【作者】 宋晓霞；

【导师】 王保保；

【作者基本信息】 西安电子科技大学 ， 计算机应用技术， 2010， 硕士

【摘要】 电力变压器是电力系统的重要电气设备,其运行状态直接影响着电力系统的安全性。因此,及早发现变压器潜伏性故障,是电力部门关注的一个重要问题。借助专家系统和模糊理论等技术可以有效地实现变压器故障诊断的智能化,促进变压器故障诊断技术研究成果的快速、有效转化。以油中溶解气体分析结果为特征量,利用三比值法对变压器进行故障诊断是一种十分广泛且有效的方法。本文在三比值法的基础上,利用人工智能相关技术构建了一个变压器故障综合诊断专家系统。该专家系统综合了基于产生式规则的诊断、模糊诊断和可视化诊断。当气体含量比值不在三比值法编码边界处时,采用基于产生式规则的方法进行快速诊断；当气体含量比值在编码边界处时,采用模糊诊断法以提高诊断准确率。进一步,为了使用户能更清晰、直观地观测到变压器当前运行故障在故障空间中的位置,该综合诊断专家系统同时给出了可视化立体图示法和杜威(Duval)三角形法。这两种方法降低了模糊诊断方法所需要的计算负载,且杜威(Duval)三角形法总能给出一种辅助诊断结果。实例证明,本文提出的变压器故障综合诊断专家系统,能够有效避免采用单一变压器故障诊断方法带来的诊断出错和得不出诊断结果等问题。并且,对于部分判断结果可以用该专家系统中的三种方法进行相互验证,从而提高诊断的准确性。更多还原

【Abstract】 Power transformer is important electrical equipment in the electrical system, and the running status of the transformer affects directly the safety of the electrical system. Therefore, it is vital for electrical department to find out the potential faults of the transformer as soon as possible. With aids of the expert system and the fuzzy theory, the intelligent transformer fault diagnosis is achievable. And the intelligent realization accelerates the engineering application of the research results of the transformer fault diagnosis.In general, the IEC-three ratio method is an effect method to be used in the transformer fault diagnosis based on the dissolved gases analysis (DGA) results. In this thesis, a novel transformer fault diagnosis method is presented by combining the IEC three-ratio method and the artificial intelligence techniques. The proposed method constructs a transformer fault integrated diagnosis expert system consisting of the IEC three-ratio method based on production rule, fuzzy diagnosis, and visual technique. In this expert system, the IEC three-ratio method based on production rule is used when the gas ratio is far from the three-ratio bounds, while the fuzzy diagnosis is utilized to increase the probability of correct diagnosis when the gas ratio lies in the three-ratio bounds. Furthermore, in this expert system, we present the visualized cubic schema method and visualized Duval triangular schema method to make the subscriber have a clean and intuitionistic view of the position of the transformer faults. In fact, the two visualized method can decrease the computational load of the fuzzy diagnosis, and the visualized Duval triangular schema method can always give an assistant diagnosis result.Simulation results are also given to validate the proposed integrated diagnosis expert system. In particular, the proposed integrated diagnosis expert system can decrease effectively the probability of wrong diagnosis and avoid the problem of having no diagnosis results. Further, we can use the three methods in the expert system to check some diagnosis results simultaneously, which will result in an increased probability of correct diagnosis.更多还原