Variable Frequency Drives (VFDs) are commonly used to drive Electrical Submersible Pumps (ESP), Beam Pumps, and Progressive Cavity Pumps (PCP), which extract oil from the ground.
VFDs on Electrical Submersible, Beam, and Progressive Cavity Pumps are susceptible to voltage sags and reclosure operations (tripped circuit breakers). A short sag or interruption in voltage (less than a 1/10th of a second) is enough to cause an undervoltage trip on a VFD, resulting in minutes or hours of downtime and costly production losses. A typical oil field can see 50 or more voltage sags per year, with 25+% able to trip the drive. Remote applications using reclosure (automatically resetting circuit breakers) to clear temporary faults from lightning, animal, or tree contact, will see more full interruptions in power. During these reclosure operations, the drives will trip — typically resulting in complete field outages.
Bonitron Undervoltage Solutions, including DC Bus RideThru, protect by regulating the pump's drive's DC bus voltage during sags and outages so that the pump will operate without interruption. Case studies show an increase of pump availability from 95.5% to 99.2%, resulting a six-week payback (@ $50 barrel).
A major oil extractor developed an oil field in Venezuela, which included the expansion and reconditioning of their existing 24 kV distribution system to ensure reliable service for the new and existing wells. All of the ESPs and PCPs, and some of the Beam Pumps, are driven by VFDs. Disruption to the PCP drives from voltage sags or reclosure operations resulted in 8 – 16 hours of lost production each occurrence. About 255km of overhead lines results in high exposure to lightning events resulting in subsequent sags and interruptions that cause well-site drives to trip, severely impacting production goals.
A strategy was developed to combine Bonitron RideThru with a reclosure system so that most disturbances would have no effect on production. Bonitron Ultracapacitor RideThru System's energy storage capacity was coordinated with the reclosure settings to allow for single or multiple reclosure operations. The Drive RideThru provided 0.75 seconds (45 cycles) of interruption capability on 60hp PCP drives. (Bonitron offers systems protecting up to 1MW for up to 15 minutes.