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Sustainable Electric Power for the
Emerging Markets
WHITE PAPER
© 2017 AGC Refining & Filtration LLC

AGC REFINING & FILTRATION
SUSTAINABLE ELECTRIC POWER FOR THE EMERGING MARKETS 2
Contents
Abstract 3
A Master Plan 3
Transformer Maintenance 9
Summary of Required Equipment and Parameters 13
Security 14
Conclusion 15

Abstract
Lack of power impacts annual growth rates, slowing the development of new businesses and inhibiting
new investment. The demand for power can lead to new investments in large-scale power projects in
addition to creating markets for smaller generators of power.
The purpose of this white paper is to present a master plan for a practical and cost-effective solution to
maintaining the existing power infrastructure in good operating condition. This plan is applicable for all
providers of electricity in the local community. The solution centers on the two most important aspects of
power transformer maintenance:
 A diagnostic program
 A preventive maintenance program
The paper will show that these two aspects can be implemented economically without the purchase and
use of expensive and complicated equipment.
The solutions presented have been implemented worldwide and have proven effective in reducing the
cost of providing electricity.
The Management of the Allen Group
January 2009
A Master Plan
This white paper presents a master plan for the improvement of the reliability of a local community’s
power transformers. It consists of:
1. Diagnostic methods (a description of required methods and diagnostic equipment)
a. Infrared scans
b. Moisture detection
c. Fault gases detection
d. Acidity detection
e. PCB detection and elimination
2. Transformer maintenance (a description of a comprehensive maintenance plan)
a. A routine maintenance program and the equipment required
b. Tap changer filter systems
3. A plan for increased security at unmanned substations
a. The installation of perimeter security cameras and lights
b. The installation of a remote sensing network interconnecting the security cameras
Diagnostic Methods
Two of the most important types of maintenance for insuring a long transformer service life are
preventative and reactive.
In practice transformer maintenance procedures combine preventive diagnostics with routine and
sometimes reactive maintenance. This combination is only effective when:

The necessary diagnostic equipment and skills to operate and interpret the results are available
The routine or reactive maintenance procedures using the proper equipment are applied properly and in
time
Such a plan has three elements:
1. Obtaining a baseline operating characteristic of the transformers (signature)
2. Determining the schedule for periodic re-testing or monitoring
3. Obtaining the basic equipment to insure regular monitoring
Transformers from different manufacturers can have great variations in their basic operating
characteristics. These differences are due to design, materials, and factory procedures. However, a
relatively low-cost preventive maintenance program can be implemented by investing in capital
equipment and the training of personnel.
Infrared Scans
If a transformer has been energized for a minimum of twenty-four hours, then a complete infrared scan
using an infrared camera should be done.
The complete scan should include:
 All wall surfaces
 All external bushings and connections
 All individual cooling systems
 Transition compartments
 Load tap changer compartment
 Control cabinet
 Power supply connections
 All other accessory devices
This infrared thermography scan should be performed a minimum of once a year for every transformer. A
typical infrared survey scan is shown below:
Figure 1: Typical Infrared Scan Showing a Hot Spot

Figure 2: Typical Thermal Imager
Equipped with a camera and voice recorder and optimized for field use in harsh environments, the thermal imager
delivers and stores clear images. Images are stored for download to a PC. A training DVD is included.
Moisture Detection
Moisture is one of the worst contaminants of insulating oil. If the oil is sampled for moisture at all, often a
single sample is taken and analyzed by the Karl Fischer Test. This test gives an absolute value of total
moisture content in parts per million or its equivalent in milligrams per liter. This value is meaningless
even if the oil temperature is recorded at the time the sample was taken. The reasons include the
following:
The absolute moisture content of the oil does not reflect the moisture content of the paper insulation
The result of the Karl Fischer test does not reflect the relative saturation of the moisture in the oil
The relative saturation is the percentage of full-water saturation (100%). This is the most representative
figure of the amount of moisture available in the oil for transfer into the paper insulation. At equilibrium the
relative saturations of both the oil and the paper are equal. (See also the white paper titled, Water Activity
In Oil)
The relative saturation must be recorded along with the oil temperature at the sampling point.
Oil temperatures at the top and bottom can also be recorded along with load to determine the
temperature in the insulation components. This data can be averaged over time to account for the slow
diffusion rate involved in the migration of water between paper and oil.
Figure 3: Hand-Held Moisture Meter
Measurement with the hand-held moisture meter is independent of oil type and temperature. Readings indicate
margin to oil saturation. In-line readings can be taken through a ball valve; there is no need to drain the oil. Meters
are made of rugged field construction.

Fault Gases Detection
Insulating materials inside a transformer break down and liberate gases into the insulating oil. The types
and distribution of these gases can be related to the type of electrical fault. The rate at which the gases
are generated can indicate the severity of the fault. This becomes a valuable tool in any preventive
maintenance program. After a transformer has been energized for a minimum of twenty-four hours an oil
sample should be taken for the dissolved gas analysis (DGA). This should be done at least twice a year.
More frequent testing may be needed if the DGA data indicate an increase in the rate of gases generated
over time.
Figure 4: A Typical Portable Dissolved Gas Analyzer
Compact and light, the portable dissolved gas analyzer analyzes for six different gases (acetylene, carbon monoxide,
hydrogen, methane, ethylene, ethane, and carbon dioxide) as well as total combustible gas (TGA). The unit performs
rapid measurements and requires only a small oil sample (50 cc).
Fault gases are generated inside a transformer by:
 Arcing
 Thermal heating
 Corona or partial discharge
The difference in these categories is the amount of energy that is released by the fault per unit time, per
unit volume. The most severe intensity of energy dissipation occurs with arcing, less with heating, and
least with corona.
Figure 5: Arcing Versus Corona
Arcing Corona
The fault gases that can be found in a transformer are shown in the following three groups:
1. Hydrocarbons and hydrogen
a. Methane

b. Ethane
c. Ethylene
d. Acetylene
e. Hydrogen
2. Carbon oxides
a. Carbon monoxide
b. Carbon dioxide
3. Non-fault gases
a. Nitrogen
b. Oxygen

Table 1: Typical Amounts of Gases Released During a Particular Fault
Hydrogen
Carbon
Dioxide
Carbon
Monoxide
Methane Ethane Ethylene Acetylene
Arcing in Oil 39% 2% 4% 10% — 6% 35%
Overheating in
Oil
16% Trace Trace 16% 6% 41% Trace
Overheating in
Cellulose
9% 25% 50% 8% — 4% Trace
Corona in Oil 88% 1% 1% 6% 1% Trace Trace
The concentration of fault gases in oil is dependent upon:
 The solubility of the gas in the oil
 The temperature of the oil
Hydrogen is the least soluble gas while acetylene is the most soluble gas in oil. Hydrogen can
accumulate in the space above the oil and create an explosion hazard.
The majority of these fault gases are generally very soluble in oil, which is very important to take into
account. Also, the solubility of gases increases with increased temperatures.
The following table shows the solubility of fault gases in transformer oil at static equilibrium of 30 inHg
(760 mmHg) and 77°F (25°C):

Table 2: Solubility of Fault Gases in Transformer Oil at Static Equilibrium of 30 inHg (760 mmHg) and
77°F (25°C)
Solubility Gas % by Volume
Least soluble, most flammable and dangerous
Hydrogen 7
Nitrogen 9
Carbon Monoxide 9
Oxygen 16
Methane 30
Carbon Dioxide 120
Ethane 280
Ethylene 280
Most soluble Acetylene 400
It is important to note that over a temperature range of 0 to 176°F (0 to 80°C) some gases increase in
solubility up to 79%, while others decrease their solubility by up to 60%.
Figure 6: A Typical Online Monitor for Dissolved Fault Gases
The monitor measures accurate and repeatable measurements of eight critical fault gases. In addition it correlates
moisture-in-oil, oil temperature, and ambient temperature to the transformer load. Supports IEEE and IEC diagnostic
tools for rapid warning and diagnosis of developing faults.
Online-dissolved gas analyzers are an excellent means for identifying problems at an early stage before
they become critical and irreversible. The information generated by the analyzer can be transmitted to a
SCADA system or via the Internet.
Acidity Detection
Moisture reacts with the sulfur in the presence of oxygen and—through a process called hydrolysis—
creates acidity. This is shown in a rise in the total acid number (TAN). The acid will promote sludge
formation and in turn, will deteriorate the paper insulation.

Figure 7: Dexsil Test to Determine Water Content of Transformer Oil
Quickly and easily quantify water content in oil with the auto-calibrated meter.
PCB Detection and Elimination
The Dexsil PCB/Chloride Analyzer is a field-portable instrument that incorporates an ion-specific
electrode to quantify chlorinated compounds. Powered by a rechargeable battery or AC power, it can
quantify chlorinated compounds from 3 to 2,000 parts per million (ppm).
Figure 8: A Typical PCB Detection Analyzer
Transformer Maintenance
Routine Maintenance
From the information given in the previous pages, it is evident that an economical maintenance program
can be simple and does not require a large budget. The most important part of the transformer is the
insulating oil. If this oil is correctly and regularly maintained then the transformers will likely last 30 to 40
years or longer.
A basic insulating oil maintenance program requires the removal of the major contaminants such as:
 Moisture
 Gases
 Solids
The only way to remove most if not all of these contaminants is by vacuum distillation.
This is a process whereby the boiling points of the contaminants in the oil are lowered while subjected to
filtration, heat, and vacuum.
This causes a phase-separation and a mass transfer, whereby the contaminants are vaporized and
discharged into the atmosphere. The resulting clean, dry, and degassed oil is returned to the transformer
while the transformer is on-line.

While there are many manufacturers that make a bewildering variety of vacuum systems, only a few have
proven to have a long track record of producing successful purification systems. Most are cheap
imitations that promise performance—usually at low cost—but fail after a short service life.
The only way to identify a good system is for engineers to become totally familiar with the principles upon
which the good quality systems are based. (See also the paper titled, Selection Parameters for Vacuum
Distillation Systems)
Equipment Required for Maintenance of Transformers and Tap Changers
Vacuum Distillation Systems
Allen Filters, Inc. manufactures two basic types of vacuum distillation systems:
1. A system for large power transformers
2. A system for medium- to small-sized transformers
A third type of vacuum distillation system is the multi-purpose vacuum distillation system.
The latter system can purify both turbine lubrication oil and transformer insulation oil using a proprietary
(patent pending) Allen Filters design. The systems are usually designed for operation in hazardous
(explosion-proof) areas.
The oil purification systems for the large transformers and those for the medium- to small-sized
transformers differ only in size. The process for both is fundamentally the same.
The process proceeds as follows:
1. While the transformer is on-line, the Oil Conditioner is connected to the transformer in a “kidney loop”
fashion, with oil flowing out of the transformer into the Oil Conditioner. After purification—either in a
single pass or in multiple passes—the oil goes through the Oil Conditioner and returns to the
transformer.
2. During each pass through the system, the oil is first filtered through a solids pre-filter, heated by a
low-watt density immersion heater and then subjected to high vacuum.
3. Contaminants are vaporized and ejected while the clean, dry, and degassed oil returns to the
transformer.
4. An optional fuller’s earth adsorption filter will neutralize excessive acidity in the oil.
5. In case a fuller’s earth filter is used, a final fine-solids filter is recommended to remove any finer
material that may have been generated.
6. Optional accessories are an on-line moisture analyzer and an on-line particle counter with the ability to
transmit system information and process data to a central location via the Internet.
7. The interconnectivity can be extended to the diagnostic data which the operator can download on a
laptop computer. The computer instantly transmits the data via the Internet to a central location for
diagnostic evaluation.
8. Alternatively, the data can be transmitted to Allen Filters, Inc. on a regular basis—via an Internet
link—for a no-cost evaluation of the transformer and tap changer conditions.

Figure 9: A Typical Large Transformer Oil Conditioner Mounted in a Trailer
Figure 10: A Large Transformer Being Prepared
for Purification
The purifier is inside the trailer.
Figure 11: A Typical Stationary Medium-Sized
Transformer Oil Purifier

Figure 12: Typical Multi-Purpose Trailer Mounted Systems
The Vacuum Distillation Process of the Allen Oil Conditioner
The standard process flow diagram for a transformer Oil Conditioner (see figure 13) shows a system that
is uncomplicated, fully automatic, requires a minimum of operator attention, and designed for some of the
most rugged terrain such as jungle, ocean, and desert conditions. The process is entirely controlled by a
programmable logic controller (PLC). All the operator has to do is hook up the inlet and discharge lines to
the transformer and then push the start button on the control panel.
A PLC accurately controls the right combination of heat and vacuum which is critical for the mass transfer
of contaminants from dissolved phase into the vapor phase.
The contaminants are condensed in the condensate tank upstream of the vacuum pump. This prevents
corrosive condensate from destroying the vacuum pump. The discharge pump returns the clean, dry oil to
the transformer. Options include a Fuller’s Earth Adsorption Vessel and a final filter. Allen Filters, Inc. Oil
Conditioners for transformer oil are fully automatic, reliable, and economical to purchase and operate.
Our equipment is at work in 57 countries around the world. In many cases equipment sold in the 1960s is
still operational.

Figure 13: Process Flow Diagram of an Allen Filters Oil Conditioner for Transformer Oil
Summary of Required Equipment and Parameters
Diagnostic Equipment
Infrared Camera
 A test kit for water content in oil
 A test kit for TAN
 A test kit for PCB detection
Oil Purification Equipment
 An Allen Oil Conditioner for transformer oil
 Trailer mounted, open, or enclosed
 A truck to pull the Oil Conditioner from one transformer to the next on a regular basis
Clean Transformer Oil Purification Parameters
 Dielectric strength: 56 kilovolt (kV) minimum, ASTM test no. D1816 with VDE electrodes at 0.08
in (2 mm) gap
 Water: 35 ppm maximum, ASTM test no. D1533
 Acidity: 0.03 mg KOH/gm oil maximum, ASTM test no. D974
 Flash point: 293°F (145°C) minimum, ASTM test no. D92
 Viscosity: 12 centistokes (cSt) at 104°F (40°C) maximum, ASTM test no. D88
 Specific gravity: 0.91 at 59°F (15°C) maximum, ASTM test no. D1298
Diagnostic Evaluations
Allen Filters provides a free diagnostic service for anyone. Just e-mail your oil quality data to
diagnostics@allenfiltersinc.com and we will provide you with a free analysis and diagnosis.

Security
Perimeter Security
Perimeter security for unmanned substations can be provided by a surveillance systems consisting of
outdoor day- and night-vision cameras, which are installed on poles along the four corners of the
perimeter fencing.
Video & Infrared Camera Equipment
The recommended system uses the new industry standard H.264 high-quality compression technology
for video storage and supports a full 30 frames-per-second live viewing and recording on all cameras.
Interconnectivity
At a resolution of 704 x 480, excellent detail is visible. The cameras provide clear color video during the
day and instant night vision in complete darkness. The system allows the ability to remotely view live and
recorded video from any high-speed Internet connection or third-generation cell phone. It is possible to
connect from any system using Microsoft Internet Explorer without the need to install additional software.
A software package is included that provides multiple simultaneous connections. This allows monitoring
multiple surveillance sites at the same time from one central location. The following pages show some of
the camera models:
Figure 14: Super High-resolution 550-line Bullet Security Camera with Night Vision
See up to 49 ft. (15 m) in complete darkness. Camera is weather proof and designed for outdoor use.
Figure 15: Long Range, High-resolution Zoom
See up to 197 ft. (60 m) during the day in normal color vision and up to 1,427 ft. (435 m) in complete darkness using
night vision. Zooms from 8 mm to 40 mm.

Conclusion
Sustainability is the objective of The Allen Group’s business through Allen Filters’s sustainability program
of providing our technology, equipment, and training at a reasonable cost to countries with emerging
markets.
The program’s objective is the improvement of those countries and communities in developing regions
through the transfer of technology for the productive use of affordable electricity and the stimulation of
local economic growth.

www.AGCInternational.com
3045 East Elm Street
Springfield, Missouri 65802, USA
Toll Free: +1 800 865 3208
Phone: +1 417 865 2844

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