In conversations with operators, we’ve heard a large amount of failures related to ESP Power. For this article, we explore this topic further and give a preview of the June 8th discussion of ESP Improvement Technology.

ESP Power Delivery - Switchboard vs VFDs

ESP power can be delivered in two main ways, through a switchboard or through a Variable Frequency Drive (VFD). A few of the pros associated with using line power through a switchboard is that the power tends to be cleaner, leading to high reliability and longer runtime. The considerations of this setup is that the ESP system design must have tight fluid volume and pressure parameters, placing strict limits on the pump. Innovations in electronics and semiconductors led to the invention of VFDs. VFDs are a device used to control the speed and torque of an AC motor by adjusting the motor’s input frequency and voltage. The pros of utilizing this system is that the operator can now change the speed of the motor to match operating requirements, but the tradeoff is that there is more heat output from the motors, and harmonic resonance can become an issue.

Power Quality in VFDs

Power Quality is the grid’s ability to supply a clean and stable power flow, which incorporates a pure sinusoidal wave form within a specified voltage and frequency. Due to the high amount of nonlinear loads, which is a situation where the current isn’t proportional to the voltage and it fluctuates based on the alternating load impedance, issues have come up with line side harmonics, which deal with the power being fed back into the grid, and load side harmonics, which affects ESP performance usually causing premature failure.

Some of these issues are pictured below and include voltage transients, sags, swells, and voltage waveform distortion including harmonics.

Figure 1: Power Quality

Source: Fluke - Power Quality Symptoms and Causes

In the Permian, the high activity has seen this issue of harmonic distortion so much that they implemented a regulation in 2014 putting a limit on the amount of harmonic distortion allowed, tackling the line side harmonics issues referenced above (Source: https://standards.ieee.org/ieee/519/3710/). This regulation, however, only tackles one side of the harmonics issue which is the line side that deals directly with the utilities ability to provide clean power. The image below, provided by ZDDQ, demonstrates this difference.

Figure 2: Line Side vs Load Side Harmonics Source: ZDDQ Electric - Line Side Harmonics and Load Side Harmonics

“Harmonics are a concern because they can cause excessive heating and pulsating and reduced torque in motors and generators; increased heating and voltage stress in capacitors; and misoperation in electronics, switchgear and relaying. In short, harmonics can lead to reduced equipment life if a system is designed without consideration for harmonics and if equipment is not properly rated and applied.” (Source: https://www.eaton.com/content/dam/eaton/products/backup-power-ups-surge-it-power-distribution/power-conditioners/harmonic-correction-unit/IEEE-std-519-1992-harmonic-limits.pdf)

When looking at load side harmonic distortion affecting ESPs, issues can surface in premature failures that show up as downhole cable short circuits, MLE and potheads, splices, wellhead feedthroughs, and more, but also in not meeting utility specifications. (source: https://doi.org/10.1016/j.aej.2017.03.050) Due to this, several technological innovations have been commercialized in the last few years that address certain parts of this power quality problem.

Interesting Innovators in this Space

Magney Grande’s Common Mode Filter

Nowadays most VFD providers will have sine wave filters as part of their system, but what these systems neglect to account for is common mode current and high frequency harmonics which is what Magney Grande offers through their patented Common Mode Filter (CMF) technology, which was commercialized in 2017. This technology can be used as an add on to your ESP/VFD system and has seen much success in reducing electrical failures but also some mechanical problems such as shaft breaks.

Mirus International’s Inversine™ Mirus is a company who specializes in dealing with industrial power quality and developed a sinewave filter called the Inversine™ that is meant to replace existing sinewave filters as it shows a higher efficiency and ability to tackle the differential mode current. Similar to the magney grande solution, they are able to improve electrical reliability in VFD operations and offer other types of harmonic filters.

• https://www.mirusinternational.com/inversine.php

ChampionX’s SMARTEN™ PurePower Pro

The SMARTEN™ PurePower Pro technology focuses on the output side of harmonic behavior, which deals with being able to prove that the power quality meets utility standards. This technology is earlier in commercialization as it launched in Summer of 2021.

• https://www.championx.com/resource-library/championx-introduces-harmonic-mitigation-solution-for-unconventional-wells/ https://www.championx.com/products-and-solutions/artificial-lift-technologies/electrical-submersible-pumping-systems/smarten-purepower-pro-harmonic-halter/

This article is just scratching the surface on this important issue of industrial power quality and harmonics mitigation. Let me know your thoughts/questions in the comments below and if there are other solutions who you’ve been impressed by!