Research On Cascade Speed Regulation Technology Of Positive Pressure Feed Water Booster Pump In Mine

The drainage system of underground coal mine is an important facility for safe production of coal.In the process of drainage,cavitation corrosion will cause the water pump efficiency to drop,the pipeline aging and scaling will cause the pipe resistance to increase,resulting in the pump deviating from the high efficiency working area,as well as the pump selection design and the mine ground height is not fully matched,resulting in the mine drainage system energy consumption,inefficiency.Underground drainage system often use a high head,large flow,high power of centrifugal pump,the pump should be equipped with high power asynchronous motor to drive,directly for high power motor frequency control of motor speed control,can cause low power factor of asynchronous motor,increasing the load of power grid and power distribution equipment,and use the frequency conversion device big power,high cost and adjust the response time is long.Therefore,this paper proposes a series of variable frequency speed control technology of the booster pump,which is a centrifugal pump with small head,large flow,small power and adjustable speed in series at the front end of the high power centrifugal pump.Through the frequency conversion speed control of the booster pump,the small pump can drive the big pump to keep the drainage system running in the high efficiency area under the normal water inrush condition.This study is of great significance and economic value for improving the efficiency of drainage system and ensuring the safety and reliability of drainage system.The main research contents of this paper are as follows:(1)The change rule of flow and head of centrifugal pump in series operation and the adjustment method of pump working point are analyzed.Base on the characteristic equation and similarity theory of centrifugal pump,the energy saving principle of variable frequency speed regulation of single pump and the energy saving principle of cascade speed regulation of booster pump are analyzed.(2)Set up the centrifugal pump cascade speed regulation experiment platform,carry out frequency conversion speed regulation experiment of two centrifugal pumps with the same model cascade positive pressure feed water booster pump,and use Matlab software to perform curve fitting,solve polynomial regression equation coefficients,andanalyze the curve change rule.The mathematical model of cascade speed regulation system of two different types of centrifugal pumps with forward pressure feed water pump was built,and the variation rule of flow-efficiency curve was simulated and analyzed,and the variation rule of flow curve was compared with the experimental curve.(3)According to the actual working condition of the drainage system of coal mine,the mathematical model of the booster pump variable frequency speed control system is constructed with the efficiency of cascade drainage system as the optimization target.By using Matlab/simulink module and fuzzy PID adaptive control algorithm,the dynamic and static characteristics of the control system are simulated and analyzed,and the optimal variable frequency speed control method of the booster pump is determined.(4)Set up the main drainage pump cascade positive pressure water supply test platform,carry out the main drainage pump ground performance test,and analyze its efficiency;Industrial experiments are carried out on the inverter speed regulation of downhole cascade positive pressure booster pump,and the energy consumption and economic benefit are analyzed through data collection.