面向电气传感的杂散电流入侵变压器物理传播与特征信息提取OA

The stray current generated in HVDC transmission system and rail transit traction system will invade the transformer and lead to the abnormal vibration and noise.Aiming to this problem,experts and scholars at home and abroad have carried out relevant research.However,the difference between the two stray currents,the evolution and propagation of multi-information and the extraction method of characteristic information have not been explored in depth.Therefore,the evolution and propagation of magnetic-solid-noise multi-information are investigated when the transformer is disturbed by stray current. Firstly,the morphological characteristics of the two stray currents are compared and analyzed with the measured data,and the characteristic factors(DC factor and mutation factor Δm)are used to characterize the volatility and persistence.Then,the multi-physical field propagation and feature information extraction method of stray current invading transformer is proposed.Three-phase transformers(1 kV·A,220 V,15 kV·A,400 V)with different voltage levels are taken as the research objects to extract the physical information.The virtual simulation model and dynamic simulation experiment platform are built to obtain the electromagnetic,vibration and noise of the components in different scenarios. Through simulation and experiment,the following conclusions can be drawn:(1)The winding is affected by stray current,and the variation of magnetic flux leakage and vibration acceleration is similar.During no-load operation,the winding current,magnetic flux leakage and vibration have the characteristics of half-cycle asymmetry.Under the same load mode,the vibration and noise are more significant with the increase of the DC factor,and the time domain waveform is more distorted with the increase of the mutation factor.Under full load operation,the vibration amplitude of c_3 mode is 20%higher than that of c_0 mode,and the noise is increased by 15%.Under the same conditions,the vibration noise anomaly at the end of the winding is more obvious than that in the middle.Compared with HVDC transmission,the mutability of stray current in rail transit traction system makes the multi-field information present more complex timing characteristics.(2)Stray current intrusion considering DC factor can easily lead to core excitation bias.The degree of excitation saturation is more serious with the increase of DC level.The vibration amplitude of the core in c_3 mode is 23%higher than that in c_0 mode.In the same mode,the core is more susceptible to stray current intrusion than the winding. Finally,the feature information domain is formed by combining the multi-mode magnetic-solid-noise interaction information.The mapping relationship between stray current and vibration noise is studied by using characteristic factors.The characteristic information under different loads has similar mapping relationship.Combined with the characteristic information and the disturbance of equipment,the multi-field characteristic information domain can be divided into three state intervals:safe operation interval,risk early warning interval and abnormal instability interval.When 0＜c＜1.5 and 0≤Δm＜3.0,the transformer is less disturbed by the characteristic factor and is in the safe operation range;when 0＜c＜1.5 and 3.0≤Δm＜5.0,the degree of c interference is small,and the degree of Δm interference is large.When 1.5≤c＜2.5 and 0≤Δm＜3.0,the degree of c interference is large,and the degree of Δm interference is small.Although the transformer can resist the influence of the stray current,the vibration accumulation effect and environmental noise pollution of the component cannot be ignored.At this time,the transformer is in the risk warning interval.When 1.5≤c＜2.5 and 3.0≤Δm＜5.0,the interference degree of the characteristic factor is large,and when c＞2.5 or Δm＞5.0,the vibration noise of the transformer is very serious and the insulation is burned out.The transformer is in the abnormal instability interval,and the alarm action should be taken in time and the relevant suppression measures should be taken.