Auxiliary-machine power system for double-machine backheating

Abstract

The invention relates to the field of thermal power generation and particularly provides an auxiliary-machine power system for double-machine backheating. The auxiliary-machine power system for double-machine backheating comprises a small steam turbine, a synchronous automatic clutch, a water feeding pump, a gearbox A, an alternating-current excitation electric-driven power generator, a gearbox B, a permanent magnet speed governor and a synchronous magnetizing exciter; the above equipment is connected through couplers in sequence. The stator side of the alternating-current excitation electric-driven power generator is connected into a high-voltage-station power application system and is provided with a synchronizing device; an alternating-current excitation circuit is arranged between the alternating-current excitation electric-driven power generator and the synchronous magnetizing exciter, the alternating-current excitation circuit is provided with an adjustable resistor, and the synchronous magnetizing exciter is provided with a direct-current excitation system. The rotation speed of the water feeding pump is controlled through the excitation frequency of a motor and is unrelated to the power of the motor, decoupling control over the rotation speed and the power is achieved, and difficulty of operation control is greatly lowered.

Description

technical field [0001] The invention relates to the field of thermal power generation, in particular to a small steam turbine-motor variable-speed dual-rotation control system for speed-power decoupling control of an EC-BEST (EchelonCycle-Backpressure Extraction Steam Turbine) dual-machine recuperation system of an ultra-(ultra)critical unit. The drive system is also suitable for the unit of the traditional heat recovery system, especially for the drive of the boiler feed water pump, and also suitable for the drive of variable speed drives and variable working conditions such as centrifugal fans and axial flow fans with adjustable vanes. It can improve the efficiency of the unit and the load response rate of the dual-machine regenerative unit. Background technique [0002] Due to the increasing requirements for energy saving and emission reduction, thermal power units are developing towards higher efficiency. Improving steam parameters is an important means to improve the po...

AI Technical Summary

Problems solved by technology

Thanks to the improvement of the flow design level of the BEST small machine, under the same conditions, the heat consumption of the thermal system using the BEST small machine is already lower than that of the traditional heat recovery system using the pure condensing small machine. The thermal system has attracted widespread attention, but since the steam extraction of the BEST small machine is connected to the high-pressure heater (referred to as "high-pressure heater") of the main steam turbine (referred to as the main engine), when the unit load changes or the feedwater flow fluctuates greatly under abnormal conditions, the high-pressure heater The water level is difficult to control, and there is no project put into operation to prove that the control problem of the BEST small machine has been solved

[0003] In addition, as the peak-to-valley difference of the power grid increases and a large number of new energy sources are connected to the power grid, thermal power plants are increasingly undertaking heavy peak-shaving and frequency-regulation tasks, resulting in more time for auxiliary equipment to deviate from the design operating conditions and fluctuate frequently. Reduction, especially the energy consumption level of large auxiliary machines such as feed water pumps and fans has a great impact on the efficiency of the unit, and new driving methods are also required to improve the driving efficiency of auxiliary machines

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