基于变压器绕组电路-漏磁场多状态解析模型的早期故障保护

Transformer Winding Early Fault Protection Based on Circuit-magnetic Leakage Field Multi-state Analytical Model

针对变压器绕组变形、轻微匝间故障等早期故障现有的保护方案难以有效的保护,该文提出了一种以漏磁场为特征量的变压器早期故障诊断方法。根据三相三柱式变压器的结构特征建立漏磁场分布模型,结合变压器状态空间方程,建立起与物理变压器保持一致的电路–漏磁场多状态解析模型。利用物理实体与多状态解析模型之间漏磁特征的差异性,可以不受励磁涌流的影响,快速、灵敏的识别复杂工况时发生的轻微匝间短路和轴向绕组变形,并能够确定故障位置。

Aiming at the ineffective protection of the existing schemes for protecting transformers against the winding deformations,the slight inter-turn faults,and the other early faults,in this study,a new method for the early fault protection of the transformers is proposed based on the leakage magnetic field as the characteristic quantity.According to the structural characteristics of the three-phase three-limb transformers,the leakage magnetic field distribution model is established.Combined with the state space equation of the transformer,a circuit-magnetic leakage field multi-state analytical model that is consistent with the physical transformer is constructed.The difference of the magnetic leakage characteristics between the physical transformer and the electromagnetic-structural coupling model is used to quickly and accurately identify the slight inter-turn fault and the axial winding deformation in complex working conditions without the influence of the inrush current,and the fault location is able to be determined.