Research On Key Technologies Of Power Capacitor Noise Control

With the continuous development of power industry in our country, especially the rapid development of high pressure and ultra-high DC power transmission project, electric power capacitor as a filter and reactive power compensation device is widely used in HVDC converter station.The capacitor devices usually consists of multiple capacitor tower,each tower capacitor is made up of hundreds of sets of capacitor array, in which a single capacitor’s noise is about 60 db.Therefore, by the thousands and hundreds of capacitor the superposition of radiation noise is as high as 90 db.At present, for the capacitor device noise pollution problems in converter station mainly adopt the passive acoustic noise barrier method, administrative measure noise barrier not only cost is high and there is no noise from noise, so the single power capacitor noise control technology has important significance.This article’s main research content is as follows:1.To study the power capacitor based on the theory of the finite element simulation method of vibration and noise.First to analyze the structure of the power capacitor to get its vibration simulation of incentive conditions, and then in LMS. Virtual lab software to establish the finite element model of power capacitor,then make the capacitor structure vibration simulation, followed by the capacitor structure vibration simulation result and acoustic boundary element method(BEM) theory as the foundation to acoustic simulation of power capacitor.Finally the feasibility of the simulation method are verified through the experiment.2.To study the noise radiation of power capacitor under current incentive,which is conducive to estimate the radiated noise of single power capacitor accurately.First of all, analyzing the theory of noise radiation.Second, applying the vibration acoustic frequency response function method to design the power capacitor’s noise radiation testing and validation experiment under current incentive.Third, analysis the result of the test.3.To study a noise control method of power capacitor, which setting the absorber between power capacitor core and power capacitor shell.First of all, based on the mechanical impedance method to establish the simplified vibration model of capacitor structure vibration.Then based on the vibration and noise reduction’s relationship and the property of bellow to design the shock absorber and manufacture the power capacitor samples which installing the bellow absorber and test noise reduction effect of capacitor samples.The experimental results show that the bellow shock absorber has a good performance of noise reduction and consistent with the design expectations. Especially, the bottom direction of capacitor’s noise reduction is maximum which the corresponding test sites of capacitor’s bottom direction’s noise reduction is up to 9 db.