Vibration and Noise Characteristics of Air-Core Reactor Used in HVDC Converter Stations

Abstract

Air-core reactors used in filters are significant equipment in HVDC converter stations. They are among the most serious noise sources under the action of multi-frequency magnetic forces. The vibration and noise characteristics of air-core reactors are investigated in this paper, which is the basis for noise control of HVDC projects. Firstly, based on the characteristics of magnetic forces, the generation process of vibration is analyzed theoretically. Then, Experimental Modal Analysis (EMA) is conducted and the results indicate that multiple natural frequencies exist and their mode shapes contain distinct peaks and troughs. Vibration shapes are also measured under different excitation frequencies with dense measuring points over the winding surface. The measured vibration shapes are consistent with the corresponding mode shapes. Furthermore, the noise distribution characteristics are analyzed by Boundary Element Method (BEM). The simulation results show that the noise radiation has obvious directional effect, which are mainly dominated by the corresponding vibrations and mode shapes. Based on the results of this paper, some suggestions for noise reduction are given in the last.