Study of electromagnetic compatibility of variable-frequency-regulated electric drive of the drilling rig and electricity source of comparable capacity

Abstract

The aim of this work is to study and analyze the mutual influence of the electricity source and the  main electric drive of the drilling rig with the stepped and frequency-based regulation of the angular velocity. The paper presents the results of research on mutual influence of electricity source and electricity consumers of the drilling rig in various modes of operation of the main actuator during geological prospecting hole-drilling. The studies were conducted using the method of mathematical modeling in software environment MATLAB/Simulink. Models were made for two power supply systems  – diesel generator and transformer, and for two electric drive systems – unregulated and variable frequency induction motor. These models allow investigation of electricity quality under different operating conditions of the drive. The studies have time and power line parameter dependences of unregulated and variable frequency induction motor when starting. Comparison of two curves showed that the use of frequency-controlled cage induction motor  in  average  reduces  motor  starting  current by  80 %  and  voltage  deviation by  60%.  Comparison  of  the maximum  values  of  active  and  full  power  at  start  of  unregulated  and  variable  frequency  induction  motor showed that the use of the frequency converter makes it possible to choose a diesel generator with the power by factor of 1.5 less than in the case of an unregulated drive. It makes better use of diesel power and thereby reduces fuel consumption at the borehole drilling. The research shows that the use of variable-frequency induction motor can improve the electromagnetic compatibility of electricity source and the main drive of the drilling rig at their synchronous functioning, and reduce energy costs.