Ib qho ntawm cov laj thawj tseem ceeb tshaj plaws rau kev suav av thiab kev teeb tsa yog tias nws tiv thaiv tib neeg, khoom siv hauv tsev los ntawm overvoltage. Yog tias dheev xob laim tawm hauv tsev los yog vim qee yam muaj zog hauv lub network, tab sis tib lub sijhawm cov hluav taws xob hauv av, tag nrho cov hluav taws xob ntau dhau yuav nkag mus rau hauv av, txwv tsis pub yuav muaj qhov tawg uas tuaj yeem rhuav tshem txhua yam. hauv nws txoj kev.
khoom siv tiv thaiv hluav taws xob
Kev loj hlob ntawm kev siv hluav taws xob hauv txhua qhov chaw ntawm lub neej, hauv tsev thiab tom haujlwm, yuav tsum muaj cov cai tswj kev nyab xeeb rau tib neeg lub neej. Ntau lub teb chaws thiab thoob ntiaj teb cov qauv tswj hwm cov kev xav tau ntawm kev tsim hluav taws xob los xyuas kom muaj kev nyab xeeb ntawm tib neeg, tsiaj txhu thiab khoom siv thaum siv cov khoom siv hluav taws xob.
Cov khoom siv tiv thaiv hluav taws xob tau teeb tsa thaum lub sijhawm tsim kho vaj tse thiab pej xeem cov tsev yuav tsum tau kuaj xyuas tsis tu ncua kom ntseeg tau tias kev ua haujlwm ruaj khov rau ntau xyoo. Kev ua txhaum cai ntawm kev nyab xeeb hauv cov tshuab hluav taws xob tuaj yeem muaj qhov tsis zoo: kev hem thawj rau tib neeg lub neej, kev puas tsuaj ntawm cov khoom lossiskab mob kev puas tsuaj.
Cov cai tswj kev nyab xeeb tau teeb tsa cov kev txwv saum toj no rau kev nyab xeeb tib neeg kev sib cuag nrog cov chaw nyob: 36 VAC hauv cov tsev qhuav thiab 12 VAC hauv cov chaw ntub dej.
YGrounding system
Earthing system yog ib qho tseem ceeb ntawm cov cuab yeej siv rau txhua lub tsev, yog li nws yog thawj qhov kev teeb tsa hluav taws xob uas yuav tsum tau nruab rau hauv qhov chaw tshiab. Lub sij hawm grounding yog siv nyob rau hauv hluav taws xob engineering rau lub hom phiaj txuas hluav taws xob Cheebtsam rau lub ntiaj teb.
Kev tiv thaiv hauv av tiv thaiv tib neeg los ntawm hluav taws xob poob siab thaum kov cov khoom siv hluav taws xob thaum muaj kev ua haujlwm tsis zoo. Masts, laj kab, khoom siv xws li cov kav dej lossis cov kav dej yuav tsum tau txuas nrog kev tiv thaiv cable los ntawm kev txuas mus rau lub davhlau ya nyob twg lossis qhov chaw hauv av.
Teeb meem ntawm kev tiv thaiv kev ua haujlwm
Kev ua haujlwm hauv av tsis muaj kev nyab xeeb raws li lub npe qhia, es tsis txhob ua haujlwm tsis cuam tshuam ntawm cov tshuab hluav taws xob thiab khoom siv. Kev ua haujlwm hauv av dissipates tam sim no thiab lub suab nrov rau lub ntiaj teb sim adapters, kav hlau txais xov, thiab lwm yam khoom siv uas tau txais xov tooj cua nthwv dej.
Lawv txiav txim siab txog qhov muaj peev xwm siv tau ntawm cov khoom siv hluav taws xob thiab cov khoom siv thiab yog li tiv thaiv ntau yam haujlwm tsis zoo hauv cov tsev ntiag tug, xws li TV lossis lub teeb flickering. Kev ua haujlwm hauv av tsis tuaj yeem ua haujlwm tiv thaiv.
Txhua qhov kev xav tau rau kev tiv thaiv hluav taws xob tuaj yeem pom hauv cov qauv hauv tebchaws. Tsim kom muaj kev tiv thaiv lub ntiaj teb yog qhov tseem ceeb thiab yog li ntawd ib txwm ua qhov tseem ceeb ntawm kev ua haujlwm.
Qhov kawg tiv thaiv ntawm cov khoom tiv thaiv
Hauv lub kaw lus uas muaj kev nyab xeeb rau tib neeg, cov cuab yeej tiv thaiv yuav tsum ua haujlwm sai li sai tau thaum qhov hluav taws xob tsis raug hauv qhov system nce mus txog tus nqi uas tuaj yeem ua rau muaj kev phom sij rau lawv. Txhawm rau xam qhov ntsuas no, koj tuaj yeem siv cov ntaub ntawv ntsuas hluav taws xob saum toj no, xaiv tus nqi nruab nrab U=25 VAC.
Cov hluav taws xob hluav taws xob tam sim no tau teeb tsa hauv thaj chaw nyob yuav tsis nquag mus rau lub ntiaj teb kom txog rau thaum qhov luv luv tam sim no mus txog 500 mA. Yog li ntawd, raws li Ohm txoj cai, nrog U=R1 R=25 V / 0.5 A=50 ohms. Yog li ntawd, txhawm rau tiv thaiv kev nyab xeeb ntawm tib neeg thiab cov cuab yeej cuab tam, lub ntiaj teb yuav tsum muaj kev tiv thaiv tsawg dua 50 ohms, lossis R earth<50.
Electrode kev ntseeg tau yam
Raws li lub xeev cov qauv, cov ntsiab lus hauv qab no tuaj yeem suav tias yog electrodes:
- vertically ntxig steel pawg lossis kav dej;
- kab rov tav nteg steel strips lossis xaim;
- recessed hlau daim hlau;
- hlau rings tso nyob ib ncig ntawm lub hauv paus los yog embedded nyob rau hauv lub hauv paus.
Cov kav dej thiab lwm yam hauv av steel engineering tes hauj lwm (yog tias muaj kev pom zoo nrog cov tswv).
Kev ntseeg tau hauv av nrog kev tiv thaiv tsawg dua 50 ohms nyob ntawm peb yam:
- Vim av.
- Hom thiab av tiv thaiv.
- Ground line resistance.
Kev suav ntawm cov cuab yeej hauv av yuav tsum pib nrog kev txiav txim siab ntawm cov av tiv thaiv. Nws nyob ntawm cov duab ntawm cov electrodes. Lub ntiaj teb resistivity r (Greek tsab ntawv Rho) yog qhia nyob rau hauv ohm meters. Qhov no sib raug rau qhov theoretical tsis kam ntawm 1 m grounding cylinder 2, uas nws hla ntu thiab qhov siab yog 1 m. tau siab dua). Av resistivity piv txwv hauv Ohm-m:
- marshy av ntawm 1 txog 30;
- loess av ntawm 20 txog 100;
- humus los ntawm 10 txog 150;
- quartz xuab zeb los ntawm 200 txog 3000;
- soft limestone los ntawm 1500 txog 3000;
- nyom av ntawm 100 txog 300;
- pob zeb av tsis muaj zaub - 5.
Kev txhim kho cov khoom siv hauv av
Lub voj hauv av yog mounted los ntawm cov qauv uas muaj cov hlau electrodes thiab txuas strips. Tom qab muab tso rau hauv av, cov cuab yeej txuas nrog lub vaj huam sib luag hluav taws xob hauv tsev nrog cov xaim lossis cov hlau zoo sib xws. Cov av noo cuam tshuam rau qib kev tso kawm ntawm cov qauv.
Nws muaj qhov sib txawv ntawm qhov ntev ntawm rebar thiab qib dej hauv av. Qhov siab tshaj plaws ntawm qhov chaw tsim kho yog los ntawm 1 m txog 10 m. Electrodes rau kev xam hauv av yuav tsum nkag mus rau hauv av hauv qab ntawm cov av khov kab. Rau cov tsev, lub voj voog yog mounted siv cov khoom siv hlau: cov kav dej, kev txhim kho du, lub kaum sab xis steel, I-beam.
Lawv cov duab yuav tsum tau yoog rau qhov tob nkag mus rau hauv av, qhov chaw hla ntawm qhov kev txhawb nqa yog ntau tshaj 1.5 cm2. Qhov cuab lub zog yog muab tso rau hauv ib kab los yog nyob rau hauv daim ntawv ntawm ntau yam duab, uas ncaj qha nyob ntawm seb qhov tseeb qhov chaw ntawm lub site thiab muaj peev xwm mounting ib tug tiv thaiv ntaus ntawv. Cov tswv yim nyob ib puag ncig ntawm cov khoom siv feem ntau yog siv, txawm li cas los xij, cov qauv duab peb sab hauv av tseem yog qhov feem ntau.
Txawm hais tias qhov kev tiv thaiv tuaj yeem ua rau nws tus kheej siv cov khoom siv, ntau tus neeg tsim vaj tsev yuav cov khoom siv hauv tsev. Txawm hais tias lawv tsis pheej yig, lawv yooj yim rau nruab thiab siv tau ntev. Feem ntau, xws li cov khoom siv muaj tooj liab-plated electrodes 1 m ntev, nruab nrog ib tug threaded kev twb kev txuas rau mounting.
tag nrho streak suav
Tsis muaj txoj cai dav dav rau kev suav cov naj npawb ntawm qhov thiab qhov ntev ntawm cov kab hauv av, tab sis qhov tso tawm ntawm cov xau tam sim no yog nyob ntawm qhov ntu ntu ntawm cov khoom, yog li rau txhua yam khoom siv., qhov luaj li cas ntawm daim kab xev hauv av yog xam ntawm qhov tam sim no uas yuav nqa los ntawm lub strip no.
Yuav xam lub voj hauv av, qhov xau tam sim no yog thawj zaug suav thiab txiav txim siab strip loj.
Rau cov khoom siv hluav taws xob feem ntau xws li transformer,diesel generator, thiab lwm yam., qhov loj ntawm qhov nruab nrab hauv av sawb yuav tsum yog xws li tias nws tuaj yeem tswj cov khoom nruab nrab ntawm cov khoom siv no.
Piv txwv li, rau 100kVA transformer, tag nrho cov khoom thauj tam sim no yog li 140A.
Cov hlua txuas txuas yuav tsum muaj peev xwm nqa tau yam tsawg 70A (nruab nrab tam sim no), uas txhais tau hais tias 25x3mm strip yog txaus los nqa tam sim no.
Ib lub strip me me yog siv los ua hauv av, uas tuaj yeem nqa tau tam sim no ntawm 35 A, muab 2 lub ntiaj teb pits siv rau txhua yam khoom los tiv thaiv kev tiv thaiv. Yog hais tias ib lub strip yuav siv tsis tau vim yog corrosion, uas ua rau lub siab ncaj ncees ntawm lub Circuit Court, cov dej ntws ntws los ntawm lwm qhov system, muab kev tiv thaiv.
Xam txog tus lej ntawm cov kav dej tiv thaiv
Cov av tiv thaiv ntawm ib qho hluav taws xob ib leeg lossis lub raj yog xam raws li:
R=ρ / 2 × 3, 14 × L (log (8xL / d) -1)
Qhov twg:
ρ=Av tsis kam (ohmmeter), L=Electrode ntev (meter), D=Electrode txoj kab uas hla (meter).
Kev suav av (piv txwv):
Xaiv qhov kev tiv thaiv ntawm av insulating pas nrig. Nws muaj qhov ntev ntawm 4 meters thiab txoj kab uas hla ntawm 12.2 hli, ib qho kev nqus ntawm 500 ohms.
R=500 / (2 × 3, 14 × 4) x (Log (8 × 4 / 0, 0125) -1)=156, 19 Ω.
Cov av tiv thaiv ntawm ib tus pas nrig lossis lub raj electrode yog xam raws li hauv qab no:
R=100xρ / 2 × 3, 14 × L (log (4xL / d))
Qhov twg:
ρ=Av tsis kam (ohmmeter), L=Electrode ntev (cm), D=Electrode txoj kab uas hla (cm).
Definitiongrounding structure
Kev xam cov av ntawm ib qho kev teeb tsa hluav taws xob pib nrog kev txiav txim siab ntawm cov kav dej hauv av nrog txoj kab uas hla ntawm 100 hli, 3 meters ntev. Lub kaw lus muaj qhov txhaum tam sim no ntawm 50 KA rau 1 thib ob thiab hauv av resistivity ntawm 72.44 ohms.
tam sim no qhov ntom ntom ntawm lub ntiaj teb electrode:
Pob. tso cai tam sim no ceev kuv=7.57 × 1000 / (√ρxt) A / m2
Pob. tso cai tam sim no ceev=7.57 × 1000 / (√72.44X1)=889.419 A / m2
Qhov chaw saum npoo ntawm ib txoj kab uas hla yog 100 hli. Luas=2 x 3, 14 L=2 x 3, 14 x 0.05 x 3=0.942 m2
Pob. tam sim no dissipated los ntawm ib qho av yeeb nkab=tam sim no ceev x Electrode nto cheeb tsam.
Max. tam sim no dissipated los ntawm ib tug grounding yeeb nkab=889.419x 0.942=838A, Number of earth pipe yuav tsum=Fault current / Max.
Ntau cov yeeb nkab hauv av xav tau=50000/838=60 daim.
Ntiaj teb yeeb nkab tsis kam (insulated) R=100xρ / 2 × 3, 14xLx (log (4XL / d))
Ground yeeb nkab tsis kam (insulated) R=100 × 72.44 / 2 × 3 × 14 × 300 × (log (4X300 / 10))=7.99 Ω / Pipe
Txhua qhov kev tiv thaiv ntawm 60 daim av=7.99 / 60=0.133 Ohm.
av strip resistance
Ground strip resistance (R):
R=ρ / 2 × 3, 14xLx (log (2xLxL / wt))
Ib qho piv txwv ntawm kev ntsuas lub voj hauv qab yog muab hauv qab no.
Xaiv ib kab 12 hli dav, 2200 meters ntev,faus rau hauv av ntawm qhov tob ntawm 200 hli, cov av resistivity yog 72.44 ohms.
Ground strip resistance (Re)=72, 44 / 2 × 3, 14x2200x (log (2x2200x2200 /.2x.012))=0, 050 Ω
Los ntawm cov saum toj no tag nrho tsis kam ntawm 60 daim ntawm cov kav dej hauv av (Rp)=0.133 ohms. Thiab qhov no yog vim qhov ntxhib hauv av sawb. Ntawm no net earth resistance=(RpxRe) / (Rp + Re)
Net resistance=(0.133 × 0.05) / (0.133 + 0.05)=0.036 Ohm
av impedance thiab tus naj npawb ntawm electrodes ib pab pawg (kev sib txuas ua ke). Nyob rau hauv cov ntaub ntawv uas ib tug electrode tsis txaus los muab lub ntiaj teb no tiv thaiv, ntau tshaj ib tug electrode yuav tsum tau siv. Kev sib cais ntawm cov electrodes yuav tsum yog li 4 m. Qhov sib xyaw ua ke ntawm cov electrodes thaum uas tig mus yog ib qho kev ua haujlwm ntawm ntau yam xws li tus lej thiab kev teeb tsa ntawm cov electrode. Tag nrho cov tsis kam ntawm ib pawg ntawm electrodes nyob rau hauv ntau yam configuration raws li:
Ra=R (1 + λa / n), where a=ρ / 2X3.14xRxS
Qhov twg: S=Qhov nrug ntawm kev kho qia (meter).
λ=Factor pom hauv cov lus hauv qab no.
n=Number of electrodes.
ρ=Av tsis kam (Ohmmeter).
R=Kev tiv thaiv ntawm ib tus pas nrig hauv rwb thaiv tsev (Ω).
| Cov khoom rau cov kab hluav taws xob sib luag hauv kab | |
| Number of electrodes (n) | Factor (λ) |
| 2 | 1,0 |
| 3 | 1,66 |
| 4 | 2, 15 |
| 5 | 2,54 |
| 6 | 2, 87 |
| 7 | 3.15 |
| 8 | 3, 39 |
| 9 | 3,61 |
| 10 | 3,8 |
Xaiv cov av ntawm cov hluav taws xob sib npaug sib npaug nyob ib ncig ntawm lub hollow square, xws li ib puag ncig ntawm lub tsev, cov kev sib npaug saum toj no yog siv nrog tus nqi ntawm λ coj los ntawm cov lus hauv qab no. Rau peb rods nyob rau hauv ib tug equilateral daim duab peb sab los yog nyob rau hauv ib tug L-tsim, tus nqi λ=1, 66
| Yam rau hollow square electrodes | |
| Number of electrodes (n) | Factor (λ) |
| 2 | 2,71 |
| 3 | 4,51 |
| 4 | 5, 48 |
| 5 | 6, 13 |
| 6 | 6, 63 |
| 7 | 7,03 |
| 8 | 7, 36 |
| 9 | 7, 65 |
| 10 | 7, 9 |
| 12 | 8, 3 |
| 14 | 8,6 |
| 16 | 8,9 |
| 18 | 9, 2 |
| 20 | 9, 4 |
Kev suav cov voj tiv thaiv hauv av rau hollow squares yog ua raws li cov qauv ntawm tag nrho cov electrodes (N)=(4n-1). Txoj cai ntawm tus ntiv tes xoo yog tias cov pas nrig sib npaug yuav tsum tau ncua ntev li ob zaug kom tau txais txiaj ntsig zoo ntawm cov electrodes ntxiv.
Yog tias qhov sib cais ntawm cov electrodes ntau dua li lawv qhov ntev, thiab tsuas yog ob peb lub electrodes nyob rau tib lub sijhawm, ces qhov tshwm sim hauv lub ntiaj teb tuaj yeem suav nrog siv qhov sib npaug li niaj zaus rau kev ua haujlwm. Hauv kev xyaum, qhov ua tau zoo hauv lub ntiaj teb feem ntau yuav siab dua qhov xam tau.
Feem ntau, 4-electrode array tuaj yeem muab 2.5-3 zaug kev txhim kho.
Ib qho ntawm 8 electrodes feem ntau muab kev txhim kho ntawm tej zaum 5-6 zaug. Qhov kev tiv thaiv ntawm tus pas nrig hauv av yuav raug txo los ntawm 40% rau kab thib ob, 60% rau kab thib peb, 66% rau plaub.
Electrode xam piv txwv
Xaiv tag nrho cov kev tiv thaiv ntawm cov pas nrig hauv av 200 units nyob rau hauv parallel, ntawm 4m ncua sij hawm txhua, thiab yog tias lawv txuas nrog hauv ib lub xwmfab. Lub hauv paus yog 4meters thiab ib txoj kab uas hla ntawm 12.2 hli, nto kuj 500 ohms. Ua ntej, qhov kev tiv thaiv ntawm ib qho av ib leeg yog xam: R=500 / (2 × 3, 14 × 4) x (Log (8 × 4 / 0, 0125) -1)=136, 23 ohms.
Tom ntej no, tag nrho cov kev tiv thaiv ntawm cov pas nrig hauv av nyob rau hauv tus nqi ntawm 200 units nyob rau hauv parallel: a=500 / (2 × 3, 14x136x4)=0.146 Ra (kab ua ke)=136.23x (1 + 10 × 0.146 / 200)=1.67 Ohm.
Yog cov pas nrig hauv av txuas nrog thaj tsam hollow 200=(4N-1), Ra (ntawm qhov khoob khoob)=136, 23x (1 + 9, 4 × 0, 146 / 200)=1, 61 Ohm.
Ground Calculator
Raws li koj tuaj yeem pom, kev suav hauv av yog cov txheej txheem nyuaj heev, nws siv ntau yam thiab cov qauv kev ua haujlwm nyuaj uas tsuas yog muaj rau cov kws tshaj lij kev cob qhia nrog cov software nyuaj.
Tus neeg siv tsuas tuaj yeem suav qhov ntxhib siv cov kev pabcuam online, piv txwv li, Allcalc. Yog xav paub ntxiv kom raug, koj tseem yuav tau hu rau lub koom haum tsim.
Allcalc online laij lej yuav pab tau koj sai thiab raug xam cov kev tiv thaiv hauv av hauv ob txheej av uas muaj cov av ntsug.
Xaiv ntawm qhov system parameters:
- txheej saum av yog xuab zeb moistened heev.
- Climatic coefficient- 1.
- txheej hauv qab ntawm av yog xuab zeb moistened.
- Tus naj npawb ntawm cov av ntsug - 1.
- Top av tob H (m) - 1.
- Vertical section length, L1 (m) - 5.
- Qhov tob ntawm kab rov tav h2 (m)- 0.7.
- Txoj hlua ntev, L3 (m) - 1.
- kab ntawm kab ntsug, D (m) - 0.025.
- Dav ntawm ntu kab rov tav txee, b (m) - 0.04.
- Electrical av resistance (ohm/m) - 61.755.
- Resistance ntawm ib ntu ntsug (Ohm) - 12.589.
- Length of the horizontal section (m) - 1.0000.
Kab rov tav grounding kuj (Ohm) - 202.07.
Xam txog kev tiv thaiv lub ntiaj teb ua tiav. Tag nrho cov tsis kam mus rau propagation ntawm hluav taws xob tam sim no (Ohm) - 11.850.
Ground muab cov ntsiab lus siv rau ntau qhov chaw hluav taws xob hauv qhov hluav taws xob. Ib qho ntawm cov laj thawj uas vim li cas hauv av yuav pab kom tus neeg muaj kev nyab xeeb yog lub ntiaj teb yog tus neeg xyuas pib loj tshaj plaws hauv ntiaj teb, thiab cov hluav taws xob ntau dhau ib txwm siv txoj hauv kev tsawg kawg nkaus. Los ntawm kev cog cov hluav taws xob hauv tsev, ib tus neeg tso cai rau cov dej ntws mus rau hauv av, uas cawm nws txoj sia thiab lwm tus txoj sia.
Yog tias tsis muaj lub tshuab hluav taws xob hauv tsev kom zoo, cov neeg siv khoom pheej hmoo tsis yog cov khoom siv hauv tsev nkaus xwb, tab sis lawv lub neej. Yog li ntawd, nyob rau hauv txhua lub tsev nws yog ib qho tsim nyog tsis yog tsuas yog tsim kom muaj kev sib txuas hauv av xwb, tab sis kuj yuav tsum saib xyuas txhua xyoo nws cov kev ua tau zoo siv cov cuab yeej ntsuas tshwj xeeb.
