Rau Kev Kho & Kev Tiv Thaiv Cov Kws Ua Haujlwm, muaj cov FAQ muaj txiaj ntsig zoo txog Secondary Burden & 10% Kev Ntsuam Xyuas Kev Ntsuas Kab Mob. Los ntawm lawv, peb tuaj yeem kawm paub ntau ntxiv txog CT PT ntsuas.
FAQ 1: Dab tsi yog "Burden" hauv cov ntsiab lus yooj yim?
Q: Vim li cas peb piv CT Burden rau lub tsheb thauj khoom?
A: CT ua raws li lub tsheb thauj khoom; Burden yog "roughness" thiab "qhov hnyav" ntawm txoj kev (xaim / relays). High impedance yuam CT los tsim ntau qhov hluav taws xob, ua rau cov tub ntxhais saturation.
Physics:
• High Burden=High Secondary Voltage (Vs=Yog * Z).
• Siab Vs=Siab Sib Nqus Flux hauv cov tub ntxhais.
Qhov tshwm sim: Lub nra hnyav ua rau CT " dag" thaum lub sijhawm ua txhaum los ntawm kev tshaj tawm tam sim no tsawg dua li qhov tseeb.
FAQ 2: Rated Burden vs. Qhov tseeb Load
Q: Kuv qhov tseeb Burden yog 2.5 VA, tab sis daim ntawv teev npe hais tias 30 VA. Qhov no puas yog qhov teeb meem?
A: Tsis yog, qhov no yog qhov zoo tagnrho. Rated Burden yog lub peev xwm siab tshaj plaws; Qhov tseeb Burden yog qhov hnyav tam sim no. Cov npoo loj ua kom raug thiab ruaj khov.
Modern Shift:
• Laus electromagnetic relays siv 10-15 VA.
• Niaj hnub nimno digital relays siv <0.5 VA.
Tus nqi: Qhov kev nyab xeeb loj no ua rau CTs ntau dua kev ntseeg siab hauv cov chaw digital niaj hnub.
FAQ 3: Qhov tseem ceeb ntawm "10% yuam kev Curve"
Q: Vim li cas 10% yog "Lub Neej-Kab" rau kev tiv thaiv chav kawm CTs?
A: Relays ua haujlwm kom raug yog tias qhov yuam kev yog <10%. Yog tias CT saturates thiab qhov yuam kev hits 50-70%, lub relay yuav tsis pom qhov txhaum, thiab cov khoom tawg.
Kev txiav txim siab Matrix:
• yuam kev <10%: Relay mus ncig ua si raws sij hawm. ✅
• yuam kev > 10%: Relay "dig muag" los ntawm saturation. ❌
Lus Txhais: Qhov nkhaus taw qhia qhov Maximum Allowed Burden vs. Primary Fault Current.
FAQ 4: Predictive Testing - Pom 10,000A yav tom ntej
Q: Yuav ua li cas tus neeg soj ntsuam paub qhov 10% nkhaus yam tsis muaj kev txhaj tshuaj loj?
A: Nws siv lej Extrapolation raws li qhov tsis yog -linear "Magnetic Model" ntawm CT.
Logic Cav:
❶ Ntsuas Core Saturation: Ua thaum Hnub 2 (Kev sim siab).
❷ Ntsuas Field Burden: Ntsuas qhov tseeb ntawm cov hlau tsis kam.
❸ Simulation: Lub computer xam Vs xav tau ntawm 20x tam sim no. Yog tias Vs < Saturation V, nws dhau mus.
Cov txiaj ntsig: Chav kuaj- qib kev pov thawj kev nyab xeeb yam tsis muaj kev ntxhov siab tam sim no ntawm lub kaw lus.