Research On Harmonic Suppression And Reactive Power Compension Of Oil Drilling Rig Electrict Drive System

Oil drilling rig electric drive systems are used massively in oil drill picks. Meanwhile,oil drilling rig systems are used in desert,sea and land that public grid can't arrive.The power station subsystems are constituted of diesel generator sets and corresponding control systems,it provides power supply to oil drilling rig (small grid power supply system).Drilling equipments are driven by high-power AC/DC motors.According to drilling craft need,speed is adjusted and torque is controlled.Usually,the drilling craft need is satisfied by VFD AC or SCR DC speed control system.It is well knowns that power electronic devices(VFD AC or SCR DC speed control system) bring harmonic pollution to power system. Especially,harmonic pollution will more serious for diesel generator small grid system,and low power factor of SCR electric drive system also bring additional burden and influence quality of power supplying.So,it is very important to carry on harmonic suppression and improve power factor.This paper is doing research and practice in view of this question.The structure and working principle of oil drilling rig electric drive system are introduced.Meanwhile,the reason and harm of SCR and VFD electric drive system are analyzed mainly.Combining development present situation domestic and foreign,the program of harmonic suppression and power improving is advanced to oil drilling rig electric drive system,and applied to actual projects.Oil drilling rig electric drive system is a typical multiple harmonic sources system.Each harmonic source is analyzed and their harmonic is superimposited and calculated.So,the total effect of grid system is determined in this paper.For structure and character of SCR and VFD electric drive system,it advanced different solutions of harmonic suppression and reactive power compensation.Then,it obtains a conclusion that harmonic suppression and reactive power compensation are necessary for SCR system.But,it is only necessary to suppress harmonic for VFD system.Analyzing and calculating for harmonic of SCR and VFD electric drive system provides design basis to program solutions and system optimization of the two system's harmonic suppression.The APF(rated voltage is 690V) is selected which is suitable in diesel generator sets small grid power supply system.In system structure,it uses the way of a harmonic source allocating an APF to solve the problem of connect CT to PT.The practice proved that the system allocation is right and filtering effect is good.Meanwhile,the dynamic reactive power installment is designed,advancing reactive power compensation effectively.It confirmed that the reactive power is compensated effectively to SCR electric drive system in this paper.