29 Oct 2021

Est Reading time: 11 minutes

The powerful oil and gas industry continues to fuel global demand. At the same time, the industry itself is in a continuous battle to keep operational costs manageable. Refineries, in particular, are known to be heavy energy users. Pumps, motors, compressors and boilers are some of the operational loads that consume a significant amount of electricity.

A stable source of electricity supply is key to ensuring smooth day-to-day operations at a refinery. Not only does it keep the entire refinery process chain operational, but a stable power source also ensures the safety and efficiency of producing petroleum products.

The Problem

Most refineries source electricity from the local grid. The intention of doing so is to ensure a clean and stable supply to the entire facility. However, there’s no assurance that incoming power from the local grid offers the stability or quality that a refinery needs. 

Power quality is dependent on various factors, such as the isolation transformer, wiring size & length and harmonics. Occasionally, refineries are faced with power quality issues that could hamper day-to-day operation.

Voltage Fluctuation

An unstable voltage level from the local grid produces a trickle-down effect on all primary and secondary systems. Constant voltage fluctuation affects operations of high-power modules such as motors and pumps. This could lead to disruption in refinery operations, unplanned repair and in some cases, total failure of certain equipment.

Undervoltage / Overvoltage

Similar problems could occur when a refinery receives an incoming voltage with a substantial deviation from the nominal value. This causes the equipment to operate either in undervoltage or overvoltage conditions. Either way, the connected pieces of equipment could suffer direct damages or a fast-decreasing lifespan. 


Power quality issues must be treated seriously as it eventually affects a refinery’s operational cost. Without mitigative measures, an unstable power supply can decrease the efficiency of the refinery. In simple words, it’ll take much more energy to turn crude oil into petroleum products.

The Ashley Edison (UK) Solution

Voltage fluctuation, undervoltage, overvoltage and other irregularities can be mitigated with proper voltage optimisation equipment. The automatic voltage stabilizer is an ideal solution that offers a clean and stable incoming power supply to refineries. It compensates for any irregularities from the local grid and ensures that oil refinery process control systems are operating with the required nominal voltage. 


Ashley Edison (UK) has been providing industry-leading voltage optimisation equipment to various industries since 1977. Our expertise in mitigating voltage drops, fluctuations and other irregularities has found its way to organizations of different sizes. Our range of voltage optimisation equipment remains pivotal in maximizing the operational efficiency and power quality of many companies. 


In this case study, we’ll highlight how two different series of Ashley Edison (UK) automatic voltage stabilizers have helped leading oil and gas companies in resolving their power quality concerns.

The OSES Series

voltage optimisation automatic voltage regulator manufacturers

The OSES series is a single-phase servo-type automatic voltage regulator designed for reliability in rugged environments. It’s capable of maintaining 1% regulation accuracy or better, for incoming voltage deviation of up to 40%. Besides its high-precision regulation, the OSES Series offers a high response rate to prevent eventualities of overshoot.

The IVSI Series

Magnetic Induction Voltage Stabiliser

The IVSI Series is an industrial-grade voltage optimisation equipment for 3-phase applications that demand highly precise output regulation. These automatic voltage stabilizers are based on the magnetic induction design, which boasts reliability, and low operating costs for a huge range of applications. Not only does the IVSI Series provide 1.5% regulation accuracy, but different models are also available to support a wide range of input voltage swings.

Use Cases

Ashley Edison (UK) is no stranger to the P.O.G. industry. We’ve been involved in the installation and commissioning of voltage optimisation equipment for major oil refineries. Here are three notable cases from renowned oil & gas clients of ours.

automatic voltage stabiliser voltage fluctuation
BP Logo

Case #1:

British Petroleum In Georgia (2013)

British Petroleum ventured into Georgia’s O&G market in 1996. Since then, it has been operating the BTC, SCP and WREP pipelines along with the Supsa Terminal for crude oil storage. In 2016, BP marked its 20th anniversary in the country by injecting a $2 billion investment into the SCPX project.

During a facility expansion in 2013, BP ran into a problem with voltage drop due to an excessively long cable run. The additional cable length has caused the voltage to drop below the nominal value and introduced operational issues. 


For example, the motor pumps were unable to operate efficiently due to the low voltage level. Such issues disrupted the refinery’s operation and may negatively affect its financial performance.

To compensate for the voltage drop, we’ve installed 1 unit of OSESL series 1,000 kVA automatic voltage stabilizer. This voltage optimisation equipment is housed in an outdoor IP54  (BS / EN 60529) / NEMA3 compliant enclosure, which ensures reliable operation even in the harshest condition.

With the OSES automatic voltage stabilizer installed, our client’s load begins receiving highly accurate regulated voltage at ±0.5% accuracy.

automatic voltage stabiliser
AshleyAsia_Clients__0006_Total SA

Case #2:

Total S. A. in Angola (2012)

Total S.A. is one of the largest petroleum companies in the world and has maintained a presence in Angola since 1953. It’s primarily active in exploration & production, gas & power and renewable energies.

Total S.A. grappled with fluctuating incoming voltage for its new commercial building. In what’s suspiciously a power quality issue from the local grid and an isolation transformer configured for a full load, the building’s voltage experienced a fluctuation of up to 500V. The huge spike leads to a shortened lifespan of the connected loads and causes disruptive breakdown that impacts operational efficiency.

Upon investigation, we’ve recommended that the IVSI series of oil-immersed magnetic induction voltage optimisation equipment be installed at the building along with the main switchboards. Our team is involved in implementing the following setups to mitigate the effects of fluctuating incoming voltage : 

  • Automatic Voltage Stabilisers (Model: IVSI Series)
    •  1,000 KVA x 1 unit
    • 1,250 KVA x 5 units
    • 2,000 KVA x 2 units
  • Main Switchboards x 8 units (1,000 KVA up to 2,000 KVA)

As expected, the fitting of these voltage optimisation equipment ensures that the building receives a stable and clean power supply.

voltage fluctuation

Case #3:

Esso In Angola (2017)

Esso’s interest in Angola spans over 2 million acres of deepwater blocks. The petroleum company produced an average of 169,000 barrels of oil in 2016.

In 2017, Esso is facing voltage fluctuation at its facility that is attributed to load changes. The irregular power supply posed operational issues to sensitive and critical loads.

The problem was completely resolved with the installation of 3 units of 2,500 KVA IVSI series magnetic induction voltage stabilizer.

With the magnetic induction voltage optimisation equipment commissioned, Esso enjoys a stable, clean, and uninterrupted power supply at its facility. Naturally, sensitive equipment operates reliably and is no longer at risk of a shortened lifespan.


It is evident that a stable, clean and constant voltage supply is crucial for operational efficiency and safety of the power, oil & gas industry. We couldn’t stress more about the importance of automatic voltage stabilizers to protect the facilities and the interest of stakeholders involved.


Talk to us to learn more about industrial-grade voltage optimisation equipment for the power industry.

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Stay Safe With Greater Protection

As safety is our utmost priority, Ashley Edison prepares for every scenario possible
—taking the puzzle out of your protection.

Designed And Engineered With Safety In Mind

We leave nothing to chance when it comes to larger capacity units (≥400KVA). By installing high-quality protective acrylic shields in front of live parts, we ensure the safety of your personnel at all times. For enhanced protection during installation, all distances between uninsulated metal parts, busbars, and cable sizes are compliant with IEC61439-1 and IEC 61439-2 guidelines.

Outfitted with fireproof cable trunking, this protective solution safeguards against long fire exposure even in hazardous areas and explosive atmospheres—providing maximum safety for mission critical applications.

Fuss-Free Installation. Seamless Operations.

To ensure ease of installation, Ashley Edison addresses the concerns of contractors and installers by keeping it simple.



We keep the installation process simple and streamlined by allowing sufficient working space for installers. Taking the nut and bolt intrusions into consideration, we ensure that the distance between the uninsulated metal parts, the busbars, and cable sizes are compliant with IEC61439-1 and IEC 61439-2 guidelines.


Even in units with larger capacities, all busbar terminals are clearly marked out, and well positioned in line for easy identification of individual input and output terminations. Installation of these terminations are similar to those practised in high voltage transformers.

Easy Maintenance

Annual Ocular Maintenance
Visual Inspection 230

Conduct Visual Inspection On Voltmeter:

Ensure reading is set to your desired set output voltage value (e.g. 230V).

LED Status

Ensure LED Status Indicators are at “Normal”.

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Visual Observation Of Variable Transformer Surface:

Use airbrush for dusty environments if necessary.

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Visual observation if carbon brush is not worn out.

Moving Motor

Conduct visual inspection to check variable transformers are all regulating (moving).


Accuracy. Beyond Imagination.

The digitally enhanced Ashley Edison MBB Card ensures pinpoint voltage stabilisation against the most erratic anomalies, allowing you to protect precious uptime, effortlessly. Harnessing ultra precision capabilities to produce some of the tightest output voltage tolerance available in the industry, the Ashley Edison MBB Card delivers ±0.5% voltage accuracy, enabling your load equipment to enjoy optimal voltage supplies, regardless of load change in your electrical system.

Expert Digital Control

Utilising the advantageous measurements of true RMS, the Ashley Edison MBB Card’s reads both perfect, sinusoidal waves, as well as complex, distorted non sinusoidal waves—up to 0.1V accuracy. Coupled with lightning fast response time of 1.5ms, this expert digital control feature equips your load with total voltage protection that is precise, continuous and ultra responsive.

AE Digital Control Display_230v

Universal Presettable Function

The Universal Presettable Function onboard the Ashley Edison MBB Card allows seamless control of your desired output voltage value on all 3 Phases—with just a touch of a button. This multifunctional feature enables each AVR to fully operate with just 1 card, instead of separate cards for each individual phase. Fitted LED Output Voltmeter Display and Alert Indicator better facilitates easy status monitoring while performing maintenance on your AVR.


Microcontroller Unit (MCU)

MicroController Unit (MCU) helps you to deliver high speed and reliable efficiency in the AVR’s operations with less heat generation and reduced power consumption. Used in Supercomputers, Surface Mount Technology (SMT) allows components in the Ashley Edison MBB Card to be aligned closer together, creating a more compact and lightweight end product. Additional safety wire-to-board feature establishes fail-proof connectivity between circuits—so you can work safely on your AVR.