变压器温升及其对绝缘老化影响的研究
|
摘要
变压器是电力系统中最重要和最关键电气设备之一,其运行的安全可靠性直接关系到电力系统的安全与稳定,绝缘状态是变压器寿命决定性因素,而温度是影响绝缘状态的主要因素,尤其是变压器热点温度。因此研究变压器内部温升及其对绝缘老化的影响,对变压器的运行管理和寿命评估具有积极意义。论文研究了变压器内部温升计算方法,变压器实际使用寿命估算方法,以及热特征参数对温升和绝缘等值老化结果的影响。
基于热电类比原理,将变压器内部热传递过程转换成易于求解的热路模型,建立了变压器顶层油温热路模型和热点温度热路模型,推导了顶层油温度和热点温度的微分方程,并基于IEC60076-7推荐的指数方程解法,得到了一种变压器内部温度计算方法,计算结果能与实测值很好的吻合,尤其是在负荷增加阶段,与实测值基本一致。在顶层油温热路模型和热点温度热路模型的基础上,建立了简化的热点温度热路模型,推导了热点温度与环境温度和负载系数的直接关系表达式,计算结果基本与实测值吻合。
根据收集的变压器负荷和环境温度数据,形成典型负荷和典型环境温度。基于IEEE绝缘等值老化计算模型,建立了一种变压器实际使用寿命预测方法,该方法考虑了负荷和环境温度的变化,对变压器实际使用寿命进行50次计算,并利用威布尔分布对结果进行分析,得出最大概率的实际使用寿命值；考虑负荷逐年增长和气温升高的影响,预测了在这种条件下的变压器实际使用寿命。当平均负荷小于额定负荷,而且实时负荷超过额定负荷的次数很少时,实际使用寿命远大于设计使用寿命；但如果频繁超过额定负荷,虽然平均负荷小于额定负荷,负荷过冲会造成变压器温度急剧升高,加速变压器绝缘老化。
研究了用于变压器内部温升和绝缘等值老化时间计算的热特征参数的物理意义,分析了热特征参数取值对计算结果的影响。以热特征参数在推荐值±10%的波动范围为例,利用蒙特卡洛法分别对常规负荷和高负荷的运行情况进行数据分析,研究热特征参数选取推荐值对结果精确度的影响。在常规负荷下,采用推荐值能基本满足估算精度要求；但是在高负荷下,推荐值与实际值的误差将给最终的计算结果带来更大的误差,如果需要得到较精确的结果,需通过温升试验进一步确定热特征参数实际取值。
The transformer is one of the most important and the most key electrical equipments in power system, and the safe and reliable operation directly relates to the security and stability power system. The insulation condition is the decisive factor of transformer life, and the temperature is the key factor of insulation condition, especially the hot-spot temperature. Therefore, the research of transformer internal temperature and influence on the insulation aging is of positive significance for transformer operation management and life assessment. The calculation method of transformer internal temperature, the method of estimate the actual service life, and the influence of the thermal characteristic parameters to the results of the insulation equivalent aging are researched.
Based on the thermoelectricity analogy method, the heat transfer process of internal transformer is transformed into the thermal circuit model, which is easy to be solved. The thermal circuit models for the top oil temperature and hot-spot temperature are established, and the top oil temperature and hot-spot temperature expressions are deduced. Based on the exponential equations solution recommended in IEC60076-7, a calculating method for transformer internal temperature is proposed. The calculation results are close to measured values, especially during the step of load increasing, the results are nearly the same to measured values. On the basis of the thermal circuit models for top oil temperature and the hot-spot temperature, the simple thermal circuit model for the hot-spot temperature is established. The direct expression of the hot-spot temperature to environmental temperature and load coefficient is proposed, and the results are similar to measured values.
According to the collection of transformer load and environmental temperature data, typical load and typical environmental temperature are formed. Based on the IEEE insulation equivalent aging model, a transformer actual service life prediction method is proposed. The method considers the changes of load and environmental temperature, and 50 times calculations are preformed. Using Weibull distribution on the results, the actual service life maximum probability value is obtained. Considering the influence of load and temperatures expanding gradually, the actual use life is forecasted. When the average load is less than rated load and little overload, the actual service life is far longer than its design service life. If the overload is often happened, although the average load is less than rated load, load overshoot can cause transformer temperature sharp rise. The transformer insulation aging will accelerate, because of the transformer temperature rise overshoot due to overload.
The thermal characteristic parameters of the calculations of transformer internal temperature and insulation equivalent aging are elaborated. The influence of each thermal characteristic parameter in calculation results is analyzed. By varying these variables under various load conditions and by Monte-Carlo simulation with uniform distribution and normal distribution of these variables, their influence in calculation accuracy is obtained. The influence is small under normal load, and the accuracy can meet the estimation needs by using recommended value. But it is great under heavy load, and the thermal characteristic parameters have to be obtained accurately to improve the calculation accuracy.
基于热电类比原理,将变压器内部热传递过程转换成易于求解的热路模型,建立了变压器顶层油温热路模型和热点温度热路模型,推导了顶层油温度和热点温度的微分方程,并基于IEC60076-7推荐的指数方程解法,得到了一种变压器内部温度计算方法,计算结果能与实测值很好的吻合,尤其是在负荷增加阶段,与实测值基本一致。在顶层油温热路模型和热点温度热路模型的基础上,建立了简化的热点温度热路模型,推导了热点温度与环境温度和负载系数的直接关系表达式,计算结果基本与实测值吻合。
根据收集的变压器负荷和环境温度数据,形成典型负荷和典型环境温度。基于IEEE绝缘等值老化计算模型,建立了一种变压器实际使用寿命预测方法,该方法考虑了负荷和环境温度的变化,对变压器实际使用寿命进行50次计算,并利用威布尔分布对结果进行分析,得出最大概率的实际使用寿命值；考虑负荷逐年增长和气温升高的影响,预测了在这种条件下的变压器实际使用寿命。当平均负荷小于额定负荷,而且实时负荷超过额定负荷的次数很少时,实际使用寿命远大于设计使用寿命；但如果频繁超过额定负荷,虽然平均负荷小于额定负荷,负荷过冲会造成变压器温度急剧升高,加速变压器绝缘老化。
研究了用于变压器内部温升和绝缘等值老化时间计算的热特征参数的物理意义,分析了热特征参数取值对计算结果的影响。以热特征参数在推荐值±10%的波动范围为例,利用蒙特卡洛法分别对常规负荷和高负荷的运行情况进行数据分析,研究热特征参数选取推荐值对结果精确度的影响。在常规负荷下,采用推荐值能基本满足估算精度要求；但是在高负荷下,推荐值与实际值的误差将给最终的计算结果带来更大的误差,如果需要得到较精确的结果,需通过温升试验进一步确定热特征参数实际取值。
The transformer is one of the most important and the most key electrical equipments in power system, and the safe and reliable operation directly relates to the security and stability power system. The insulation condition is the decisive factor of transformer life, and the temperature is the key factor of insulation condition, especially the hot-spot temperature. Therefore, the research of transformer internal temperature and influence on the insulation aging is of positive significance for transformer operation management and life assessment. The calculation method of transformer internal temperature, the method of estimate the actual service life, and the influence of the thermal characteristic parameters to the results of the insulation equivalent aging are researched.
Based on the thermoelectricity analogy method, the heat transfer process of internal transformer is transformed into the thermal circuit model, which is easy to be solved. The thermal circuit models for the top oil temperature and hot-spot temperature are established, and the top oil temperature and hot-spot temperature expressions are deduced. Based on the exponential equations solution recommended in IEC60076-7, a calculating method for transformer internal temperature is proposed. The calculation results are close to measured values, especially during the step of load increasing, the results are nearly the same to measured values. On the basis of the thermal circuit models for top oil temperature and the hot-spot temperature, the simple thermal circuit model for the hot-spot temperature is established. The direct expression of the hot-spot temperature to environmental temperature and load coefficient is proposed, and the results are similar to measured values.
According to the collection of transformer load and environmental temperature data, typical load and typical environmental temperature are formed. Based on the IEEE insulation equivalent aging model, a transformer actual service life prediction method is proposed. The method considers the changes of load and environmental temperature, and 50 times calculations are preformed. Using Weibull distribution on the results, the actual service life maximum probability value is obtained. Considering the influence of load and temperatures expanding gradually, the actual use life is forecasted. When the average load is less than rated load and little overload, the actual service life is far longer than its design service life. If the overload is often happened, although the average load is less than rated load, load overshoot can cause transformer temperature sharp rise. The transformer insulation aging will accelerate, because of the transformer temperature rise overshoot due to overload.
The thermal characteristic parameters of the calculations of transformer internal temperature and insulation equivalent aging are elaborated. The influence of each thermal characteristic parameter in calculation results is analyzed. By varying these variables under various load conditions and by Monte-Carlo simulation with uniform distribution and normal distribution of these variables, their influence in calculation accuracy is obtained. The influence is small under normal load, and the accuracy can meet the estimation needs by using recommended value. But it is great under heavy load, and the thermal characteristic parameters have to be obtained accurately to improve the calculation accuracy.
引文
[1]王昌长,李福祺,高胜友.电力设备的在线监测与故障诊断[M].北京：清华大学出版社,2006.
[2]王梦云.2004年度110 kV及以上变压器事故统计分析[J].电力设备,2005,6(11)：31-37.
[3]王梦云.110 kV及以上变压器事故与缺陷统计分析[J].供用电,2007,24(1)：1-5.
[4]王梦云.110 kV及以上变压器事故统计与分析[J].供用电,2005,2(22)：8-12.
[5]周青山.俄罗斯110-500kV电力变压器运行故障和事故分析[J].电网技术,2003,27(4)：76-78.
[6]WOODCOCK D. Transformers Get New Lease on Life[J]. Electric Light and Power, 1997,75(5):23.
[7]路长柏.电力变压器绝缘技术[M].哈尔滨：哈尔滨工业大学出版社,1997.
[8]杨启平,薛五德,蓝之达.变压器绝缘老化的诊断与寿命评估[J].变压器,2004(2)：13-17.
[9]国家电网公司生产部110(66)kV-500kV油浸式变压器(电抗器)管理制度宣贯培训读本[M].北京：中国电力出版社,2005.
[10]牟长江.用光纤技术直接测量变压器绕组热点温度[J].变压器,1995(11)：2-5.
[11]邱凌.热电偶在变压器温升测量中的机理及应用[J].计量与测试技术,2006,33(4)：16-17.
[12]常炳国,刘君华,王世阁.智能变压器绕组热点温度监测仪[J].工业仪表与自动化装置,2000(4)：25-26.
[13]IEEE Guide for Loading Mineral-Oil-Immersed Transformers[S]. IEEE Std C57.91-1995.
[14]Loading Guide for Oil-immersed Power Transformers[S]. IEC 60076-7.
[15]周利军.牵引变压器温升与微水扩散特性的研究及其状态预测[D].西南交通大学,2007.
[16]PIERCE L W. Predicting Liquid Filled Transformer Loading Capability [J]. IEEE Transactions on Industry Applications,1994,30(1):170-178.
[17]PIERCE L W. An Investigation of the Thermal Performance of an Oil Filled Transformer Winding[J]. IEEE Transactions on Power Delivery,1992,7(3): 1347-1357.
[18]PIERCE L W. Predicting Liquid Filled Transformer Loading Capability [J]. IEEE Transactions on Industry Applications,1994,30(1):170-178.
[19]PIERCE L W. An Investigation of the Temperature Distribution in Cast-resin Transformer Windings [J]. IEEE Transactions on Power Delivery,1992,7(2):920-926.
[20]SWIFT G, MOLINSKI T S, LEHN W. A Fundamental Approach to Transformer Thermal Modeling—Part I:Theory and Equivalent Circuit[J]. IEEE Transactions on Power Delivery,2001,16(2):171-175.
[21]SWIFT G, MOLINSKI T S, BRAY R. A Fundamental Approach to Transformer Thermal Modeling—Part II:Field Verification[J]. IEEE Transactions on Power Delivery,2001,16(2):176-180.
[22]SWIFT G, ZOCHOLL S E, BAJPAI M, et al. Adaptive Transformer Thermal Overload Protection[J]. IEEE Transactions on Power Delivery,2001,16(4):516-521.
[23]SUSA D, LEHTONEN M. Dynamic Thermal Modelling of Power Transformers: Further Development-Part I[J]. IEEE Transactions on Power Delivery,2006,21(4): 1961-1970.
[24]SUSA D, LEHTONEN M. Dynamic Thermal Modelling of Power Transformers: Further Development-Part II[J]. IEEE Transactions on Power Delivery,2006,21(4): 1971-1980.
[25]SUSA D, LEHTONEN M, NORDMAN H. Dynamic Thermal Modelling of Distribution Transformers [J]. IEEE Transactions on Power Delivery,2005,20(4): 1919-1929.
[26]SUSA D, LEHTONEN M, NORDMAN H. Dynamic Thermal Modelling of Power Transformers[J]. IEEE Transactions on Power Delivery,2005,20(1):197-204.
[27]SUSA D, NORDMAN H. A Simple Model for Calculating Transformer Hot-Spot Temperature[J]. IEEE Transactions on Power Delivery,2009,24(3):1257-1265.
[28]SUSA D, PALOLA J, LEHTONEN M, et al. Temperature Rises in an OFAF Transformer at OFAN Cooling Mode in Service[J]. IEEE Transactions on Power Delivery,2003,18(4):1110-1117.
[29]NORDMAN H, HIRONNIEMI E, PESONEN A J. Determination of Hot-spot Temperature Rise at Rated Load and at Overload[C]. CIGRE Paris Session,1990:103.
[30]NORDMAN H, LAHTINEN M. Thermal Overload Tests on a 400-MVA Power Transformer With a Special 2.5-p.u. Short Time Loading Capability[J]. IEEE Transactions on Power Delivery,2003,18(1):107-112.
[31]NORDMAN H, RAFSBACK N, SUSA D. Temperature Responses to Step Changes in the Load Current of Power Transformers[J]. IEEE Transactions on Power Delivery, 2003,18(4):1110-1117.
[32]TANG W H, WU H Q, RICHARDSON Z J. A Simplified Transformer Thermal Model Based on Thermal-Electric Analogy[J]. IEEE Transactions on Power Delivery,2004, 19(3):1112-1119.
[33]TANG W H, WU H Q, RICHARDSON Z J. Equivalent Heat Circuit Based Power Transformer Thermal Model[J]. IEE Proceedings-Electric Power Applications,2002, 149(2):87-92.
[34]汤焱,刘成远,郝忠言,等.变压器绕组热点温升的计算与实验研究[J].变压器,2001,38(2)：1-5.
[35]陈伟根,李孟励,孙才新,等.变压器绕组热点温度热电类比计算模型仿真[J].重庆大学学报,2010,33(12)：8-13.
[36]陈伟根,赵涛,江淘莎,等.改进的变压器绕组热点温度估算方法[J].高压电器,2009,45(1)：53-56.
[37]江淘莎,李剑,陈伟根,等.油浸式变压器绕组热点温度计算的热路模型[J].高电压技术,2009,35(7)：1635-1640.
[38]JIANG T S, SUN C X, CHEN W G, et al. Comparison of Two Thermal Circuit Models for HST Calculation of Oil-immersed Transformers[C]. International Conference on Condition Monitoring and Diagnosis(CMD),2008:1008-1011.
[39]HE Q, SI J, TYLAVSKY D J. Prediction of Top-oil Temperature for Transformers Using Neural Networks [J]. IEEE Transactions on Power Delivery,2000,15(4): 1205-1211.
[40]RYDER S A. A Simple Method for Calculating Winding Temperature Gradient in Power Transformers[J]. IEEE Transactions on Power Delivery,2002,17(4):977-982.
[41]RYDER S A, HE Q, SI J, et al. Discussion of "Prediction of Top-oil Temperature for Transformers Using Neural Networks" and Closure [J]. IEEE Transactions on Power Delivery,2001,16(4):825-826.
[42]RYDER S A, VAUGHAN I J. A Simple Method for Calculating Core Temperature Rise in Power Trans formers [J]. IEEE Transactions on Power Delivery,2004,19(2): 637-642.
[43]廖瑞金,胡舰,杨丽君,等.变压器绝缘纸热老化降解微观机理的分子模拟研究[J].高电压技术,2009,35(7)：1565-1570.
[44]廖瑞金,周旋,杨丽君,等.变压器油纸绝缘热老化过程的中红外光谱特性[J].重庆大学学报,2011,34(2)：1-6.
[45]杨丽君,廖瑞金,孙会刚,等.变压器油纸绝缘热老化特性及特征量研究[J].电工技术学报,2009,24(8)：27-33.
[46]廖瑞金,邓小聘,杨丽君,等.油纸绝缘热老化特征参量的多元统计分析[J].高电压技术,2010,36(11)：2621-2628.
[47]LIAO R J, TANG C, YANG L J, et al. Thermal Aging Studies on Cellulose Insulation Paper of Power Transformer Using AFM[C].8th International Conference on Properties and applications of Dielectric Materials,2006:426-429.
[48]周利军,吴广宁.牵引负荷对变压器绝缘老化和寿命损失的影响[J].电力系统自动化,2005,29(18)：90-93.
[49]ZHOU L J, WU G N, YU J F, et al. Thermal Overshoot Analysis for Hot-spot Temperature Rise of Transformer [J]. IEEE Transactions on Dielectrics and Electrical Insulation,2007,14(5):1316-1322.
[50]周利军,吴广宁,汤浩,等.计算Scott牵引变压器内部温升的热路模型法[J].高电压技术,2007,33(3)：136-139.
[51]WU G N, ZHOU L J. Calculating Temperature Rise of Traction Transformer Using Thermal Circuit Model[C]. International Conference on Condition Monitoring and Diagnosis(CMD),2006:913-917.
[52]于钦学,谢恒,任文娥.用多参数研究变压器油的热老化[J].变压器,1998,35(12)：14-15.
[53]陈曦,于钦学,任文娥,等.变压器油的热分解动力学研究及其寿命预测[J].西安交通大学学报,2009,43(8)：112-115.
[54]任双赞,钟力生,于钦学,等.变压器油加速热老化过程中的多参量相关-回归分析[J].西安交通大学学报,2010,44(10)：88-92.
[55]徐树铨.电力变压器运行[M].北京：水利电力出版社,1990.
[56]邹建明,蔡汉生.500kV变压器的冷却方式[J].华中电力,2005,18(1)：31-32.
[57]王晓莺.变压器实用技术大全[M].北京：机械工业出版社,2004.
[58]陈书敏,石玉美.变压器及其冷却方式简介[J].变压器,2010,47(4)：50-53.
[59]电力变压器第2部分温升[S].GB 1094 2-1996.
[60]吴广宁.高电压技术[M].北京：机械工业出版社,2008.
[61]吴广宁.电气设备状态监测的理论与实践[M].北京：清华大学出版社,2005.
[62]刘鉴民.传热传质原理及其在电力科技中的应用分析[M].北京：中国电力出版社,2006.
[63]杨世铭,陶文铨.传热学[M].北京：高等教育出版社,2006.
[64]电力变压器第7部分油浸式电力变压器负载导则[S]. GB/T 1094.7-2008.
[65]保定天威保变电气股份有限公司.变压器试验技术[M].北京：机械工业出版社,2006.
[66]姜会飞,温德永,李楠,等.利用正弦分段法模拟气温日变化[J].气象与减灾研究,2010,33(3)：61-65.
[67]蒋仁言.威布尔模型族——特性、参数估计和应用[M].北京：科学出版社,1998.
[68]AUBIN J, LANGHAME Y. Effect of Oil Viscosity on Transformer Loading Capability at Low Ambient Temperatures [J]. IEEE Transactions on Power Delivery,1992,7(2): 516-522.
[69]PETERCHUCK D, PAHWA A. Sensitivity of Transformer's Hottest-Spot and Equivalent Aging to Selected Parameters [J]. IEEE Transactions on Power Delivery, 2002,17(4):996-1001.
[2]王梦云.2004年度110 kV及以上变压器事故统计分析[J].电力设备,2005,6(11)：31-37.
[3]王梦云.110 kV及以上变压器事故与缺陷统计分析[J].供用电,2007,24(1)：1-5.
[4]王梦云.110 kV及以上变压器事故统计与分析[J].供用电,2005,2(22)：8-12.
[5]周青山.俄罗斯110-500kV电力变压器运行故障和事故分析[J].电网技术,2003,27(4)：76-78.
[6]WOODCOCK D. Transformers Get New Lease on Life[J]. Electric Light and Power, 1997,75(5):23.
[7]路长柏.电力变压器绝缘技术[M].哈尔滨：哈尔滨工业大学出版社,1997.
[8]杨启平,薛五德,蓝之达.变压器绝缘老化的诊断与寿命评估[J].变压器,2004(2)：13-17.
[9]国家电网公司生产部110(66)kV-500kV油浸式变压器(电抗器)管理制度宣贯培训读本[M].北京：中国电力出版社,2005.
[10]牟长江.用光纤技术直接测量变压器绕组热点温度[J].变压器,1995(11)：2-5.
[11]邱凌.热电偶在变压器温升测量中的机理及应用[J].计量与测试技术,2006,33(4)：16-17.
[12]常炳国,刘君华,王世阁.智能变压器绕组热点温度监测仪[J].工业仪表与自动化装置,2000(4)：25-26.
[13]IEEE Guide for Loading Mineral-Oil-Immersed Transformers[S]. IEEE Std C57.91-1995.
[14]Loading Guide for Oil-immersed Power Transformers[S]. IEC 60076-7.
[15]周利军.牵引变压器温升与微水扩散特性的研究及其状态预测[D].西南交通大学,2007.
[16]PIERCE L W. Predicting Liquid Filled Transformer Loading Capability [J]. IEEE Transactions on Industry Applications,1994,30(1):170-178.
[17]PIERCE L W. An Investigation of the Thermal Performance of an Oil Filled Transformer Winding[J]. IEEE Transactions on Power Delivery,1992,7(3): 1347-1357.
[18]PIERCE L W. Predicting Liquid Filled Transformer Loading Capability [J]. IEEE Transactions on Industry Applications,1994,30(1):170-178.
[19]PIERCE L W. An Investigation of the Temperature Distribution in Cast-resin Transformer Windings [J]. IEEE Transactions on Power Delivery,1992,7(2):920-926.
[20]SWIFT G, MOLINSKI T S, LEHN W. A Fundamental Approach to Transformer Thermal Modeling—Part I:Theory and Equivalent Circuit[J]. IEEE Transactions on Power Delivery,2001,16(2):171-175.
[21]SWIFT G, MOLINSKI T S, BRAY R. A Fundamental Approach to Transformer Thermal Modeling—Part II:Field Verification[J]. IEEE Transactions on Power Delivery,2001,16(2):176-180.
[22]SWIFT G, ZOCHOLL S E, BAJPAI M, et al. Adaptive Transformer Thermal Overload Protection[J]. IEEE Transactions on Power Delivery,2001,16(4):516-521.
[23]SUSA D, LEHTONEN M. Dynamic Thermal Modelling of Power Transformers: Further Development-Part I[J]. IEEE Transactions on Power Delivery,2006,21(4): 1961-1970.
[24]SUSA D, LEHTONEN M. Dynamic Thermal Modelling of Power Transformers: Further Development-Part II[J]. IEEE Transactions on Power Delivery,2006,21(4): 1971-1980.
[25]SUSA D, LEHTONEN M, NORDMAN H. Dynamic Thermal Modelling of Distribution Transformers [J]. IEEE Transactions on Power Delivery,2005,20(4): 1919-1929.
[26]SUSA D, LEHTONEN M, NORDMAN H. Dynamic Thermal Modelling of Power Transformers[J]. IEEE Transactions on Power Delivery,2005,20(1):197-204.
[27]SUSA D, NORDMAN H. A Simple Model for Calculating Transformer Hot-Spot Temperature[J]. IEEE Transactions on Power Delivery,2009,24(3):1257-1265.
[28]SUSA D, PALOLA J, LEHTONEN M, et al. Temperature Rises in an OFAF Transformer at OFAN Cooling Mode in Service[J]. IEEE Transactions on Power Delivery,2003,18(4):1110-1117.
[29]NORDMAN H, HIRONNIEMI E, PESONEN A J. Determination of Hot-spot Temperature Rise at Rated Load and at Overload[C]. CIGRE Paris Session,1990:103.
[30]NORDMAN H, LAHTINEN M. Thermal Overload Tests on a 400-MVA Power Transformer With a Special 2.5-p.u. Short Time Loading Capability[J]. IEEE Transactions on Power Delivery,2003,18(1):107-112.
[31]NORDMAN H, RAFSBACK N, SUSA D. Temperature Responses to Step Changes in the Load Current of Power Transformers[J]. IEEE Transactions on Power Delivery, 2003,18(4):1110-1117.
[32]TANG W H, WU H Q, RICHARDSON Z J. A Simplified Transformer Thermal Model Based on Thermal-Electric Analogy[J]. IEEE Transactions on Power Delivery,2004, 19(3):1112-1119.
[33]TANG W H, WU H Q, RICHARDSON Z J. Equivalent Heat Circuit Based Power Transformer Thermal Model[J]. IEE Proceedings-Electric Power Applications,2002, 149(2):87-92.
[34]汤焱,刘成远,郝忠言,等.变压器绕组热点温升的计算与实验研究[J].变压器,2001,38(2)：1-5.
[35]陈伟根,李孟励,孙才新,等.变压器绕组热点温度热电类比计算模型仿真[J].重庆大学学报,2010,33(12)：8-13.
[36]陈伟根,赵涛,江淘莎,等.改进的变压器绕组热点温度估算方法[J].高压电器,2009,45(1)：53-56.
[37]江淘莎,李剑,陈伟根,等.油浸式变压器绕组热点温度计算的热路模型[J].高电压技术,2009,35(7)：1635-1640.
[38]JIANG T S, SUN C X, CHEN W G, et al. Comparison of Two Thermal Circuit Models for HST Calculation of Oil-immersed Transformers[C]. International Conference on Condition Monitoring and Diagnosis(CMD),2008:1008-1011.
[39]HE Q, SI J, TYLAVSKY D J. Prediction of Top-oil Temperature for Transformers Using Neural Networks [J]. IEEE Transactions on Power Delivery,2000,15(4): 1205-1211.
[40]RYDER S A. A Simple Method for Calculating Winding Temperature Gradient in Power Transformers[J]. IEEE Transactions on Power Delivery,2002,17(4):977-982.
[41]RYDER S A, HE Q, SI J, et al. Discussion of "Prediction of Top-oil Temperature for Transformers Using Neural Networks" and Closure [J]. IEEE Transactions on Power Delivery,2001,16(4):825-826.
[42]RYDER S A, VAUGHAN I J. A Simple Method for Calculating Core Temperature Rise in Power Trans formers [J]. IEEE Transactions on Power Delivery,2004,19(2): 637-642.
[43]廖瑞金,胡舰,杨丽君,等.变压器绝缘纸热老化降解微观机理的分子模拟研究[J].高电压技术,2009,35(7)：1565-1570.
[44]廖瑞金,周旋,杨丽君,等.变压器油纸绝缘热老化过程的中红外光谱特性[J].重庆大学学报,2011,34(2)：1-6.
[45]杨丽君,廖瑞金,孙会刚,等.变压器油纸绝缘热老化特性及特征量研究[J].电工技术学报,2009,24(8)：27-33.
[46]廖瑞金,邓小聘,杨丽君,等.油纸绝缘热老化特征参量的多元统计分析[J].高电压技术,2010,36(11)：2621-2628.
[47]LIAO R J, TANG C, YANG L J, et al. Thermal Aging Studies on Cellulose Insulation Paper of Power Transformer Using AFM[C].8th International Conference on Properties and applications of Dielectric Materials,2006:426-429.
[48]周利军,吴广宁.牵引负荷对变压器绝缘老化和寿命损失的影响[J].电力系统自动化,2005,29(18)：90-93.
[49]ZHOU L J, WU G N, YU J F, et al. Thermal Overshoot Analysis for Hot-spot Temperature Rise of Transformer [J]. IEEE Transactions on Dielectrics and Electrical Insulation,2007,14(5):1316-1322.
[50]周利军,吴广宁,汤浩,等.计算Scott牵引变压器内部温升的热路模型法[J].高电压技术,2007,33(3)：136-139.
[51]WU G N, ZHOU L J. Calculating Temperature Rise of Traction Transformer Using Thermal Circuit Model[C]. International Conference on Condition Monitoring and Diagnosis(CMD),2006:913-917.
[52]于钦学,谢恒,任文娥.用多参数研究变压器油的热老化[J].变压器,1998,35(12)：14-15.
[53]陈曦,于钦学,任文娥,等.变压器油的热分解动力学研究及其寿命预测[J].西安交通大学学报,2009,43(8)：112-115.
[54]任双赞,钟力生,于钦学,等.变压器油加速热老化过程中的多参量相关-回归分析[J].西安交通大学学报,2010,44(10)：88-92.
[55]徐树铨.电力变压器运行[M].北京：水利电力出版社,1990.
[56]邹建明,蔡汉生.500kV变压器的冷却方式[J].华中电力,2005,18(1)：31-32.
[57]王晓莺.变压器实用技术大全[M].北京：机械工业出版社,2004.
[58]陈书敏,石玉美.变压器及其冷却方式简介[J].变压器,2010,47(4)：50-53.
[59]电力变压器第2部分温升[S].GB 1094 2-1996.
[60]吴广宁.高电压技术[M].北京：机械工业出版社,2008.
[61]吴广宁.电气设备状态监测的理论与实践[M].北京：清华大学出版社,2005.
[62]刘鉴民.传热传质原理及其在电力科技中的应用分析[M].北京：中国电力出版社,2006.
[63]杨世铭,陶文铨.传热学[M].北京：高等教育出版社,2006.
[64]电力变压器第7部分油浸式电力变压器负载导则[S]. GB/T 1094.7-2008.
[65]保定天威保变电气股份有限公司.变压器试验技术[M].北京：机械工业出版社,2006.
[66]姜会飞,温德永,李楠,等.利用正弦分段法模拟气温日变化[J].气象与减灾研究,2010,33(3)：61-65.
[67]蒋仁言.威布尔模型族——特性、参数估计和应用[M].北京：科学出版社,1998.
[68]AUBIN J, LANGHAME Y. Effect of Oil Viscosity on Transformer Loading Capability at Low Ambient Temperatures [J]. IEEE Transactions on Power Delivery,1992,7(2): 516-522.
[69]PETERCHUCK D, PAHWA A. Sensitivity of Transformer's Hottest-Spot and Equivalent Aging to Selected Parameters [J]. IEEE Transactions on Power Delivery, 2002,17(4):996-1001.