Research on Indicator Diagram Inversion Method of Beam Pumping Unit based on Power-To-Load Transfer Coefficient

The suspension point indicator diagram of the beam pumping unit is an essential basis for judging the operating conditions of the pumping unit. It is common to use electrical parameters to invert the suspension point indicator diagram. However, the current methods of using electrical parameters to invert the suspension point indicator diagram have the problems of low accuracy and poor practicability. Based on this, the method of inverting the indicator diagram based on the power-to-load transfer coefficient method is proposed in this paper. The transfer coefficient of power-to-load is calibrated by measured instantaneous output power of the motor and suspension point load. Then the Fourier series is used to fit the transfer coefficient. The load is calculated by measuring the instantaneous output power of the motor, suspension point displacement, and fitted transfer coefficient and the inverse indicator diagram is obtained. The average coincidence rate of the inversion indicator diagram is 98%. This method can significantly improve the inversion accuracy and simplify the process, providing a new way for the engineering application of electrical parameter inversion indicator diagrams.