基于振动与电抗信息的变压器绕组形变状态综合监测方法

Looseness and deformation faults will appear in transformer winding after multiple short-circuit current shocks, and it is difficult to diagnose by single monitoring method. This paper proposes a composite monitoring method for state of transformer winding deformation. A model of vibration and reactance information monitoring is established to diagnose looseness and deformation faults winding. Mathematical equations and calculation models of winding deformation with vibration and reactance are established. Meanwhile, the laws of vibration and reactance information in looseness and deformation state are researched. Aiming at a 500 kVA transformer prototype, experiment of short circuit current impact is carried out, three kinds of deformation windings, including coil folding in end position, axial stretching looseness and radial extend in middle position are developed. Multi-information monitoring system of winding deformation state is designed. Data testing and state monitoring experiments on normal winding, loose winding after multiple short-circuit current impact and deformation fault windings are carried out. The experimental results show that, the vibration information of loose winding is 0.859 3, and the reactance information change rate is 0.096%. The vibration information of deformation fault windings are 0.876, 0.917 and 0.849, and the reactance information change rates are 5.61%, 3.31% and 9.25%. The experimental results indicate that the monitoring results are in accordance with practical status of windings. The new state monitoring method proposed in this paper can monitor the looseness and severely deformation status of windings effectively, which provide a basis for application of multi-information monitoring and digital twin.