Reducing Electrical Submersible Pump Downtime by Mitigation of VSD Output Power Quality Problems

Abstract

Electrical submersible pumps (ESPs) are used in oil fields as an artificial lift method. Power quality problems of Variable Speed Drives (VSDs = Adjustable Speed Drives = Variable Frequency Drives) as related to ESPs pose risks in terms of the ESP short run-life and ESP failures which involve significant damage and down time. Not all VSDs are equal considering the implications of various topologies utilized in LV and MV VSD designs and the types of pulse width modulation (PWM) circuits commonly used in the oil field industry. VSD output issues that affect ESPs will be the primary focus of this paper and will be analyzed including current harmonics, ringing, pulsing torques, voltage transients, voltage stress, dv/dt, voltage reflections, and bearing currents (fluting). Present day solutions that extend runtime for ESPs based on input and output filtering will be described. New filter design techniques are presented utilizing developed computer models matched to actual measurements. In conclusion, several LV and MV ESP drive case studies using computer simulations and field measurements corroborate the new solutions.