交流滤波电容器装置电晕的噪声评估

The Assessment of Corona Noise on the AC Filtering Capacitor Installation

交流滤波电容器装置的噪声是换流站中噪声来源的主要因素之一,其噪声主要来自电容器外壳的振动和均压环等结构的电晕放电,因此电晕噪声水平的计算对研究和合理评估整个电容器装置的噪声水平有着重要的意义。文章从美国BPA推荐的交流输电线路可听噪声预估公式出发,推导出有限长线声源与点声源的电晕噪声预测公式,并结合500 kV交流滤波电容器装置的结构尺寸,利用ANSYS仿真软件计算其电场分布,得到表面电场强度较大的均压环和电容器引线端在测量点处的噪声水平,以此作为电容器装置电晕噪声的评估依据。结果表明:当满足计算条件时,预测公式可以得到比较理想的计算结果,并且随着结构表面电场强度的减小或测量距离的增大,电晕噪声呈指数规律降低。

The noise of AC filter capacitor installation is one of main noise sources in converter station, which mainly comes from vibration of capacitors shell and the corona discharge of grading rings. Therefore, calculation of corona noise level has great significance to the study and for reasonable estimation of the noise level of the whole capacitor installation. In this article, the predictor formula of finite length line sound source and point source is deduced from the audible noise predicting formulas recommended by BPA for AC transmission lines. Depending on structural dimension of 500kV A. C filtering capacitor installation, the electric field is calculated by ANSYS to get the corona noise level on the surface of grading rings and the lead end of capacitors with maximal electrical field strength as assessment base of corona noise of capacitor installation. The results show that the predictor formula could get more ideal result, and the corona noise level reduces in the exponential function with the reduction of electric field in surface structure and the rise of measuring distance.