基于等效模型的介质损耗数值算法.pdf

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1、第39卷第11期电力系统保护与控制Vl0l_39NO．112011年6月1日PowerSystemProtectionandControlJun．1．2011基于等效模型的介质损耗数值算法徐志钮，律方成(生物质发电成套设备国家工程实验室(华北电力大学)，河北保定071003)摘要：基于电阻和电容并联或串联等效电路模型提出了一种在非整周期情况下仍有较高精确度的介损数字化算法。测量电容型设备绝缘上的电压和泄漏电流信号后使用傅里叶算法或加窗插值傅里叶算法和修正理想采样频率法获得信号的谐波分量，分别根据阻容并联／串联

2、等效电路模型以及电压信号对电流信号进行拟合，并将拟合模型中的变量进行适当的转化后使模型由非线性最小二乘变为线性最小二乘，直接计算获得电阻、电容进而得到介损和拟合泄漏电流信号，从而简化了计算。对仿真信号和实测信号的处理结果表明：阻容并联和阻容串联模型均能较好拟合电流信号，前者精度稍高；根据等效模型算法拟合后的电阻、电容计算所得介损在不同信号频率下仍有较高精确度，且该方法可获得绝缘的等效电阻和电容。关键词：电气设备；电介质；介质损耗；等效电路模型；最小二乘；频率Dielectriclossdigitalalgor

3、ithmbasedonequivalentcircuitmodelxuZhi·niu，LtiFang-cheng(NationalEngineeringLaboratoryforBiomassPowerGenerationEquipment，NorthChinaElectricPowerUniversityBaoding071003，China)Abstract：AdielectriclOSSdigitalalgorithmbasedonparallelorseriesequivalentcircuitmod

4、elofresistanceandcapacitanceiSproposed，andthealgorithmstillhashighaccuracyinnon-integerperiodssampling．Inthepaper，thevoltageandleakagecurrentsignalofcapacitiveelectricalequipmentinsulationaremeasured，andthosesignalharmonicsareobtainedbytheFourieralgorithmor

5、thewindowingandinterpolationFourieralgorithmandmodifiedidealsamplingfrequencymethod．Theleakagecurrentsignalisfittedbytheparallel／seriesequivalentcircuitmodelandthevoltagesigna1．Inthemeantime，varianceofthemode1．iStransformedtomakethemodelrumfromanon．1inearle

6、astsquaremodelintoalinearleastsquaremodel，whichhaslesscalculationwork，thentheresistanceandcapacitanceofthecircuitmodeliScalculateddirectly．Afterthen，thedielectriclOSSandthefitedleakagecurrentsignalofthecapacitiveequipmentareobtained．Theabovealgorithmsareuse

7、dtoprocessthesimulatedandrealmeasuredsignals，andtheresultindicatesthattheleakagecurentsignalcanbefittedwellbyparallelorseriesequivalentcircuitmodel，andtheformerhashigherfitingaccuracy；thedielectriclosscalculatedbytheproposedalgorithmsisaccurateindifferentsi

8、gnalfrequencies，inthemeantimethealgorithmcangiveequivalentresistanceandcapacitance．Keywords：electricalequipment；dielectric；dielectriclOSS；equivalentcircuitmodel；leastsquare；frequency中图分类号：TM835．4文献标识码：