Measurement Technology Study On Noise Of Power Capacitor Based On Sound Intensity Method

Converter station is a key part in HVDC(high voltage direct current) projects. As china’s growing demand for electricity, which makes HVDC transmission technology has made great progress, But at the same time it becomes more prominent to the converter station equipment noise problems. The noise of power capacitor is the main noise sources in High Voltage Direct Current substation. As these capacitor installations with large size and high voltage consist of a large quantity of capacitor units, it is very difficult to measure and reduce the noise of these capacitor installations with external measurement. In order to reduce the noise effectively, it is very important to measure the noise characteristic of power capacitor correctly. So Measurement technology study on Noise of Power Capacitor has became an important research direction.The generation mechanism of power capacitor noise is described in the paper.the electrostatic force between electrodes leads to the vibration of capacitor tank and then the noise is produced and radiates out. The relation between vibration and noise frequency characteristic, vibration and current has been analyzed in frequency and time domain.Due to radiated noise from the sources overlap each other which makes it difficult to measure the noise of power capacitor accurately.The noise of power capacitor was separated by Sound-vibration coherence separation technology in AC filter field and got vibration and noise frequency characteristic of capacitor.It provides an actual evidence for noise radiation properties of capacitor.Sound intensity measurement technology is the most widely used acoustic measurement technology now. In this paper, power capacitor is set to research object. Through the discrete point sound intensity measurement and scanning sound intensity measurement, noise characteristics of power capacitor are discussed in the Simulated actual work. And then compared with vibration velocity measurement. At last,the3-d sound intensity distribution and the sound intensity contour map of every surface are obtained. And on this basis, the noise radiation characteristics of power capacitor on every surface are confirmed,which provided an intuitive effective theoretical basis for capacitor noise control and structural development.