Research On Electric Power Based Pumping Dynamometer Test System

The ground diagram is an important parameter of the oil well and the oil-well pump, and it is often used to judge the failure of the oil pump. The traditional test method is to use the dynamometer or the load-sensor to test. When the dynamometer is used, the test frequency is low, and the failure of the oil pump can not be found in time. When the load sensor is used, the sensor is subjected to alternating load for a long time, so it is very sensitive to failures, and the service life is short, and the data drift is easy to occur with time. Oil field proposed to test the power of the power to achieve the indirect measurement of the hanging point diagram, hoping to solve the problem of using electric power to calculate the suspension point load.In this paper, an accurate model of the power system based on power parameters is established, and a series of testing instruments are used to experiment of data acquisition. The error rate of the program is less than 10%.First, analysis of motion and force of pumping unit obtained suspended moving parameters and the torque formula. Analysis of efficiency and loss influence factors of the motor, the belt, and the deceleration device obtained their efficiency law of the different transmitted torque. The computational model of suspended point load and displacement has been established based on the electrical parameters. Due to considering the impact of efficiency change, beam's swing angle, the motor's speed fluctuation, the computational model has higher accuracy.Secondly, the hardware of the test system has been designed,motor power?the motor speed and the dead point position had been tested in no-load and in different balance degree?different stroke?different well condition and other experimental conditions. Through the data processing, the frequency converter efficiency, Inertia torque, total transmission efficiency of motor to crank shaft and other data was obtained.Then, based on the measured parameters of combined with total transmission efficiency curves, multiple sets of indicator diagram were calculated, the calculated diagrams were compared with the measured indicator diagram and error rate was less than 10%. The influence factors of the indicator diagram calculation accuracy were analyzed.At last, the calculation software of the dynamometer card based on the electric power has been compiled, which can realize the function of data acquisition, data processing, calculation of the indicator diagram, balance degree test and guidance.