基于COMSOL的变压器中超声波传播特性

摘要

This paper establishes a simulation model of the transformer and studies in case of partial discharge power supply fixed, the sound pressure propagation in space, sound pressure amplitude variation in the spread process, the influence of the position of the partial discharge on signal propagation characteristics and acoustic attenuation of propagation in the core windings and transformer oil. Simulation results show partial discharge occurs within 1ms after the explosion, and the spatial distribution of the sound pressure inside the transformer changes rapidly, but there is no significant changes after 1ms. The change of sound pressure in the core and winding of the transformer is larger than that in the oil. Partial discharge explosion spreads to the surrounding medium in the form of wave front with spherical wave. The closer the position of the partial discharge power source is, the bigger of the received signal amplitude is. When acoustic wave propagates in the core, winding and transformer oil, the sound pressure amplitude possesses different attenuation in three directions due to the different propagation path and the increasing of the propagation distance. Experiments show the validity of the simulation results. And the analysis can provide the basis for the detection of partial discharge in transformer.%通过建立变压器仿真模型，分别研究了在局部放电源固定的情况下，声压在空间中的传播规律及其幅值变化情况、放电源位置对信号传播特性的影响及声波在铁心、绕组和变压器油中传播时的衰减规律。仿真结果表明，局部放电声爆炸发生后的1ms内，变压器内部声压的空间分布迅速发生变化，但是1ms之后无明显变化；变压器铁心和绕组中声压的变化幅度比油中更大，局部放电声爆炸以球面波形式的波阵面向周围介质传播；观察点离局部放电源位置越近，接受到的信号幅值越大；声波在铁心、绕组和变压器油中传播时，声压幅值在三个方向上因传播路径的差异随传播距离的增加经历不同的衰减。通过试验验证了仿真结果的正确性。该分析可以为变压器中超声波局部放电检测提供依据。