高电压设备测试（High Voltage Equipment Testing）（英文版） 课件 Worksheet 1 Insulation Resistance Test.pptx

《HighVoltageEquipmentTesting》InsulationResistanceTest主讲人：何发武（副教授）

OperatingWorksheet：

OperatingWorksheet：

TableofContents01Followme02Workshop03Training

01Followme

Ⅰ.OverviewofinsulationresistanceMeasuringtheinsulationresistance,particularlytheabsorptionratioandpolarizationindexofthetransformer,ishighlysensitiveinassessingtheoverallinsulationcondition.Thismethodeffectivelyidentifiesissueslikemoisture,surfacecontamination,andthrough-holedefectsinthetransformerinsulation.Itcanalsodetectproblemssuchasshortcircuits,grounding,orcracksintheporcelaininsulation.Insulatingmaterialswithinthetransformer,includingtheinternalironcore,clamps,andthrough-bolts,playacrucialroleinensuringinsulation.Theinsulationinthewindingsectionscanwithstandhighvoltagelevels.

Ⅰ.OverviewofinsulationresistanceWhentheinsulationofthetransformeriscompromisedduetopiercing,damagetotheceramicinsulation,connectionoftheleadwiretothecasing,ortheoccurrenceofmetalshort-circuitfaults,therewillbeanoticeablechangeintheinsulationresistance.Moreover,thechangeininsulationresistancebeforeandafterequipmentdryingissignificantlylargerthanthechangeinthedissipationfactorofthedielectric.

Ⅰ.OverviewofinsulationresistanceForinstance,inthe7,500?kVAtransformer,thedissipationfactormaychangeby2.5timesbeforeandafterdrying,whiletheinsulationresistancemaychangebymorethan40times.Thischangeisquiteremarkable.Therefore,evaluatingtheinsulationresistanceofcomponentsliketheironcorecaneffectivelydetectoverallmoistureinthetransformerinsulation,surfacecontaminationofcomponents,andconcentratedthrough-holedefects.

Ⅰ.OverviewofinsulationresistanceTheabsorptionratioKreferstotheratiooftheinsulationresistancevalueat60secondstotheinsulationresistancevalueat15seconds.ThepolarizationindexPI