变压器内部温升计算与运行方式优化

发布时间：2018-09-05 11:34

【摘要】：变压器绕组热点温度和顶层油温是衡量变压器热状态的关键参量,对其进行计算和预测对变压器的运行安全和绝缘寿命评估有着重要意义。本文就变压器内部温升计算、散热效能计算和计及绝缘寿命损失的运行方式优化展开了大量工作。本文分别针对传统油浸式电力变压器和一种专用于地下变电站的分体式冷却变压器的内部温升计算展开了研究。针对传统电力变压器的顶层油温计算,本文建立了两种模型:点预测模型和区间预测模型。首先,结合半物理模型和数据驱动模型的优点,建立了基于核极限学习机(kerne1 extreme 1earning machine,KELM)误差预测补偿的顶层油温点预测模型,该模型的精度高于单一的半物理模型和数据驱动模型。然后,建立了一种基于KELM和Bootstrap方法的变压器顶层油温区间预测模型,模型预测区间的上下限值可以分别作为变压器顶层油温的保守估计值和乐观估计值,其保守估计值更适用于指导变压器的运行。最后,对分体式冷却变压器内部温升计算展开了研究。分体式冷却变压器一般应用于地下变电站,变压器本体位于地下,散热器位于地上环境中。结构的差异导致传统变压器内部温升计算模型不再适用于该类型的变压器,基于对该类型变压器散热原理的分析和与传统变压器热路模型的对比,提出了油浸自冷分体式冷却变压器的热路计算模型,并通过分体式冷却变压器的出厂温升试验数据验证了所提模型的有效性。本文建立了基于反向求解热阻法的变压器散热效能计算方法,利用在线监测的顶层油温数据,采用粒子群(partic1e swarm optimization,PSO)算法反向求解顶层油温对环境的热阻,根据实际热阻与出厂热阻的比值以及实际热阻的变化趋势对变压器的散热能力进行评价,以便及时发现变压器散热效能的变化,为其散热系统的运维提供辅助信息。本文提出将降低变压器热寿命损失作为变压器经济运行的目标之一,结合传统的综合损耗最小目标,建立了多目标变压器运行方式优化模型。基于变压器双时段控制策略,利用PSO算法求解备用变压器最优投切时间。本文从降低热寿命损失的角度为变压器的经济运行提供了一种参考方法。
[Abstract]:The hot spot temperature of transformer winding and the top oil temperature are the key parameters to measure the thermal state of transformer. It is important to calculate and predict the operation safety and insulation life of transformer. In this paper, a great deal of work has been done on the calculation of internal temperature rise of transformers, the calculation of heat dissipation efficiency and the optimization of operation mode taking into account the loss of insulation life. In this paper, the internal temperature rise calculation of traditional oil-immersed power transformer and a split cooling transformer for underground substations are studied. Aiming at the calculation of the top oil temperature of the traditional power transformer, two models are established in this paper: point prediction model and interval prediction model. Firstly, combining the advantages of semi-physical model and data-driven model, a top-level oil-temperature point prediction model based on kerne1 extreme 1earning machine,KELM error prediction compensation is established. The accuracy of the model is higher than that of the single semi-physical model and data-driven model. Then, a prediction model of transformer top oil temperature interval based on KELM and Bootstrap method is established. The upper and lower limit values of the prediction interval can be used as conservative and optimistic estimates of the top layer oil temperature of transformer, respectively. The conservative estimate is more suitable for guiding the operation of transformer. Finally, the calculation of internal temperature rise of split cooling transformer is studied. Split cooling transformers are generally used in underground substations where the transformer body is underground and the radiator is in the ground environment. Because of the difference in structure, the traditional calculation model of internal temperature rise of transformer is no longer suitable for this type of transformer, based on the analysis of the heat dissipation principle of this type transformer and the comparison with the traditional transformer heat path model, The heat path calculation model of oil-immersed self-cooling split cooling transformer is presented. The validity of the proposed model is verified by the temperature rise test data of the split cooling transformer. In this paper, a method for calculating the heat dissipation efficiency of transformers based on reverse solution of thermal resistance is established. Using the on-line monitoring data of the top oil temperature, the particle swarm optimization (partic1e swarm optimization,PSO) algorithm is used to reverse solve the thermal resistance of the top layer oil temperature to the environment. According to the ratio of actual thermal resistance to outgoing thermal resistance and the change trend of actual thermal resistance, the heat dissipation capacity of transformer is evaluated in order to find out the change of heat dissipation efficiency of transformer in time and to provide auxiliary information for the operation and maintenance of heat dissipation system. In this paper, it is put forward that reducing transformer thermal life loss is one of the objectives of transformer economic operation. Combined with the traditional objective of minimum comprehensive loss, the optimization model of multi-objective transformer operation mode is established. Based on the dual period control strategy of transformer, PSO algorithm is used to solve the optimal switching time of standby transformer. This paper provides a reference method for the economic operation of transformers from the angle of reducing thermal life loss.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM41

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