Vibration Velocity Distribution Characteristic of AC Filter Capacitor in HVDC System

Summary

Vibration of AC filter capacitor generates loud noises in HVDC converter stations, which would reach 105dB. Although there were several studies about the vibration and noise of the capacitors, no quantitative data of vibration velocity was measured. The objective of this work was to measure vibration velocity distribution on AC filter capacitor surfaces and to investigate relationship of vibrations between different points. In single-frequency experiments, the capacitor was applied with 550Hz 65.2A current. And in multi-frequency experiments, 50Hz 50A and 550Hz 35.5A currents were on the capacitor at the same time. A portable digital vibrometer was conducted to measure the vibration velocity on every capacitor surface. In order to obtain velocity data simultaneously, voltage squared was used as a datum signal to calibrate the time offset. The velocity waveform on a specific point was steady sinusoidal. Velocities on different measure points on a capacitor surface were not synchronous, and had different phases. On the bottom surface, 100Hz vibration velocity phase varied less than 1100Hz with positions. On the broad side surface, 100Hz phase offsets were larger than 1100Hz. The velocity distribution presented as a wave shape. These phase offsets may be caused by asynchronous forces, which were generated between eddy currents on the steel surface and aluminium bands in the capacitor.

Additional informations

Authors

Soucek Jakub, Beltle Michael, Schühle Michael, Costa Edson Guedes, Melo Alves Helem Monyelle