Kev Xaiv Cov Khoom Siv Tiv Thaiv Surge Kev Xaiv rau PV Systems - Hom SPDs
Kev tsim hluav taws xob photovoltaic (PV) yog qhov tseem ceeb ntawm lub zog rov ua dua tshiab thiab muaj kev sib tw heev hauv kev lag luam piv rau kev tsim hluav taws xob ib txwm muaj. Cov kab ke PV me me faib tawm, xws li cov vaj huam sib luag hnub ci ntawm lub ru tsev, tab tom nrov zuj zus. Cov kab ke PV saum ru tsev muaj ob qho tib si AC thiab DC faib nrog cov hluav taws xob ncav cuag txog 1500V. Sab DC, tshwj xeeb tshaj yog cov vaj huam sib luag PV, tuaj yeem raug ncaj qha rau xob laim hauv thaj chaw muaj kev pheej hmoo siab, ua rau lawv yooj yim rau kev puas tsuaj los ntawm xob laim.
Kev tiv thaiv xob laim rau cov tsev muaj faib ua kev tiv thaiv sab nraud (Lightning Protection System, LPS) thiab kev tiv thaiv sab hauv (Surge Protective Measures, SPM), raws li kev pheej hmoo ntawm xob laim. Cov Khoom Siv Tiv Thaiv Surge (SPDs), ua ib feem ntawm kev tiv thaiv sab hauv, tiv thaiv kev hloov pauv hluav taws xob ib ntus los ntawm xob laim hauv huab cua lossis kev ua haujlwm hloov pauv. SPDs raug ntsia sab nraud cov khoom siv tiv thaiv thiab feem ntau ua haujlwm raws li hauv qab no: thaum tsis muaj surge hauv lub zog fais fab, SPD tsis cuam tshuam rau kev ua haujlwm ib txwm ntawm lub cev uas nws tiv thaiv. Thaum muaj surge tshwm sim, SPD muab impedance qis, diverting lub surge tam sim no los ntawm nws tus kheej thiab txwv lub voltage mus rau qib nyab xeeb. Tom qab surge tau dhau mus thiab txhua qhov tam sim no seem tau tuag lawm, SPD rov qab mus rau lub xeev impedance siab.
1. Qhov Chaw Teeb tsa ntawm Cov Khoom Siv Tiv Thaiv Surge (SPD)
Qhov chaw teeb tsa ntawm SPDs yog txiav txim siab raws li qib kev hem thawj ntawm xob laim thiab raws li lub tswv yim Lightning Protection Zones (LPZ) hauv IEC 62305. Transient overvoltages raug txo qis mus rau qib kev nyab xeeb, uas yuav tsum qis dua qhov voltage ntawm cov khoom siv tiv thaiv. Raws li tau piav qhia hauv Daim Duab, SPDs raug teeb tsa ntawm ciam teb ntawm cov cheeb tsam no, ua rau muaj lub tswv yim ntawm kev tiv thaiv ntau theem surge siv hauv cov kab ke qis-voltage. Rau cov kab ke PV, qhov kev tsom mus rau kev tiv thaiv xob laim los ntawm kev nkag mus los ntawm AC thiab DC sab, yog li tiv thaiv cov khoom tseem ceeb xws li inverters.
2. Cov Chav Kawm Ntsuas Cov Khoom Siv Tiv Thaiv Hluav Taws Xob (SPD)
Raws li IEC 61643-11, SPDs raug muab faib ua peb pawg kev xeem raws li hom hluav taws xob uas lawv tsim los tiv taus. Hom I kev xeem (cim ua T1) yog tsim los ua kom pom cov hluav taws xob ib nrab uas yuav raug coj mus rau hauv lub tsev. Cov no siv 10/350 µs waveform, raws li pom hauv Daim Duab blow, thiab feem ntau yog siv rau ntawm ciam teb ntawm LPZ0 thiab LPZ1 - xws li ntawm cov laug cam faib khoom loj lossis cov khoom siv hluav taws xob qis. SPDs rau qib no feem ntau yog hom voltage-switching, nrog rau cov khoom xws li cov raj xa roj lossis cov qhov hluav taws xob (piv txwv li, qhov hluav taws xob horn lossis qhov hluav taws xob graphite).
Kev xeem Hom II (T2) thiab Hom III (T3) siv cov impulses luv dua. Hom II SPDs feem ntau yog cov khoom siv txwv voltage uas siv cov khoom xws li cov hlau oxide varistors (MOVs). Lawv raug sim nrog lub nominal discharge current siv 8/20 µs current waveform (saib Daim Duab), thiab yog lub luag haujlwm rau kev txwv ntxiv qhov residual surge voltage los ntawm lub upstream protection device. Kev xeem Hom III siv lub combination wave generator nrog 1.2/50 µs voltage thiab 8/20 µs current impulse (saib Daim Duab hauv qab no), simulating surges ze rau cov khoom siv kawg.
3. Hom Kev Sib Txuas ntawm Cov Khoom Siv Tiv Thaiv Surge (SPDs)
Muaj ob hom kev tiv thaiv tseem ceeb tiv thaiv kev overvoltages ib ntus. Thawj hom yog kev tiv thaiv hom sib xws (CT1), uas yog tsim los tiv thaiv kev nce siab ntawm cov neeg ua hluav taws xob thiab PE (lub ntiaj teb tiv thaiv). Piv txwv li, xob laim tuaj yeem ua rau muaj hluav taws xob siab piv rau hauv av rau hauv ib lub kaw lus. Kev tiv thaiv hom sib xws pab txo qhov cuam tshuam ntawm cov kev cuam tshuam sab nraud, xws li xob laim, raws li tau piav qhia hauv qab no.
Qhov thib ob yog kev tiv thaiv hom sib txawv (CT2), uas tiv thaiv kev nce siab ntawm tus neeg xa xov kab (L) thiab tus neeg xa xov nruab nrab (N). Hom kev tiv thaiv no yog qhov tseem ceeb rau kev daws teeb meem sab hauv, xws li suab nrov hluav taws xob lossis kev cuam tshuam uas tsim tawm hauv lub kaw lus nws tus kheej, raws li pom hauv daim duab hauv qab no.
Los ntawm kev siv ib lossis ob qho tib si ntawm cov hom kev tiv thaiv no, cov kab ke hluav taws xob tuaj yeem tiv thaiv tau zoo dua los ntawm cov chaw muaj peev xwm nce siab, thaum kawg txhim kho lub neej ntev thiab kev ntseeg siab ntawm cov khoom siv txuas nrog.
Nws yog ib qho tseem ceeb uas yuav tsum nco ntsoov tias kev xaiv cov hom kev tiv thaiv SPD yuav tsum sib haum nrog lub kaw lus av hauv qhov chaw. Rau cov kab ke TN, ob qho tib si CT1 thiab CT2 hom kev tiv thaiv tuaj yeem siv tau. Txawm li cas los xij, hauv cov kab ke TT, CT1 tsuas yog siv tau rau sab qis ntawm RCD. Hauv cov kab ke IT—tshwj xeeb tshaj yog cov uas tsis muaj tus neeg hlau nruab nrab—CT2 kev tiv thaiv tsis siv tau. Qhov no yog qhov kev txiav txim siab tseem ceeb hauv cov kab ke faib khoom DC uas siv cov qauv av IT. Cov ntsiab lus tuaj yeem pom hauv lub rooj hauv qab no.
4. Cov Kev Ntsuas Tseem Ceeb ntawm Cov Khoom Siv Tiv Thaiv Surge (SPD)
Raws li tus qauv thoob ntiaj teb IEC 61643-11, cov yam ntxwv thiab kev sim ntawm SPDs txuas nrog rau cov kab ke faib hluav taws xob qis-voltage tau txhais, raws li pom hauv Daim Duab 7.
(1) Qib Kev Tiv Thaiv Hluav Taws Xob (Saum Toj)
Qhov tseem ceeb tshaj plaws hauv kev xaiv SPD yog nws qib kev tiv thaiv hluav taws xob (Saum), uas piav qhia txog kev ua tau zoo ntawm SPD hauv kev txwv qhov hluav taws xob ntawm cov terminals. Tus nqi no yuav tsum siab dua qhov siab tshaj plaws clamping voltage. Nws raug ncav cuag thaum tam sim no ntws los ntawm SPD sib npaug rau qhov nominal discharge tam sim no In. Qib kev tiv thaiv hluav taws xob xaiv yuav tsum qis dua qhov impulse withstand voltage Uw ntawm lub load. Thaum muaj xob laim ntaus, qhov hluav taws xob hla cov terminals SPD feem ntau khaws cia hauv qab Saum. Rau PV DC systems, qhov load feem ntau yog hais txog PV modules thiab inverters.
(2) Qhov Siab Tshaj Plaws Ua Haujlwm Txuas Ntxiv Mus (Uc)
Uc yog qhov siab tshaj plaws DC voltage uas tuaj yeem siv tas mus li rau SPD hom kev tiv thaiv. Nws raug xaiv raws li qhov ntsuas voltage thiab lub kaw lus grounding configuration thiab ua haujlwm ua qhov pib ua haujlwm ntawm SPD. Rau sab DC ntawm PV systems, Uc yuav tsum loj dua lossis sib npaug rau PV array's Uoc Max. Uoc Max hais txog qhov siab tshaj plaws qhib-circuit voltage ntawm cov terminals nyob thiab ntawm lub terminal nyob thiab av ntawm qhov chaw teem tseg ntawm PV array.
(3) Nominal Discharge Current (Hauv)
Qhov no yog tus nqi siab tshaj plaws ntawm 8/20 μs waveform tam sim no ntws los ntawm SPD, siv rau kev xeem Hom II thiab rau kev xeem ua ntej hauv Hom I thiab Hom IIIEC xav kom SPD tuaj yeem tiv taus tsawg kawg 19 qhov kev tso tawm ntawm 8/20 μs waveform tam sim no. Tus nqi In siab dua, lub neej SPD ntev dua, tab sis tus nqi kuj nce ntxiv.
(4) Tam sim no Impulse (Iimp)
Txhais los ntawm peb qhov kev ntsuas: qhov siab tshaj plaws tam sim no (Ipeak), tus nqi (Q), thiab lub zog tshwj xeeb (W/R), qhov tam sim no no yog siv rau hauv Hom I kev ntsuam xyuas. Tus qauv nthwv dej yog 10/350 μs.