Optimal Control Strategy And Energy Saving Method Analysis For Motors Of Beam Pump Unit

Energy saving in oil production has always been a challenging market segment for energy efficiency.Among many ways of extracting oil,beam pumping is one of the most common ones because of the easiness of its application and its mechanical properties.Since most of the oil fields in Kazakhstan are equipped with beam pumps,the studies in this research work aim to target the oil fields that use beam-pumping units for oil production.Because the electric motor is the main energy-consuming element of the beam-pumping unit,it is of great importance and practical significance to address the energy saving problem and target the beam-pumping unit induction motor performance.Since oil is a natural resource,the amount of fuel being extracted sometimes might not be controlled.This will cause the induction motor experience excessive pumping operation if the well capacity is low,or great losses if the capacity is large.This paper proposes the optimal control strategy for motors of beam-pumping units that will ensure the most promising energy saving method.The method is to use wye-delta transformation to ensure the system automatic switchover to the most optimal operating state.The main idea of the proposed method of wye-delta automatic transformation is to switch its operation from delta to wye or visa versa depending on how much load the system is experiencing.When the load is light,the motor with a very high rated power will experience the waste of energy.In order to avoid that,the wye-delta method analysis will help us determine both the optimal switching time as well as optimal power value when the system needs to change its operation.After introducing the basic structure and power characteristics of the beam-pumping unit,this paper studies the power loss of the induction motor used in the oil production.Moreover,the research paper also studies the influence of the different working conditions and the varying load on under different voltage.In this paper the theoretical derivation of the optimal power value equation and calculation of the optimal power value have been conducted.Theoretical results served to be a defining parameter of further analysis.The MATLAB simulation results have been analyzed based on the equations and the power relations presented in the paper.The derived optimal power value determined the time and the reference point when the motor should switch the operation.In addition to the analysis,the average power loss of each cases,both delta and wye,have also been conducted.The results and the simulations demonstrated predicted behavior of the system.Under varying load and varying voltage the simulations revealed a power curve for each case.The optimal power value served as the boundary between the switching states.The simulations results clearly show that when the system experiences the light load,it is best to adopt the wye-delta conversion method,as it will allow us achieve higher energy-saving effect up to 10%.Because nowadays the technology is developing rapidly,it is important to keep in mind that with oil production,the energy saving is as important as the fuel itself.The results obtained from this research work provide us with a clear insight into the energy-saving options in oil production.The proposed method of the wye-delta automatic conversion will allow a smarter and a more efficient way of producing and extracting oil without any unnecessary losses.Moreover,because beam-pumping unit systems are widely used across the world,the proposed method can be adopted in any of the oil producing countries.As the matter of fact,this research work can open new opportunities for future studies of the applications of wye-delta conversion method for extracting different types of liquids,not limiting only to oil.