Analysis on drop of hydrogen purity of generator cooled by water-hydrogen-hydrogen and its countermeasures

According to the problem of drop of hydrogen purity for No.1 generator unit in Jinggangshan Power Plant,the hydrogen characteristics and the structure of oil-seal bearing and oil-seal system were analyzed. It was found that there exist some problems and incipient faults in the oil-seal system of the generator. After adjustment and reformation and optimization, the dropping rate of the hydrogen purity was controlled, which is adjusted from 1.4% per day to 0.08% per day. The consumption of hydrogen, which results from the purity of hydrogen drops, decreases from 70 m3 per day to 5 m3 per day and is within the better range. Considering the characteristics of structure of sealing bearing of 300 MW generator imported in technology and made in China, the proceedings that should be paid attention to in the operation and maintenance of the hydrogen system are presented. The description of the characteristics of hydrogen and the analyzing process and conclusion of the drop of the hydrogen purity can provide consultation for safe operation of the hydrogen system of the other same type of 300 MW generator cooled by water-hydrogen-hydrogen.