DocumentCode :
256549
Title :
Diagnostics of the transmission properties of the slip ring system in doubly fed induction generators
Author :
Hermann Houenouvo, A.T. ; Hofmann, W.
Author_Institution :
Elektrotech. Inst., Tech. Univ. Dresden, Dresden, Germany
fYear :
2014
fDate :
12-15 Oct. 2014
Firstpage :
1
Lastpage :
7
Abstract :
The slip ring apparatus in doubly fed induction generators is used to transfer the rotor current from the rotating to the static part of the generator. During the current transfer micro brush fires occur in the contact area when the minimum contact force FC is not maintained. This depends on the spring force applied to the brush top side, the sliding speed Vs of the slip ring, the electrical variables (e.g. amplitude of brush current, contact voltage) and environmental influences (e.g. air humidity, ambient temperature, dust). All these variables are measured in our slip ring apparatus. Consequently, this rises the contact temperature that affects the wear of the contact materials (graphite). Using the envelope analysis method, the electrical variables were examined in the frequency domain, where the first and the even harmonic were considered. Since the system is asymmetrical, the mean of the side bands amplitudes for each position is calculated. To evaluate the influence of v and FC, the quotient with the fundamental amplitude AC is formed and is defined as the sparking intensity. With this method, both parameters the sliding speed and the contact force must be approximately constant and the measurement time must be at least 30 seconds.
Keywords :
asynchronous generators; graphite; maintenance engineering; rotors; contact force; doubly fed induction generators; electrical variables; envelope analysis method; frequency domain; graphite; microbrush fires; rotor current; sliding speed; slip ring system; sparking intensity; spring force; transmission property; Brushes; Fires; Force; Graphite; Rotors; Surface contamination; Diagnostic; Graphite; brushes and slips rings; diagnostic; envelop analysis method; forces; micro fires; side band analysis;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Electrical Contacts (Holm), 2014 IEEE 60th Holm Conference on
Conference_Location :
New Orleans, LA
Type :
conf
DOI :
10.1109/HOLM.2014.7031019
Filename :
7031019
Link To Document :
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