基于CFD的瓦斯继电器流场理论研究

发布时间：2018-04-21 09:54

本文选题：瓦斯继电器 + CFD数值模拟　；参考：《昆明理工大学》2017年硕士论文

【摘要】：瓦斯继电器是由马克斯·布赫霍尔茨于1921年研制发明的。自从问世以来,它便成为液冷变压器和接地电抗器重要的保护和监控设备。其不但具有结构简单、动作快、灵敏度高等特点,且运行稳定、可靠性高、安装简单一直被用作变压器内部的主保护装置。但近年来由于瓦斯继电器误动作引起的电力事故频发,给电力系统安全运行以及供电可靠性造成了巨大的影响,因此开展对瓦斯继电器的流场理论研究,对电力系统的安全稳定运行来说具有重大意义。目前进口 BF型双浮球型瓦斯继电器和国产QJ-80型瓦斯继电器在电力企业中应用较为广泛,本文就以这两种型号的瓦斯继电器作为研究模型。在查阅了大量的相关文献和科研动态分析的基础上,独立开展瓦斯继电器的流场理论研究。首先运用三维CAD建模软件Pro/ENGINEER对两种型号的瓦斯继电器进行三维实体建。为了模拟结果更加精确,在建模时对瓦斯继电器内部构造进行了详尽的刻画,使计算模型的参数尽可能的还原实测参数。并采用ICEM软件来完成计算流体域的网格划分,实现CAD与CFD技术的融合。本次瓦斯继电器的计算流体域采用结合结构化和非结构化网格优势的混合网格划分技术。之后基于动网格理论对两种型号的瓦斯继电器工作的全过程进行了动态CFD数值模拟,并对各自计算结果进行分析研究。研究结果表明:两种型号的瓦斯继电器的差异主要体现在对水流冲击力矩的敏感程度上,国产QJ-80瓦斯继电器的反应相对保守,进口 BF型瓦斯继电器的反应更灵敏。同时针对可能导致重瓦斯误动作原因①反向油流冲击;②抗振性能不足;展开了深入地分析。分析结果表明两种可能误动作原因①反向油流冲击导致重瓦斯误动作的可能性很小;②对抗振性能不足提出了相应的改良方案,并检验了改良方案的有效性。最后提出将CFD计算机仿真技术运用到瓦斯继电器油流整定值的校验方面。模拟试验结果表明:该方法能简洁有效地对瓦斯继电器油流整定值进行校验,并能清晰的反应瓦斯继电器内部指定时刻的流速分布状况。有效的提高了瓦斯继电器油流整定值校验的效率和可靠性。
[Abstract]:The gas relay was invented by Max Buchholtz in 1921. Since its inception, it has become an important protection and monitoring equipment for liquid-cooled transformers and earthing reactors. It not only has the characteristics of simple structure, fast action and high sensitivity, but also has the advantages of stable operation and high reliability. The simple installation has been used as the main protection device inside the transformer all the time. But in recent years, due to the frequent power accidents caused by gas relay misoperation, it has a great impact on the safe operation of power system and the reliability of power supply. Therefore, the flow field theory of gas relay has been studied. It is of great significance to the safe and stable operation of power system. At present, the imported BF double floating ball gas relay and the domestic QJ-80 gas relay are widely used in the electric power enterprise. This paper takes these two types of gas relay as the research model. On the basis of consulting a lot of related literature and dynamic analysis of scientific research, the flow field theory of gas relay is studied independently. Firstly, three-dimensional CAD modeling software Pro/ENGINEER is used to build three-dimensional entity for two types of gas relays. In order to get more accurate simulation results, the internal structure of gas relay is described in detail when modeling, so that the parameters of the calculation model can be restored to the measured parameters as much as possible. The ICEM software is used to mesh the computational fluid domain and the integration of CAD and CFD technology is realized. The gas relay in the computational fluid domain adopts the hybrid mesh generation technology combining the advantages of structured and unstructured grids. Then, based on the dynamic grid theory, the dynamic CFD numerical simulation of the whole process of the two types of gas relay is carried out, and the respective calculation results are analyzed and studied. The results show that the difference between the two types of gas relays is mainly reflected in the sensitivity to the impact moment of water flow. The response of domestic QJ-80 gas relays is relatively conservative, and that of imported BF type gas relays is more sensitive. At the same time, in view of the possible cause of heavy gas misoperation, the anti-vibration ability of reverse oil flow impingement is insufficient, and the deep analysis is carried out. The results show that the two possible causes of misoperation are as follows: (1) the possibility of heavy gas misoperation caused by reverse oil flow impact is very small and the corresponding improvement scheme is put forward for the deficiency of anti-vibration ability, and the effectiveness of the improved scheme is tested. Finally, the application of CFD computer simulation technology to the calibration of oil flow setting of gas relay is put forward. The simulation results show that the method is simple and effective to calibrate the oil flow setting of gas relay and can clearly reflect the flow velocity distribution of the gas relay at the specified time. The efficiency and reliability of oil flow setting check of gas relay are improved effectively.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM58

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