Noise analysis of high voltage capacitors and dry-type air-core reactors

Marcin Hurkala

    Research output: ThesisDoctoral ThesisMonograph


    The goal for this work was to create new methods to study the noise production in some power system components, namely capacitors and reactors. In the case of the capacitors the work was started by trying to create a FEM model of the individual capacitor element as well as each of the capacitor sides. In the end individual element proved to be too complicated to be modeled, but the sides were modeled using the assumption that they're individual clamped plates. To find out how the individual element behaves one was subjected to direct current of various amplitudes and the compression was measured with a dial indicator at various points. The compression was deemed to be linearly dependent on the distance from the middle point of the surface of the element. In order to measure the response of the whole capacitor, a vibration measurement was used. Vibration transducer was used on each side to get the overall vibration response of each side when the capacitors were fed various inputs. The responses were measured in three different temperatures. The direct acoustic response was measured in the anechoic chamber. This yielded new information about the directivity of the noise produced by the capacitors at the different frequencies. The results of the vibration measurement could be also compared to the acoustic measurements. The comparison resulted in partially incoherent results. Final measurement related to the capacitors was one where the viscosity of the capacitor oil was measured. This allowed to partially explain the variations in the vibration response at the different temperatures. The noise measurement of the reactors is difficult due to the high magnetic field caused by them. Since the direct measurement wasn't an option, a plastic tube extender was used to move the sound further away from the reactor where it could be then measured with regular microphone. The tube extender was used in one field reactor measurement, in one controlled reactor measurement, and its response was measured in the anechoic chamber. As a result it was found that the tube extender can be used in this kind of measurements, and perhaps could be in the future to use in recognizing the faults of the reactors before they become severe.
    Translated title of the contributionSuurjännitekondensaattoreiden ja ilmasydämisten kelojen meluanalyysi
    Original languageEnglish
    QualificationDoctor's degree
    Awarding Institution
    • Aalto University
    • Lehtonen, Matti, Supervising Professor
    Print ISBNs978-952-60-5361-5
    Electronic ISBNs978-952-60-5362-2
    Publication statusPublished - 2013
    MoE publication typeG4 Doctoral dissertation (monograph)


    • noise
    • capacitor
    • reactor


    Dive into the research topics of 'Noise analysis of high voltage capacitors and dry-type air-core reactors'. Together they form a unique fingerprint.

    Cite this