Medium voltage (MV) cables yog cov khoom tseem ceeb hauv cov tshuab hluav taws xob hluav taws xob, lub luag haujlwm rau kev nyab xeeb thiab siv hluav taws xob sib kis ntawm cov chaw nres tsheb, cov khoom siv hluav taws xob, thiab cov khoom xa tawm. Txawm li cas los xij, lawv cov kev ua tau zoo thiab kev ntseeg siab tuaj yeem ua rau lub sijhawm tsis zoo vim muaj ntau yam, suav nrog kev laus, kev ntxhov siab, ib puag ncig, thiab kev tsim khoom tsis raug. Ib qho kev kuaj mob zoo tshaj plaws uas siv los ntsuas qhov kev tiv thaiv ntawm MV cables yog qhov kev kuaj ib nrab (PD). Kev kuaj PD tuaj yeem ua tau ob qho tib si "ntawm- kab" thaum lub sijhawm U0 Soak Test lossis thaum lub zog thauj khoom, lossis "tawm-kab" thaum lub sijhawm dhau qhov ntsuas hluav taws xob AC Hipot ntawm ntau zaus, feem ntau VLF thaum kuaj teb
Off-kab ib nrab tso tawm txoj kev sim
Kev ntsuas hluav taws xob dhau los txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau nrhiav PD- ua qhov tsis xws luag. Kev ntsuas thiab kev txhais ntawm ib feem ntawm cov teeb liab tawm hauv qab thiab siab dua qhov kev khiav hauj lwm voltages yog ua. Magnitude, qhov chaw, thiab inception & extinction voltages yog tag nrho cov cim tseem ceeb ntawm cable mob.
Siv qhov hluav taws xob siab rau de- lub zog thiab kev sib txuas ntawm cable mus txog qib ua ntej - txiav txim siab thaum soj ntsuam cov txiaj ntsig, kom tsis txhob sim lossis qhov hluav taws xob nce ntxiv yog tias tsim nyog, txhawm rau tiv thaiv tsis ua haujlwm yog tias muaj PD. Sau cov ntaub ntawv xeem rau kev txheeb xyuas tom qab. Nws yog kev sim offline uas tuaj yeem siv tau:
1. 50/60 Hz. AC, pa hipot lossis resonant
2. VLF AC @ 0.10 Hz. - 0.05 Hz.
3. Damped AC @ 20 Hz. -500 Hz.
PD off-Kev ntsuam xyuas kab mob feem ntau suav hais tias ua tau zoo thiab txhim khu kev qha hauv kev kuaj xyuas qhov tsis xws luag, lawv qhov chaw nyob, thiab ntsuas lawv qhov hnyav. Offline PD xeem muaj txiaj ntsig hauv online los ntawm kev muab cov kev tswj xyuas overvoltage txhawm rau txheeb xyuas qhov tsis xws luag uas pib PD ntawm qib siab tshaj nominal.