Analysis and Solution of Hydrogen-Cooled Generator Hydrogen Purity Decline

In generators operation,the hydrogen purity is an important monitoring indictor. The change of thepurity affects unit safety operation directly. Hydrogen purity of one #10 generator unit dropquickly. Determining how to find the mainfactors is the main objective. Primarily, it was analyzed that the main reason of hydrogenpurity decrease was the air enter the sealingoil system. Though analyzing DCS history curve,as well as temperature detection test, channeling oil test, and checking thesystem pressure, finally there were two reasons, one isfill oil valve leakage fault, the two is the oil pressure difference of hydrogen side and airside in balance valve aretoo large, causing the oil channeling from air side to hydrogen side.