Generalized frequency conversion system for steam turbine generator unit

Abstract

The present invention provides a generalized frequency conversion system for a steam turbine generator unit. The system comprises at least a steam turbine (T) with an adjustable rotating speed, a water feeding pump (BFP), a generator (G), a speed increasing gearbox (GB), a variable frequency bus (a, c) and an auxiliary machine connected thereto. With a change in load of the unit, parameters of steam entering the steam turbine (T) and an extracted steam amount are correspondingly adjusted (changed), so that the rotating speed of the steam turbine (T) changes correspondingly; and thus the rotating speed of the water feeding pump (BFP) is changed through the speed increasing gearbox (GB) on the one hand, and the frequency of an alternating current outputted by the generator (G) is changed on the other hand. Other types of frequency converters do not need to be additionally provided. The system is simple, reliable, low in cost, and high in efficiency.

1 . A generalized frequency conversion system for a steam turbine generator unit, comprising a steam turbine with an adjustable rotating speed, a water feeding pump, a generator, a speed increasing gearbox, a variable frequency bus and an auxiliary machine, characterized in that the steam turbine is connected with the water feeding pump through the speed increasing gearbox to drive the water feeding pump; the steam turbine is connected with the generator to drive the generator to generate power; and the generator is connected with a motor of the auxiliary machine through the variable frequency bus. 
     
     
         2 . The generalized frequency conversion system according to  claim 1 , characterized in that the generalized frequency conversion system further comprises an industrial frequency bus and an industrial frequency power supply; and the motor of the auxiliary machine is connected with the industrial frequency power supply through the industrial frequency bus. 
     
     
         3 . The generalized frequency conversion system according to  claim 1 , characterized in that the generalized frequency conversion system further comprises a clutch system provided between the steam turbine and the generator. 
     
     
         4 . The generalized frequency conversion system according to  claim 3 , characterized in that the clutch system can be a separate safety coupling, or a separate clutch or a combination of a safety coupling and a clutch. 
     
     
         5 . The generalized frequency conversion system according to  claim 1 , characterized in that the generalized frequency conversion system further comprises a voltage transformer; and the voltage transformer is provided at the rear of an output end of the generator and is connected with the motor of the auxiliary machine through the variable frequency bus. 
     
     
         6 . The generalized frequency conversion system according to  claim 1 , characterized in that the generalized frequency conversion system further comprises a switch and an industrial frequency bus; the motor of the auxiliary machine is connected with the variable frequency bus through the switch; and the motor of the auxiliary machine is connected with the industrial frequency bus through the switch. 
     
     
         7 . The generalized frequency conversion system according to  claim 1 , characterized in that the number of the auxiliary machines is at least one.