Simulation And Experimental Study On Magnetostrictive Noise Of Toroidal Core Current Transformer

Current transformer is one of the most common and basic measurement equipment in power system,and its reliability plays an important role in the safe and stable operation of power system.In a power supply bureau,LR-220 type ring core current transformers are widely used on the line side of 220 kV gas insulated switchgear.The noise of this type of current transformer during normal operation is very severe,which seriously deteriorates the working environment of the substation.This article takes this type of current transformer as the research object,and carries out simulation research and experimental research on the vibration and noise of this ring-shaped core current transformer.In this paper,based on the magnetic domain theory and the JA model,the effect of irreversible magnetization on magnetization is ignored,and the magnetization model of the ring core current transformer is established;on the basis of this magnetization model,the secondary domain transfer model is used to establish the magneto Telescopic model;based on the magnetostrictive stress obtained from the magnetostrictive model,a pressure acoustic frequency vibration noise model is established.The magnetization model,magnetostrictive model and vibration noise model were used to analyze the magnetic induction intensity distribution,magnetostrictive stress distribution and vibration noise sound pressure level distribution in the ring core current transformer.An experimental platform for vibration and noise of a ring-shaped core current transformer was built.The vibration noise of the ring-shaped core current transformer with the change of primary current was studied experimentally,and the influence of the coil winding mode of the ring-shaped core current transformer on vibration noise was determined.In contrast,in the process of increasing the primary current from 0 to 1200 A,the maximum relative error of the simulated value of the sound pressure level was 7.05%,which verified the feasibility of the noise analysis of the simulation model;the magnetostrictive vibration of the ring-shaped core current transformer was determined It is the main source of noise for the ring core current transformer.The parameters such as the Young’s modulus,Poisson’s ratio,saturation magnetostriction constant,saturation magnetization,and initial permeability of the core of the ring core current transformer were changed.The influence of different parameters on vibration and noise was simulated and analyzed.Medium vibration noise is the most sensitive to changes in saturation magnetostriction constant.The saturation magnetostriction constant is reduced by 10%and the vibration noise level is reduced by 2.5 dB.By changing the coil winding method and the number of turns,the influence of the number of coil turns on the vibration noise was analyzed;the study found that,on the basis of ensuring the basic operating characteristics,by appropriately reducing the number of partial winding turns,the vibration of the ring core current transformer can be made The noise is reduced by 13.4 dB.