Sentinel (ICU)TM

Removes water from oil and paper Insulation

Removes acids and oxidation by-products.

Removes unstable Sulphurs (DBDS, Elemental Sulphur)

Removes low level PCB

Restores insulation properties

Protects against degradation

Extends asset life

Global Transformer Solutions Ltd.

The world leaders in Online Processing

What is Sentinel (ICU)™ ?

Sentinel (ICU)™ Is a family of transformer oil reclamation (sometimes called regeneration) systems.Designed using the exclusive adsorbent media developed specifically for the removal of water and polar contaminants from the transformer oil and the solid insulation (paper) in the transformer.

Designed for ease of installation, operation and change out, Sentinel (ICU)™ Is a patented, online system that is installed on a transformer and makes use of the physical and chemical actions that are going on inside the transformer to assist and optimise the removal of contaminants. Sentinel (ICU)™ uses our patented and exclusive world leading adsorbent media giving Sentinel (ICU)™ an unrivalled ability to trap and remove contaminants.

What is Transformer oil Reclamation (regeneration)?

These two terms are often used interchangably and simply mean the restoration of the transformer oil to a “near new” condition. Reclamation means to restore the oil in the transformer to that of a similar condition of the original oil when it was initially installed, with key properties as defined in a standard. (See our technical paper – ‘What do standards tell us’ – GTS-TP-001.)

Are Our Transformers at risk?One of the major reasons that transformers fail is that the conditions affecting the most vulnerable part of a transformer (the paper insulation) often go unrecognised.To understand why this is we need to look at what causes transformer insulation to fail. (See our technical paper – Why do transformers fail?– GTS-TP-002). One of the greatest hazards to transformer reliability is the dissolved moisture content. It is no coincidence that dissolved moisture is also the largest contaminant by volume in transformer insulation.

At Risk

70

60

50

40

30

20

10

0

Adsorbent Capacity % weight

GTS- Sorb Zeolite Dri-RiteActivatedBauxite

2

Transformer life

Transformer life is directly related to the life or strength of the cellulose or paper insulation materials used in the construction of the windings. They provide the mechanical strength that supports these critical structures. Conductors of a transformer are typically wrapped in Kraft paper.

Paper provides: • Mechanical strength• Dielectric Strength• Dielectric Spacing

N.B. Once paper life has been lost it cannot be restored !

See Technical Paper GTS-TP-003 – Understanding the water hazard.

Press board cylinders support and separate the windings from the core.

Press board spacers support the windings.

The progression of insulation failureControlling Factors

Dissolved Moisture Heat

Oil impregnated paper(Cellulosic insulation)

Chemical degredation (Acids, Peroxides, O2, Furanics etc.)

Mechanical degredation

Dielectric degredation

Added Moisture

Acids ( polar materials)

Corona (Glow discharge)

Insulation failure

Coduction and Ionisation ( Partial discharge)

Understanding Dissolved Moisture.

It is dissolved moisture in the transformer insulation that is of the greatest concern. It exists in the oil (this is where it is measured when the oil is sampled and analysed) and in the solid or paper insulation.Transformer oil (or any insulating fluid) will only hold a certain amount of water and this is known as the saturation level of the oil. The amount of water that can be held also varies with temperature.

3

More than 95% of the moisture in a transformer is in the solid (paper) Insulation.

Moisture in the paper insulation.

Measuring the moisture content of the paper insulation is not as simple as measuring it in the oil. It is possible however to obtain a reasonable indication of the moisture content of the paper insulation of the windings by using calculation. To do this it is Important that the temperature of the oil sample at the time it is taken.Once we know the temperature of the oil sample and we have the moisture content of the oil from analysis an indication of the water content of the paper insulation (measured as % Moisture by dry weight - %M/dw) can be obtained.

The other paper insulation “Killers”

As transformer oil ages it oxidises. The by-products from oxidation that form in the oil and become deposited in and on the paper insulation are also harmful to the health and strength of the paper insulation and these should be removed at the earliest possible stage of formation if we want to minimise the risk of failure and maximise the asset life.These killers are identified in analysis by:Acid, DDF, IFT.

4

Example of Moisture Content and the effect of temperatureTransformer oil mass =20,000kg, Dry insulation mass = 1,000kg ( ratio 20:1)

Moisture Content(ppm)

Oil Sample Temperature (ºC)

Water in Oil ( % Saturation)

Water mass in oil (mg)

Water in Paper (%M/dw)

Water Mass in paper insulation (kg)

Analysis 1 25ppm 25 ºC 33% 500mg 3.3% 33kg

Analysis 2 25ppm 20 ºC 45% 500mg 4.25% 42.5kg

The effect of temperature can be significant. This is why it is essential to fully understand the moisture state of a transformer when deciding upon what action to take.

Any in service oil will have some level of oxidation present an indication of this is often the oil colour.

To reduce the risk of failure and to maximise the asset life we need to: -

• Remove and prevent the formation of excess water • Remove and prevent the formation of oxidation by products• Maintain the oil in healthy and contaminant free condition.

The Solution = Sentinel (ICU)™

Only Sentinel (ICU)™ deals with all these issues in a single unit and does it: -

• Online• Continuously• Without affecting DGA • Without the necessity of an outage

5

Typical Neutralisation Number NN ( Acidity) - mgKOH/gm and Colour guide

0.01-0.1 0.05-0.1 0.11-0.15 0.16-0.4 0.41-0.65 0.66-1.5 >1.5

Pale Yellow Yellow Light Amber Amber Brown Dark Brown Black

Good Prop A Marginal Bad Very Bad Extremely Bad Class 7 Oils

Our experts at GTS and our worldwide net-work of distributors are able to advise clients on the most appropriate Sentinel (ICU)™ for any application.

With hundreds of units fitted in conditions ranging from arid lands to tropical rain forest. From Arctic cold to Desert heat, you can be assured of a proven, reliable solution to the challenges of maintaining your transformer fleet. Sentinel (ICU)™ is successfully installed and protecting transformers from 250kVA to 1,100MVA.

Sentinel (ICU)™ Installation

This is a typical installation for Sentinel (ICU)™ P which is the pump equipped version. Our experts will advise on whether a pump may or may not be required dependent upon the situation.

Installation of the Sentinel (ICU)™ can often be done with no need for an outage, depending upon clearances.

Changing the Sentinel (ICU)™ column can be done, once installed, whilst the transformer remains in service.

Our engineers are available to train client’s staff in how to install Sentinel (ICU)™ . A typical Sentinel (ICU)™ installation takes between 2 – 6 hours. Alternatively, many of our distributors provide an installation service. Either way we ensure that the installation is completed to the client’s requirements.

When should the Sentinel (ICU)™ column be changed?Change intervals can be scheduled based upon oil analysis results. Where Sentinel (ICU) Smart Sentry™ is installed, the sensor system will provide change out notification.

6

Which conditions are suitable for Sentinel (ICU)™ Installation?

Sentinel (ICU)™ Family of online transformer reclamation oil systems

7

Which Sentinel (ICU)™ is right for you?

The Sentinel (ICU)™ No more need for annual vacuum purification or energised regeneration of transformers. With The Sentinel (ICU)™ installed there is no requirement for these types of oil maintenance operations and the transformer is protected 24/7/365.

Other major benefits are that it is low cost, easy to install and change.

The next step.

Take advantage of our free assessment offer.

Send us the latest analysis report for your transformer and let our experts advise on whether The Sentinel (ICU)™ is suitable and appropriate for your specific circumstances.

Don’t forget, we are still the only manufacturer that provides a 100% refund if a Sentinel (ICU)™ that we recommend, does not do what we agree it will.

For further information or to get copies of case studies and technical papers please visit us at www.txglobal.co.uk or email us on info@txglobal.co.uk.

Head Office: Strathleven HouseVale of Leven Industrial EstateDumbarton, Scotland, United Kingdom.G82 3PD.Tel: +44 (0) 2071 181 223Email: info@txglobal.co.ukWebsite: www.txglobal.co.uk

8

Global Transformer Solutions Ltd.

The world leaders in Online Processing

Distributed in your region by:

2 Duiker Avenue, Rustenburg, 0299North West ProvinceRepublic of South Africa.Email: ZenMining@Gmail.comTel: +27 (78) 746 6638