Study and analysis of wind turbine gearbox lubrication failure and its mitigation process

Abstract

Windmill lubrication failure is a major challenge to produce economical wind energy. The wind energy generate by wind turbine with associated equipment such gearbox and its failure occurred during the operation of 2 years. NREL (National Renewable Energy Laboratory) statistical analysis confirmed that everyone windmill out of 15 found failure due to gearbox lubrication contamination and degradation. The lubricant used in wind turbine are mineral and synthetic lube oil of grade ISO VG 320, polyalphaolefins, esters oils, polyglycols lube oil etc. During the periodic analysis the gearbox lube oil found highly contaminated, moisture content and degraded due to the load change, temperature and other environmental factors. The owner or operator company decides to replace the lube oil on every two years which is associated with the cost of $12000 to $15000 USD. The hydratight team perform the experimental analysis by doing on-site lube oil purification and it’s found acceptable to reuse the purified oil by another two year. The operational lube oil has found particle count of ISO 22/20/17 - NAS 12 with moisture content 613 ppm and increase of 0.6 mg KOH/g acidity level (TAN). But after the successful lube oil purification, the results found that the 16/14/11 (NAS-6), with moisture content less than 100 PPM and 0.1 mg KOH/g acidity level (TAN). This research paper aims to provide windmill gearbox lube oil failure cause and effect with its purification process with windmill gearbox lube oil acceptable results.