Constant speed operation is applied for the condensate pump. After being boostered by the condensate pump, the condensation water flows through the shaft heater and the main condensate water control valve (namely the water control valve on the deaerator) and the low-pressure heater, and then enters the dearator. The control valve opening of main condensate water is adjusted to control the condensate water amount and maintain the water level of the dearator and to stabilize requirement of unit. In addition, the condensate water is supplied for the attemperation water of low-pressure shaft seal steam of the steam turbine and for the attemperation water of low-pressure bypass and the attemperation water for water spraying of low-pressure cylinder of steam turbine. In order to prevent overpressure of condensate water and the caviation of the condensate pump cavitation during low-load operation of the unit, the recirculation piping of condensate water is designed. 

The basic methods for revamping are two-driven-by-one automatically /frequency conversion switching scheme.

Namely: one high-voltage converter, with two switches for changing-over. Through the switch, the high- voltage frequency converter is switched to the condensate pump to be operated. The power supply of the frequency converter is from the main power supply system of 6 kV voltage class, it is coordinated and controlled by the main control system of the site. According to the working condition and as per the set procedures, the rotating speed of the motor of the condensate pump is controlled. 

The high-voltage frequency -converter can drive the motor of Condensate pump A to realize  variable frequency operation, and through change-over, it can drive the motor of Condensate pump B to realize variable frequency operation, but it cannot drive the two motor at the same time. The motors at both sides of the condensate pump have function of power frequency bypass,  which can realize the variable frequency operation of any electric motor and power frequency standby of the other. When the high voltage frequency converter is in failure, the system can interlock the other power frequency motor to operate.