下载.docx
《My Home Photovoltaic PV Power System 光伏Word下载.docx》由会员分享,可在线阅读,更多相关《My Home Photovoltaic PV Power System 光伏Word下载.docx(9页珍藏版)》请在冰豆网上搜索。
gridtied"
PVsystem.
A"
PVsystemoperatesinconjunctionwithaconventionalelectricutilityfeed.IfthePVsystemproducesmorepowerthanneededtooperatelocalloads,theexcessis"
sold"
totheutility,runningtheelectricmeterbackwardsandgeneratingabillingcredit.WhenthelocalloadsaregreaterthanthepowergeneratedbythePVsystem,e.g.,atnightorwhenlargeloadsarebeingoperated,themeterrunsforward.
PVtechnologyismaturingrapidly,thoughthecostisstillnotlowenoughtocompetedirectlywithutilityelectricrates,evenwiththegovernmentsubsidies.SoImaintainnoillusionsthatI'
mdoingthistosavemoney.NoramIoneofthoseloonyY2Ksurvivalists.I'
mdoingitbecauseofalong-standinginterestinthetechnology.Ialsogetsomesidebenefits,suchasaUPS(uninterruptablepowersupply)thatcanrunmycomputersforhoursintheeventofapowerfailure.
SolarPanels
HereyoucanseethetwelveAstropowerAP1206solarpanelsonmyroof.TheywereinstalledbyCarlson'
sSolarofHemet,California.Theyareconfiguredasthreestringsoffourpanelseach.Eachpanelconsistsof36cellsproducinganominal12VDCunderload,soeachstringproducesanominal48V(theno-loadvoltageisconsiderablyhigher,about80V).
Theroofonwhichthepanelsaremountedslopestothesouth-southwestatabout20degrees.Ideallytheywouldfaceduesouth,butthatwouldhaverequiredmorecomplexmountingbrackets.Besides,itisfrequentlycloudyintheearlymorningshereinSanDiego,withthecloudsburningoffbylatemorning.Amorewesterlyorientationfavorstheafternoonwhenitismorelikelytobesunny.Italsofavorsproductionwhenelectricratesareattheirhighest(moreaboutthislater).
Thepanelcablingis10-gauge2-conductorTypeTCcable,moistureandsunlightresistant.Thecablespenetratetheroofinaconventionalweatherheadusedforutilityserviceentrances.Thecablinggoesin1"
flexconduittoaTraceTCB10PVCombinerBoxintheattic.Three#6wires(DC+,DC-andground)runfromthecombinerboxin1"
flextothegarage.
SystemElectronics
Thearraypowerentersthebackwallofmygarage,whereIinstalledaTraceSW4048sinewaveinverter,aTraceDCdisconnect,a48volt220amp-hourbatterybankusingTrojanT-105commoditygolfcartbatteries,andaCrusingEquipmentCompanyE-meterbatterymonitor.AconventionalACsubpanelontheinverteroutputfeedsbranchcircuitsaroundthehousewithvarious"
protected"
loads,suchasmycomputerandnetworkinggearandmyVCR(soIwon'
tlosemyprogramsintheeventofapowerfailure!
)
Hereyoucanseethebackwallofmygarage.Theconduitfromthearraysisattherightsideofthephoto;
itenterstheDCbreakerpanel(theuprightrectangularwhiteboxwithahorizontalgreenstripe).Afterpassingthroughcircuitbreakers,thearraypowerflowstoaTracePhotovoltaicGroundFaultProtector,anoverpricedandlargelyuselessdevicethatisnonethelessrequiredbysection690-5oftheNationalElectricalCode.ThePVGFPismountedinthegreyboxatthelowerright.
AfterpassingthroughthePVGFP,thearraypowerflowsthrougharelayinthePVGFPmountingbox.Thisrelayopenswheneverthebatteryvoltageexceedsaprogrammedlevel.
Undernormaloperation,therelayisalwaysclosedasanyexcesspowerfromthearraysisautomaticallysoldbacktotheutility.Thiskeepsthebatteryvoltagefromeverreachingthepointthatwouldopentherelay.Butthisrelayisimportanttoprotectmybatteriesintheeventthegridisnotavailableasa"
diversionload"
.E.g.,theinvertercouldfail,acircuitbreakercouldopen,orthegridcouldgodown.
Therelaydoeslacktwofeaturesofasolidstatecontroller:
amulti-stagebatterychargingprogram,andanighttimecutout.Becausemysystemisgridtied,themultistagebatterychargerprogramisnotveryusefultome.Mybatteriesarenormallyfullycharged,andiftheyaren'
t(e.g.,afterapowerfailure)theTraceinverteralreadyhasamultistagebatterycharger.ThelackofanighttimedropoutmeansthatunlessIopenthearraybreakeratsundown,I'
llgetabout200mA(about10watts)ofbackfeedfromthebatteryintothepanelsatnight.Icouldstopthiswithdiodesonthepanelfeeds,butthepowerlossissosmallthatIwouldprobablylosemoreduringthedayinthevoltagedropacrossthediodesthanI'
dsaveatnight.Therelaycoilitselfdrawsanother2-3watts.
Thebatteriesareinthebrownboxatthebottomcenterofthephoto.Imadetheboxoutof3/4"
MDF(mediumdensityfiberboard).Thetopslopesuptowardthebacktoencouragehydrogengasproducedbythebatteriestoflowintothe3"
ventlineconnectedtotheleftrearcornerofthetopofthebox.Thislinecarriesthehydrogentojustbelowaturbineventintheroofofmygarage.(Personally,Ibelievehydrogeninagarageisalotlessdangerousthanordinarygasoline;
whilegasolinevaporscollectandlingernearthefloor,hydrogenrapidlydissipates.Buttheinspectormademedoitanyway.)
ThebatteryisconnectedbackthroughtheDCbreakerboxthroughabig175AcircuitbreakertotheTraceinverter,thebigwhiteboxjustabovetheDCbreakerpanel.Becausetheinvertercancarrysubstantialpower,thecablesherearequiteheavy(2/0).
ThetwogreyboxesatthetopcenterofthepictureareconventionalACsubpanels.TheoneontheleftisanexistinggaragesubpanelIputinwhenIgotmyEV1andIinstalledtheMagnechargerEVcharger(ontheleftsideofthepicture).Theright-handsubpanelisconnectedtotheoutputoftheinverterandsupportsthespecialbranchcircuitsforthe"
loads(protectedagainstpowerfailure,thatis).
Theblackcordhangingfromtheleftsideoftheinverterisforagenerator.Intheeventofanextendedpoweroutage,Icansetupaportablegeneratoranduseittosupplementthepowerfromthesolararraystooperatetheprotectedloadsandtorechargebatteries.
Batteries
Here'
saviewlookingdownintothebatterybox.
Theinterconnectsare2/0buildingwirefromHomeDepot.Itwasrelativelycheap($0.85/foot)butarealpaintoworkwith;
verystiffandunforgiving.Thecablesleadingoutoftheboxontherightsideare2/0flexible"
boatcable"
.Itismucheasiertoworkwith,butitisveryexpensive($7.50/footatBoat/US,alocalmarinestore).Theyellowcableisforabatterytemperaturesensoraffixedtothebatteryontherightrear.Thebluewiretapsthebatteryatthemid-pointtosupply24VDCforthee-meter;
notethein-linefuseholdernearthebatteryterminal.Althoughtappingabatterylikethiscantheoreticallycausethepacktobecomeunbalanced,inpracticethedrainlowenoughthattheimbalanceisisquicklycorrectedbyroutinebatteryequalization.
Thebottomofthebatteryboxconsistsofthree2x6swithgapsbetweentoallowairtocirculateupfromventilationholesdrilledinthesidesofthebox.Undertheboxisasheetofpolyethylenetocatchanyacidspills.BeforeputtinginthebatteriesIsprinkledaboxofbakingsodaintotheboxtohelpneutralizeanyspilledacid.
DCwiring
sacloserlookattheDCbreakerpanel:
TheE-meterismountedina2"
knockoutontheupperleftside.The175Ainverterbreakerisinthecenterofthebox.Thearraycomesinontherightsidethrough1"
flexibleconduit,andthe2/0cablestotheinverterleavein2"
PVContheupperright.Notethewhitetapearoundoneoftheinvertercablesindicatingthatitisagroundedneutral.Itisconnectedtoa500A50mVbatterycurrentshuntfortheE-meter.Totherightofthesametapedcableisanegativebusbar.Thearraynegativeleadsconnecthere.
Thethreearrayhotleads(red)goto15ADCcircuitbreakersmountedattheupperright,upperleftandlowerleft.ThecombinedoutputofthesethreebreakerspassesdowntothePVGFPmountedinthegreyboxatthelowerright.
PVGroundFaultProtector
Thisisthegroundfaultdetector.ItisnothingmorethantwomechanicallygangedDCcircuitbreakers.Theoneontherighttripsat1amp;
theoneontheleftisactuallyaswitchratedat100amps.The1-ampbreakerisshuntedbya50kohmresistor.Whenclosed,the1-ampbreakerconnectsthenegativeDCbus(thewhitewire,signifyingthatitisthesystemneutral)toearthground(thegreenwirewithayellowstripe);
thisistheonlyplacewheretheDCneutralisgrounded.The100Aswitchconnectsthecombinedarrayoutputtotheinputofthechargecontroller.
Theblackdevicehangingoffoneoftheredwiresisaclamp-onDCammetermeasuringarrayoutputcurrent.
Intheeventofafaultbetweenapositivelead(batteryorarray)togroundinexcessof1amp,the1ampbreakerwilltripandopenthe100Aswitchwithit.Thiswillinterruptthegroundfaultexceptforasmallamountofcurrentthatwillcontinuet
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- My Home Photovoltaic PV Power System 光伏
链接地址:https://www.bdocx.com/doc/21366838.html