Nishi presented on November 16th, during the IX ENAM – National Meeting of Rotating Machines, promoted by Cigre Brasil, the technical report ENDWINDING VIBRATION OF TURBOGENERATOR 234.4 MVA. The case study was carried out in conjunction with PETROBRAS and HARA ENGENHARIA. The presentation was conducted by engineer Giovani Adriano from NISHI.<\/p>\n
Endwinding vibrations is a failure mode that is becoming recurrent in large turbogenerators, especially those manufactured since the last two decades. This problem is not unique to one manufacturer and affects most of them, and may be related to market competitiveness and the need to reduce manufacturing costs. One of the parts affected by these cost reductions are the endwinding, which have suffered modifications in the old and consolidated fastening systems that did not present such problems.<\/p>\n
Combining the problems in the design\/manufacturing with the generator’s operating conditions, this problem can lead to major failures\/losses, in the most severe cases, lead to short circuit of the winding and consequent need for rewinding of the stator. Besides the clear losses with the sending of the generator for maintenance, there is also the high loss in energy production due to the inability to operate the machine. Thus, the identification of problems related to vibration in the endwinding should be found as soon as possible.<\/p>\n
By performing inspections, associated with periodic tests on the endwinding, failures and the most serious scenario can be avoided and as will be demonstrated in this article, by performing the bump test and the correct interpretation of its results, it is possible to identify the regions with endwinding vibration problem and perform the appropriate and timely corrections.<\/p>\n
Watch the presentation below:<\/p>\n