| In order to minimize the operation economy of the power plant,the condensing pump used by the active 200 MW unit is transformed by frequency conversion in our factory.Precondition unit can in any load condition of the safe and stable operation when the condensate pump frequency conversion transformation,the first in the design of control logic for the first goa l should be to maintain the deaerator water level fluctuations in the reasonable range,we should fully consider the internal and external disturbance of negative charge on the unit operation caused by the unit.In the design process,the control logic after the frequency converter tripping is included to ensure that the switching between the devices can be realized when the frequency converter fails.In this paper,two kinds of speed governing modes of condensate pump and throttle regulation are compared,and the reasons for the energy saving effect of variable speed regulation of condensate pump are expounded.The control mode of the condensing pump a fter frequency conversion is optimized,and a simple analysis and comparison of the adjustment method of the control parameters after the transformation is made.According to the operation state of the unit,different deaerator water level control modes are selected by single impulse control and three impulse control at low load and high load respectively,so as to reduce the fluctuation of the water level in the deaerator and ensure the normal operation of the unit.The basic operation of frequency converter is analyzed briefly in this paper,and the operation mode of a two inverter is determined.The control logic of main circuit of condensate pump running is determined,and the safety and parameter requirements of main equipment are listed.Condensate pump frequency conversion transformation,the condensate pump frequency tripping experiment,the unit load is 50% of rated load,during the whole experiment with condensed water flow as the observation object,when the valve opening degree of condensate pump outlet is set to automatically adjust the water flow state,the condensed water pump leads to mutation.The control system of PID in the experiment when the output parameters of the production of the arrogant allowed value,thus causing the PID control system for the overshoot,resulting in deaerator water level fluctuations,a threat to the safe operation of the unit.Then the condensate pump valve force tracking time extended from 12 s to 25 s,after adjusting the output PID control system parameter changes,can satisfy the deaerator water level fluctuation limit,reduce the pump frequency control of condensation of condensate pump of deaerator water level,ensure the unit can be run in safe condition.After the variable frequency transformation of the conde nsate pump,the static test and dynamic test of the unit are carried out.The test results of the unit can reach the target parameters and are better than the parameters before the transformation.Have automatic adjustment ability of unit after the transformation,the deaerator water level control is more reasonable.It can satisfy the condition constraint of the water level fluctuation of the deaerator during the operation of the unit,and the safety and stability of the unit operation is increased.The condensing pump operation is stable after the condensing pump in our factory,and the unit has no accident.In general,the frequency conversion transformation of the condensate pump in our factory has been successful.The related technology and experience can be used as reference for the other factories to implement the conversion of large power equipment.Through the conversion of frequency conversion technology to the condensate pump in our factory,the power consumption and emission reduction of the plant are further reduced,and the power plant's competitiveness is increased.The safety and economy of the unit at low load are guaranteed. |
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