Research And Development For Harmonic And Reactive Power Dynamic Tracing Compensation Technology Of Oil Well

Oil is one of the most important raw materials in the development of modern industrial society,which concerns the national economic development and social stability.At present,the beam pumping unit is the widely used oil production method in our country.The power factor of oilfield distribution network is very low because of it's load characteristics,which influence the economic operation level of the power grid.In addition,with the wide application of the nonlinear equipments to oilfield that the transducer represents,a great amount of harmonic currents are generated in power system,which bring all kinds of bad effects to the power grid and electric equipment.Therefore,study a harmonic and reactive power dynamic tracing compensation technology suitable for oil well power supply system is crucial.The various existing harmonic suppression and the reactive compensation are introduced,as well as their respective advantages and disadvantages.In the meantime the load characteristics of pumping unit are analyzed.It is hereby proposed that the hybrid compensation system combining active power filter(APF)and thyristor switched capacitor(TSC)shall be applied for oil well as to carry out the harmonic and reactive power dynamic tracking compensation towards the load of pumping unit.The proposed scheme shall meet the requirement of the special load like pumping unit calling up rapid response speed of compensation system,and accordingly the problems are resolved,including the difficulty to promote capacity of APF while exclusively applying it and the high cost.In view of the loading condition where the pumping unit is directly driven by transformer of oil well,the reactive power compensation is attached major importance.The majority of dynamic reactive power is mainly compensated by TSC through switching appropriate capacitor bank.Hereafter the TSC and pumping unit load are equivalent to the new load.The part besides the cardinal reactive power,varied with time dramatically,shall be compensated by APF as to promote the power factor.The harmonic suppression is given the priority in the load condition where the pumping unit is mainly driven by transducer.Therewith merely the APF is operated to reduce the total harmonic distortion of current.The topological structure of main circuit and the working principle of APF and TSC are analyzed.The harmonic and reactive power detection algorithm,the compensation current control algorithm and the voltage closed-loop control strategy of APF are discussed,and the selection principle of TSC's switch time is clarified.The control strategies of i_p-i_q method on the basis of instantaneous reactive power theory and of hysteresis current tracing are highlighted for research.Whether the strategies are feasible or not is certified through integrating the data measured practically and establishing the simulation model by adopting MATLAB/SIMULINK.The APF low pressure experimental platform is designed,with the control core of Yanxu TMS320F28335,and the specific hardware circuit and software implementation are designed and illustrated in details.The experimental verification and analysis are carried out for experimental platform,including the research of debugging the experimental platform,and steady state and transient characteristics test of compensation system.Ultimately,combined with the cooperative program of Shengli oilfield,the hybrid compensation device which installed in“Yi 11-59”oil well of Hekou oil production factory is tested.The test result illustrates the validity of the proposed scheme,which shows bright application outlook and future study value in harmonic suppression and reactive power compensation for oil well.