How Automatic Voltage Regulators Changed The Solar Industry


How Sterling and Wilson Solar leveraged Automatic Voltage Regulators to overcome Voltage fluctuations


Case Study for Sterling and Wilson Solar

Blessed with over 300 days of sunshine and a subtropical climate, Queensland, Australia has become an increasingly popular place for Renewable Energy Companies like Sterling and Wilson Solar to establish numerous solar farms. 


As of 2020, the company has three solar farm projects with more than 800MW under construction in the region, and more are expected to be built. The Queensland State Government now aims to generate half of its energy from renewable sources by 2030.


The Problem:

Inconsistent Sunlight Resulting In Voltage Fluctuation


However, the same abundance of sunshine in the State also presents some potential problems in a solar farm’s operations.


In a nutshell, when the Earth receives energy directly from heat generated by the sun, the solar panels collect sunlight and convert it into electricity. 


However, while there are many days of sunshine, the amount of voltage that is received from the solar panels is never stable—because this depends on the position and intensity of the sun. 


Thus, the amount of sunlight received by the solar panel is inherently inconsistent. 


Depending on the amount of sunlight the solar panel receives, this could lead to voltage fluctuation that is harmful to sensitive electronics and load equipment. 


This is why it is important to have voltage optimisation equipment in between the solar panel’s output, and the battery’s input. 


This enables optimal output voltage regulation from the solar panels.


The Ashley Edison Solution


This need for voltage optimisation equipment led Sterling and Wilson Solar towards Ashley Edison. 


To ensure that the solar project achieves the best results with completely stabilised voltage, Ashley Edison supplied Sterling and Wilson Solar with a series of Automatic Voltage Regulators (Servo AVRs).


This solution delivers highly optimised and controlled output voltage levels—that protect the batteries and other load equipment from harmful voltage anomalies.


The Automatic Voltage Regulators also made sure that the voltage from the solar panel never exceeds the safe value required by the batteries for charging.


Highly ideal for remote locations because little to no maintenance is required, the units supplied to Sterling and Wilson Solar were also slightly oversized capacity rating to mitigate any risk of overheating—which hugely reinforces the Servo AVR’s outstanding durability. 


The Ashley Edison solution provided for Sterling and Wilson Solar’s Project—was a series of customized Automatic Voltage Regulators (Servo AVR).





  • Single Phase Servo Electronic Automatic Voltage Regulators
  • Model: SES-5H-S20
  • Quantity: 40 Units
  • Rating: 5 KVA
  • Fast Response Time (<1.5ms)
  • Inbuilt High Overload Capability (10x max current rating for 2 seconds)
  • Endurable NEMA 1 Style Enclosure – BS EN 60529 


The Results


The Ashley Edison Automatic Voltage Regulators designed for Sterling and Wilson Solar deliver immediate results upon installation:


  • Stepless & Automatic Voltage Regulation.
  • Compensation for Low Voltage (from 192V).
  • Complete Stabilisation for High Voltage (covering up to 288V).
  • Stable 240V, ±1% output voltage accuracy.
  • Total protection against harmful high energy surges, transients and spikes.


These Servo AVRs continue to be fully functional, regardless of days with lower intensity of sunlight in Queensland.


Additionally, the Servo AVRs ensure load equipment with safe operations without fear of reverse current flow. This solution also enables Sterling and Wilson Solar to no longer worry about potential voltage fluctuations caused by inconsistent sunlight, and focus more on their goals.


With a stable and optimised voltage supply, Sterling and Wilson Solar continues to gain momentum in enhancing renewable energy efforts—not only in Australia but throughout the World.





Superb voltage quality can play a huge part in elevating renewable energy operations—essentially protecting the Earth for future generations. This case study demonstrates how fluctuation-free voltage supply is vital in promoting productivity and sustainability for society.


With a wealth of over 40 years of experience in expert voltage control, Ashley Edison continues to inspire absolute voltage optimisation across global organisations in multiple industries worldwide.


For a comprehensive consultation, drop us an email at [email protected] and discover how you can effectively solve your power problems with our wide range of voltage solutions.


To learn more about Ashley Edison’s Automatic Voltage Regulators, visit our product page here.


“Demand Certainty, With Voltage Stability.”




Sterling and Wilson Solar
AVRs | 40 units of 5KVA Units
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Three Phase

SESL-H-3P-S Model
Large Capacity Rating
200 to 2,000 KVA


Enclosure 335
1000W x 1300H x 580D (mm)
250~300 KVA ± 15%
120~200 KVA ± 20%


Enclosure 336
1280W x 1480H x 660D (mm)
400 KVA ± 15%
250 KVA ± 20%


Enclosure 337H
1880W x 1950H x 880D (mm)
500 KVA ± 15%
300 KVA ± 20%


Enclosure 339
1470W x 1950H x 1340D (mm)
600 ~ 1,500 KVA ± 15%
400 ~ 1,000 KVA ± 20%
300 ~ 750 KVA ± 25%
300 ~ 600 KVA ± 30%

Three Phase

SES-H-3P-S Model
Added I/P Breaker Protection
60 to 1,000 KVA


Enclosure 333
490W x 800H x 990D (mm)
≤ 100 KVA ± 15%


Enclosure 334
540W x 900H x 1000D (mm)
120 – 150 KVA ± 15%


Enclosure 335
1000W x 1300H x 580D (mm)
180 – 300 KVA ± 15%
120 – 200 KVA ± 20%
120 – 150 KVA ± 25%


Enclosure 336H
1880W x 1480H x 660D (mm)
400 KVA ± 15%
250 KVA ± 20%
180 ~ 200 KVA ± 25%


Enclosure 337H
1880W x 1950H x 880D (mm)
500 KVA ± 15%
300 KVA ± 20%
250 KVA ± 25%


Enclosure 339H
2170W x 1950H x 1340D (mm)
600~1,000 KVA ± 15%
400~600 KVA ± 20%
300~400 KVA ± 25%

Single Phase

SES-H-S Model
Added I/P Breaker Protection
1 to 100 KVA

Enclosure 102
270W x 460H x 490D (mm)
≤ 20 KVA ± 30%
≤ 15 KVA ± 20%
≤ 10 KVA ± 25%
≤ 10 KVA ± 15%

Enclosure 103
400W x 580H x 500D (mm)
25 KVA ± 15%
20 KVA ± 20%
15 KVA ± 25%

Enclosure 332
380W x 670H x 780D (mm)
30 KVA ± 15%

Enclosure 333
490W x 800H x 990D (mm)
40 ~ 50 KVA ± 15%
25 ~ 30 KVA ± 20%
20 ~ 25 KVA ± 25%
15 ~ 20 KVA ± 30%

Enclosure 334
540W x 900H x 1000D (mm)
60 ~ 75 KVA ± 15%
40 ~60 KVA ± 20%
30 ~ 50 KVA ± 25%
25 ~ 40 KVA ± 30%

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.