油纸绝缘气隙放电发展能量熵特征研究

Energy Entropy Feature Research in Air-Gap Discharge Development Process of Oil-Immersed Paper Insulation

油纸绝缘是变压器绝缘系统的重要结构之一,气隙放电是油纸绝缘局部放电的主要形式;研究气隙放电及其发展过程的特征信息,对于及时了解绝缘劣化状态和发现潜伏性故障具有重要意义。通过模拟实际变压器运行环境,建立气隙放电模型,根据油纸绝缘不同劣化状态的变化对局部放电能量分布造成的突变影响,构建了以不同频带能量分布为基础的能量熵模型,提出将能量熵作为气隙放电发展的新特征量,每次能量熵的"阶跃"变化分别对应油纸绝缘不同劣化状态的转换,通过试验验证了其有效性,为探索新的特征参量揭示油纸绝缘气隙放电的发展特性提出了新的思路。

Oil-immersed paper insulation is one of the important structures in transformer insulation system, and air-gap discharge is the primary form of partial discharge（PD） in oil-immersed paper. Thus, it is of great significance to study the new features of PD development process for detecting degradation states of insulation and potential faults. This paper builds an air-gap model in a simulative transformer tank to collect PD signals based on constant voltage method. According to the energy distribution singularities of PD signals caused by the variations of different degradation states, an energy entropy model is built based on energy distributions in different frequency bands. The new PD parameter, i.e. energy entropy, is put forward to reflect PD development process. Then each step change of energy entropy corresponds to the transformation of different degradation states, which was validated effectively through experiments. It provides a new idea to study the development characteristics of oil-paper insulation air-gap discharge.