油浸自冷式变压器绕组热点温升的计算与分析

介绍了油浸自冷式变压器绕组热点温升计算的原理,对绕组热点系数的意义及取值范围进行了探讨,在此基础上对绕组热点温升进行了计算与分析。     

油浸变压器绕组加导油挡板结构时温升计算方法

介绍了饼式绕组加挡油板时铜—油温升(即绕组对油的温升)的计算方法，并与常规计算方法进行了比较分析。     

电力变压器绝缘材料寿命与热点温升限值的研究

通过给出GB/IEC以及IEEE标准中温升限值,对温升限值的环境条件进行了比较.通过研究绝缘纸的绝缘寿命,明确热点温升限值的意义,分析了热点温升限值差异的原因,并对使用IEEE标准的产品的绝缘纸的选择给出建议.     

油浸式电力变压器的温升试验及计算方法

论述并探讨了油浸式电力变压器的温升试验方法和温升的计算及校正方法,认为短路法和回归分析法分别是温升试验与计算的有效方法。     

油浸式变压器绕组涡流损耗及温升分布研究

利用有限元方法,分析变压器绕组涡流损耗的分布,并基于变压器发热与冷却理论,确定变压器绕组温升分布工程计算方法。通过产品算例的热点温升测量与计算结果比较,检验计算方法的合理性,为油浸式变压器绕组温升分布的合理计算和预防局部过热问题,提供了简单有效的分析方法。     

油浸式电力变压器非额定条件下的温升试验研究

介绍了非额定条件下确定油浸式电力变压器稳态温升的方法,验证了与额定条件下温升结果之间的一致性,能保证可靠地确定稳态温升。     

一种油浸式电力变压器绕组温升工程计算方法

油浸式电力变压器的绕组温升直接影响变压器的负载能力,而变压器绕组温升实验效率低、费用高,因此对变压器绕组温升进行工程计算研究具有十分重要的意义。目前大部分变压器厂用的工程计算方法没有统一的标准,造成计算结果不统一,误差较大。鉴于此,本论文在建立变压器绕组模型、分析绕组内油流特性的基础上提出一种变压器绕组温升工程计算方法,从工程实际出发对采用冷却器作为冷却装置的变压器在强油导向冷却方式下进行绕组温升工程计算,计算结果与变压器厂测得结果作对比,结果表明:该方法误差较小,可以满足工程实际需要。     

影响油浸式电力变压器振动因素的研究

变压器振动信号在运行过程中会受到各种因素影响。论文采用理论结合实验的方法研究了振动传感器安装位置、铁芯和绕组压紧程度、负载功率因数、负载三相不平衡度、绝缘油粘度对油浸式电力变压器振动信号的影响。研究结果表明：顶部测试位置可较好反映振动信号特性,铁芯和绕组压紧程度与振动强度呈反比,三相不平衡度和振动强度呈正比,功率因数影响振动信号频谱复杂度,绝缘油粘度对振动信号影响较小。     

运行中的早期油浸式电力变压器冷却系统的节能技术改造

概述 众所周知．目前我国单位GDP值的资源消耗是发达国家的数倍甚至十数倍，而宝贵的资源总是有限的。为了国家可持续发展，必须在发展过程中尽可能的降低资源的消耗，建设节约型社会，建设节约型企业。     

Dynamic thermal model of kiosk oil immersed transformers based on the thermal buoyancy driven air flow

This paper presents a dynamic thermal model of an indoor transformer station – transformer, high voltage and low voltage compartments are placed in a kiosk with inlet and outlet ventilation openings. The well-known dynamic thermal model of an oil immersed power transformer is extended with thermal models of walls and ceiling of the kiosk and natural air ventilation through the ventilation holes. The influence of wind velocity and the direction to convective heat transfer on each of the outer surfaces is taken into account. The solar calculator is developed and applied to determine the sun irradiation on each of the kiosk surfaces, taking into account shadows on some of the walls. The natural ventilation is modeled using equilibrium of pressure produced due to thermal buoyancy and pressure drop on the air path. The model is validated by comparing calculation results with the results of measurements on the transformer kiosk, with different surfaces of ventilation inlet and outlet openings. The model can be used in design phase to optimize ventilation openings (jalousies). Another application of the model is the estimation of the maximum possible load in forecasted ambient conditions, possible being applied in scope of smart grid concept.     

Mineral insulating oil in transformers

Nearly all load bearing transformers in electric power delivery systems around the world are filled with liquid. The liquid functions both as an electrical insulation and as a heat transfer fluid. The liquid in almost all of these units is transformer oil, petroleum-based insulating oil refined specifically to meet the requirements of this application. Transformers in electric power distribution and transmission systems are expected to function reliably and efficiently and to do this for many years. The quality of the oil in a transformer plays an important role in performing this function, and the characteristics of transformer oil have been examined and reported on for decades. This article discusses some of these characteristics and the relationships between these characteristics and the production and in-service performance of mineral transformer oil. Transformer oil is used around the world, but the emphasis here is on practices in the United States     

基于改进经验公式的油浸式变压器热点温度计算

本文基于GB/T 1094.7-2008中推荐的变压器指数方程法瞬态热点温度计算经验公式,针对S13-M-100kVA/10kV油浸式变压器,对经验公式在负荷下降以及环境中有风速作用时变压器瞬态热点温度计算误差较大的情况提出了修正因子,并使用Levenberg-Marquardt (L-M)算法对变压器热特性参数和风速修正因子进行寻优,改进了经验公式瞬态热点温度计算方法。使用改进后的经验公式对S13-M-100kVA/10kV变压器的多阶段温升试验过程中的热点温度进行计算,计算结果与试验结果最大误差不超过5℃,验证了本文提出方法的有效性和可靠性。     

变压器温度数据传输通道研究

研究了油浸式变压器温度计故障的产生机理,对常见故障现象进行了描述,提出采用"独立通道"消除缺陷的方法.     

特大型变压器油泥清除和油处理的效果分析

简要介绍了一核电站用特大型主变的运行情况。详细地介绍了XDK新型高效吸附剂和XFJ型变压器油多功能油处理机对核电站主变压器进行油泥清除和吸附处理的情况,并介绍了油处理结果。然后对此特大型变压器的运行情况进行了跟踪分析,列出和比较了同运行条件的处理过的和未经处理的2种变压器的运行油温、气相色谱分析和油介质损耗数据。通过处理后的变压器运行情况和油质追踪分析,尤其是对变压器油产气速率的分析证明出油处理和油泥清除的效果良好,证实了这套清除大型变压器内部油泥和改善其运行状态参数的方法是有效的。     

500 kV变压器油质异常的处理

分析研究11台不同国家生产的500 kV变压器油质状况以及国产油与进口油混合问题,对今后500kV变压器油的补油和换油问题、可能发生的各种变化、设备隐患的分析以及500 kV变压器油的监督和管理,提供了分析数据。     

Prediction of top-oil temperature for transformers using neuralnetworks

Artificial neural networks represent a growing new technology as indicated by a wide range of proposed applications. At a substation, when the transformer's windings get too hot, either load has to be reduced as a short-term solution, or another transformer bay has to be installed as a long-term plan. To decide on whether to deploy either of these two strategies, one should be able to predict the transformer temperature accurately. This paper explores the possibility of using artificial neural networks for predicting the top-oil temperature of transformers. Static neural networks, temporal processing networks and recurrent networks are explored for predicting the top-oil temperature of transformers. The results using different networks are compared with the auto regression linear model     

Calculation of core hot-spot temperature in power and distribution transformers

Accurate calculation of the value of the core hot-spot temperature at the design stage is becoming very critical in order to ensure that hydrogen generation that can be caused by oil-film degradation at core hot-spot temperatures as low as 110-120/spl deg/C is limited. Presented are two calculation methods developed for this purpose. Results of the FEM calculation of the location and value of the hot spot temperature in cores of three-phase, three-limb cores of power and distribution transformers show excellent agreement with tested values on a number of transformers. Insight learned from this analysis was used to enhance a previously available empirical method. This simplified calculation method is appropriate for everyday use and, hence, is suitable for design calculations. This method was shown to have again very good accuracy in the range of 2/spl deg/C for most of the cases. The simplified calculation method was also shown to provide a much greater accuracy than the original empirical method.