【作者】 杨蓓；

【导师】 王秀春；

【作者基本信息】 河北工业大学 ， 热能工程， 2007， 硕士

【摘要】 油浸式变压器具有散热好、损耗低、容量大、价格低等特点。目前电网上运行的电力变压器大部分为油浸式变压器。其中80%以上的油浸式变压器采用自然油循环冷却方式。为了解决变压器的“噪音扰民”问题和“油流带电”问题，在大型变压器上也开始采用自然油循环冷却方式。采用自然油循环冷却方式的直接后果是铜油温差加大，变压器的热问题更加突出。电力变压器是电力系统中的重要设备，它对电力系统的运行稳定性有重要的影响，而且其容量越大，热问题越突出。本文建立了传热与流动数学模型，完成了大型自然油循环导向冷却方式变压器的油流分布和绕组非稳态温度场计算。为变压器的设计和监控提供可靠的参数依据，进而为改善变压器结构设计提供帮助。其中，把油流分布简化为一维管网流动，并采用牛顿——拉普森法对其进行求解。根据变压器的特点，温度场的控制方程采用二维圆柱坐标下的导热微分方程。本文对变压器顶层油温升的计算根据最新提出的油浸式电力变压器负载导则，考虑了稳态和暂态温升。采用了最新规定的油指数、绕阻指数等值，使计算更加准确。本文编写了计算大型自然油循环导向冷却方式变压器温度场和变压器的寿命及负载计算的综合软件。适用于大型自然油循环导向冷却结构的变压器。对于导向区间个数，每区中油道个数，线饼和油道的几何尺寸没有特别的限制，可任意变化。本计算方法是针对每一柱线圈进行计算的，对变压器具有几柱线圈没有要求。对给定的负载周期图，计算热点温度和相对老化值。正常周期负载和急救周期负载时，给定时间段和初始连续负载，可计算相应时间段的负载值。从一定意义上讲，本文的计算方法可以指导变压器的结构设计、提高变压器的热设计水平，这对变压器的可靠运行、提高变压器的使用寿命、改善变压器运行状况、减少事故的发生都有积极意义，从而带来显著的社会效益和经济效益。更多还原

【Abstract】 Oil immersed transformer is widely used in power transmission because of its good coolant,low wastage and price, large capacity. At present, in oil immersed transformers natural oilcirculation is used at about 80%. In order to solve the noise-disturbing-citizen problem andremove the static electricity in oil flow, natural oil circulation has been wildly used in largepower transformer. A direct result of adopting natural oil circulation is to increase the temperaturedifference between copper and oil. So the heat elimination becomes more serious.Power transformer is the important equipmen of the electric power system. It has the importantinfluence to the electrical powersystem.,and moreover its capacity bigger, the heat elimination is moreserious.This paper sets up the mathematic model of heat transfer and oil flow, and finishes thecalculation of oil flow distribution and temperature field of winding in large natural oilcirculation power transformer with oriented cooling structure. The work of this paper will offerreliable reference data which can guide the design and the operation of the transformer and helpimproving the transformer design. In this paper, oil flow is described as one-dimension flow, andcalculated with Newton-Raphson method. According to the characteristic of the powertransformer, the temperature field of winding can be described with a partial differential equationin a cylinder coordinate system.In this articl,the calculation of the top temperature rice is based on the latest Loading guidefor oil-immersed power transformers.It has considered the stable state and the non-state state temperature rice. It used the newest stipulation oil index and the winding index that caused thecomputation to be more accurate.This article has compiled comprehensive software that can calculate the temperature field ofwinding and the length of life of the power transformer. This program is suitable for natural oiloriented circulation transformer. This program is not restricted by the number of ducts andoriented areas in windings and the size of duct and winding. It is not restricted by the number ofwindings in transformer either.To load periodogram which assigns, the program can computation hot spot temperatureandrelative aged value. When normal cyclical load and first aid cycleload is given, with the slot andthe initial continuous loading,it may calculate the corresponding time compartment the load value.Says from the certain significance,the computational methodmay this article can instruct thetransformer the structural design, enhance thetransformer the thermal properties and thetransformer theservice life, improve transformer movement condition, reduc the accidentoccurrence, thus brings the remarkable socialefficiency and the economic efficiency.更多还原