典型油纸绝缘结构频域介电特性非线性变化规律

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关键词：电力变压器；油纸绝缘；频域介电响应；非线性介电特性；临界频率/场强DOI：10.15938/j. jhust.2025.05.011中图分类号：TM855 文献标志码：A 文章编号：1007-2683（2025）06-0102-09

Abstract：Oil-paper insulation is the main insulationsystem foroilimmersedpowerequipment.Accurately evaluating itsaging statusisrucialforthepowergridoperationandmaintenancedeparmenttoforulatemaintenancestrategies.Toclarifytheinfluencof testingexcitationamplitudeandtestig temperatureontevariationlawofdielectriccharacteristicsofol-immersedpowerqipment， andtoimprovetheaccuracyof evaluationresultsbasedoncurvecharacteristics，wide-temperatureandwide-frequencydielectric responseexperimentswereconductedonoil-paperinsulationsystems（pressboard-oilgap-pressoard）withdifrentagingdegees undervarious excitationamplitudes.Thetestresultsshowthatasthetesttemperatureincreases，thecharacteristicfrequencyrageof non-linearchangesintelossfctorcureshiftstowardshighfrequencies.Forteoil-paperinsulationmodelintelaterstageofaging， duetothesyergisticectofionalternatingolltionprocessandpositivandngativeioncompositemotioninthetransfoeril gap，thelossfactorcurveexhibitsdiferentnonlinearchanges inthehighandlowfrequencyranges.Meanwhile，acalculationmethod forcriticalfieldstrengthandcriticalfrequencywasproposedbasedontheoscilltionmodel.Theinflunceofdiferenttesting temperaturesandagingonthecriticalfrequencyandcriticalfieldstrengthofoil-paperinsulationsystemswasrevealed.Theresearch resultsfthispaperprovidecertainteoreticalsupportforcoductingonsitedagnossandanalysisofisulationstatusofoled power equipment based on frequency domain dielectric response detection technology.

Keywords： power transformer；oil-paper insulation；frequencydomain dielectricresponse；nonlinear dielectriccharacteristics; critical frequency/field strength

0 引言

电力系统作为我国能源运输的重要载体，其关键电力装备的稳定运行至关重要，在高压电力系统中，变压器、互感器、套管等油浸式电力设备及组部件由于长期在复杂的环境中运行，其绝缘出现不同程度的老化及受潮现象[1-8]，严重威胁电力设备的运行安全，因此在电网部门的日常运维中对其绝缘状态进行准确评估至关重要。（剩余13467字）