Abstract: Abstract:The condenser vacuum degree of the unit No.1 in Huilai Power Plant of Guangdong Yudean Group decreased. The system was investigated and analyzed, and it was determined that the factors influencing on the condenser vacuum degree are the temperature of the vacuum pump working liquid, the opening of the adjust valve of backwater of feed pump mechanical sealing water, the leakage of the hole on the condenser wall, through which the oil discharge pipe of the bearing box passes, and so on. The relevant treatment measures were adopted, and the condenser vacuum degree returned to normal value. The safety and the economic efficiency of the unit operation were improved.

Key words: Keywords:condenser, vacuum degree, vacuum pump working liquid, backwater of feed pump sealing water, oil discharge pipe of bearing box