Baotou Donghua Thermal Power Co., Ltd. is located in Baotou, Inner Mongolia, equipped with 2×300MW steam turbine generator units, with each unit equipped with three 50% rated-capacity electric feed pumps driven by hydraulic couplers. The feed pump units are installed with the booster pump driven coaxially at a constant speed by the feed pump motor. Three electric feed pumps are available, with two in service and one as backup.

After the test and acceptance of the unit 168, the boiler feed pump (1C) had been running normally at around 0.2mm/s until overhaul in 2009, since when vibration has been existing. With pass of time, vibration is also increased day by day. By March 2, 2012, the vibration of the equipment suddenly increased, exceeding the alarm limit. Analysis on spectra showed that 1X frequency suddenly increased to 11.27 mm/s, forcing the equipment operation to be stopped.

In August, 2012, our vibration experts Liu Songyan and Zhao Jinmin went to the Plant and conducted condition monitoring and analysis on the equipment. The spectrum plots showed equipment fault was caused by too-high vibration and damaged balance caused by the turbulence of media. They concluded that faults happened inside the rotor cartridge or the impeller flow path had defects. They spent 12 days inspecting the feed pump, 78 days earlier than the planned period. Assuming the profit was RMB 0.03/KWH, we thus helped the units generate benefits an extra of RMB 16.84 million.