Experimental Modal Analysis On Ac-filter Capacitor In Hvdc Converter Station

Capacitor devices is the basic elements of reactive power compensation devicein the electrical power system, which was widely used in High Voltage DirectCurrent (HVDC) converter station. Along with the increase of capacitor number、single-machine capacity、and the invasion of high harmonic current and so on,making the noise of the capacitor has become an unavoidable issue.So, carrying outthe dynamic properties analysis for capacitor、control the noise and vibration ofcapacitor、 fulfill the dynamic design of capacitor have become an importantresearch field.The paper studied the vibration and noise generation mechanism of capacitor、analysised the noise and frequency characteristics of a single capacitor componentsas well as the whole capacitor components, did research on vibrational and noisyradiation characteristics of capacitor when fundamental voltage and some n-orderharmonic voltage composited. Measuring and analysing the noise and vibrationsignal of capacitor and reactor in Ultra-High Voltage Direct Current (HVDC)converter station, when the AC-filter fiels at loads condition, using coherentseparation technology to extract the single capacitor noise from the complexacoustic environment, found power frequency100Hz and it’s harmonic frequencyhave the largest noise, and it’s noisy radiation owns directivity, accordance withtheoretica analysis.In order to further expounding whether the main frequency noise was causedby the structural resonance, using the Experimental Modal Analysis(EMA) methodto study on the natural vibrational characteristics of capacitor. Using differentexcitation signals and modes to excite capacitor, and did mode parametersidentification from Frequency Response Function(FRF). The results show: thevibration of capacitor in100Hz and its harmonic frequency is an forced vibration;single-ended sine sweep excitation and white noise excitation have the mostaccurancy.Through researching on this paper, on the one hand, normalized the excitesignal and excit mode in the test, on the other hand, it can provides a reference fordesigning low vibration and noise of capacitor according to the model parameters.