T H E O F F I C I A L P U B L I CAT I O N O F
12
Save Money With
Substation Maintenance
22
Grid-Tied Wind Energy Systems
28Distributed Energy
Storage and Utilities,
Commercial Buildings
Intelligent Load
Management
YOUR POWER DELIVERY MEDIA SOURCE
S
BY CURT HICKCOX,
public UTILITIES MAINTENANCE INC.
T
he electricity delivery system operating in the U.S. and the rest of the
world is one of the greatest engineering
feats in history. Its design, construction
and reliable operation is one of the most
critical assets to our daily lives.
This system, the electric grid, comprises high-voltage transmission circuits
mainly supported by steel structures that
transport electricity from the generation
plants to substations where transformers, breakers and other equipment adjust
the electricity’s voltages before it is sent
to distribution lines and structures that
deliver the electricity to homes and businesses. This system is the backbone of
the power d
­ elivery system that connects
and interconnects each utility company
with its customers.
In the U.S. alone, there are more
than 200,000 miles of high-voltage
transmission lines, 10,300 transmission
substations and 2,200 distribution substations. Substation equipment includes
some 12,200 autotransformers, 195,000
oil circuit breakers, 64,000 transformers, 26,000 voltage regulators, plus the
associated structural steel, bus-work,
switchgear and ­
foundations. Virtually
all the equipment is made of painted
steel that is susceptible to corrosive
attack from atmospheric exposure.
Even the structures, often constructed
of galvanized steel, are subject to corrosive deterioration. Because corrosion
causes equipment failures that result in
service disruption, electric utilities must
minimize corrosion through practices
that include engineering design during
construction and installation, as well
as established maintenance programs
throughout the service life.
The direct cost of corrosion in the
U.S. electric transmission and distribution segment is some $700 million
annually. Many U.S. electric utilities
maintain their substation and distribu-
Curt Hickcox is vice president of Public Utilities Maintenance Inc., an SSPC-certified and
ISO-registered corrosion control contractor specializing in the global electric transmission and
distribution industry. He is a member of IEEE, NACE and SSPC and is chairman or vice chairman
of three joint task groups responsible for transmission and distribution coatings-related standards.
For more information, visit www.puminc.com. Reach Hickcox at curthickcox@puminc.com.
tion assets by preventing and controlling corrosion. They understand the
criticality of substations to their system
reliability and how corrosion can damage these components. But often and
for various reasons, utilities are reactive
rather than proactive when dealing
with corrosion. Dealing with corrosion
can be expensive, and dealing with it
after the fact only increases the cost. But
these expenses pale compared with the
costs of a failure and resulting service
outage. Properly planned and executed
prevention programs control and minimize upfront expenditures while maintaining system reliability.
Corrosion is controlled primarily
through painting and generally is considered a maintenance, operational or
revenue expense. Unfortunately, most
utilities fund these types of expenses
only minimally because they usually
are considered a charge against profit
rather than a profit generator as a capital
expenditure would be. Available funds
are funneled toward expenditures that
help the bottom line, but the bottom line
suffers more as the result of a corrosionrelated failure than by spending money
upfront on prevention and maintenance.
Construction of the U.S. high-volt- electric customers are spending 43 perage transmission system and its corre- cent more than they did in 2002 to build
sponding distribution system peaked in and maintain the electric infrastructure.
Since then, the number of power outages
the 1970s (see figure).
Most transmission lines were built has remained infrequent, but it takes
from the 1960s through the 1990s. longer to restore service. One conclusion
Nearly 75 percent of the North is the system is not being maintained
American electric grid was built dur- and upgraded in a way that improves
ing these 40 years. The age of these its reliability. It’s another indication of
transmission lines and their large num- a reactive approach: spending money
bers will increase the amount of main- to fix a problem rather than spending
tenance work required to keep the it to prevent one. Since 2002, there has
system safe and reliable. Because there been a 15 percent increase in the annual
are so many substations
number of minutes the
of the same general vinaverage customer is withService
tage, many will require
out power (although the
interruptions
corrosion repair during
number of outages slightly
can be
the same time, which
decreased), but spending
prevented
will stretch resources
per customer on local diswith correct
and budgets. A utility
tribution equipment and
inspections
can control its spending
maintenance rose at twice
and proper
at a more consistent rate
maintenance. the rate of inflation. This
by being proactive with
seems to indicate that
its maintenance program, which will because of the distribution system’s age,
allow for better planning and cost- it is getting more expensive to maintain
effectiveness that will result in higher the system’s high level of reliability.
reliability and profitability.
Although the U.S. electric distribution
A recent Associated Press study found system has serious corrosion issues, it is
not all gloom and doom. Many utilities
have implemented programs to deal
with corrosion in their substations and
have eliminated corrosion-related service disruptions. Industry organizations
such as the International Electronic
and Electrical Engineers Association
(IEEE), the Electric Power Research
Institute (EPRI) and the National
Association of Corrosion Engineers
(NACE) have established task groups
and are researching and publishing
standards relating to substation corrosion. The federal and state regulatory
agencies also have started taking note of
the ­condition of the electric grid, and,
in some cases, have begun to mandate
remediation and improvements. Proven
methods of controlling corrosion exist,
and with a little effort and dedicated
funding, corrosion-related electric service disruptions can be eliminated.
The first step is to assess the distribution system. A utility must understand
the condition of its system before it can
determine what needs to be done and
the cost. The assessment should include
a visual inspection of the system components, a condition rating per industry
guidelines, prioritization based on the
utility’s requirements (i.e., component
criticality, condition, logistics and outage limitations), surface preparation and
coating system requirements and cost
estimates. Simple testing, such as for
lead in the existing coatings and coating film thickness and adhesion, should
be performed as part of the assessment.
NACE and IEEE joint task groups are
writing standards that reference corrosion control in the transmission and
distribution industry that include details
on performing coating assessments on
transmission and distribution structures.
These standards should be published by
the end of 2013.
Once the assessment is complete,
a defined program can be developed
using a specific time frame and other
criteria that conform to the utility’s
long-range plans. Upon funding, a project scope can be assembled easily using
the assessment as its basis, followed
by job award to a qualified contractor. It is critical that only contractors
and workers with specific substation
training and experience be allowed to
bid on this work. Aside from demonstrated capabilities in preparing and
coating complex electric distribution
equipment, the contractors must have
excellent safety records with health and
safety programs specific to substation
structures and equipment. The project
specification must be tailored to the
scope and not generic. A coating schedule that details surface preparation and
coating system requirements is integral
to the specification, as is a listing of all
applicable safety rules and regulations.
Various surface-preparation methods for steel surfaces may be employed
in a substation. Power washing and
abrasive blasting should not be used
in an operating substation because of
potential safety and damage issues. The
Society for Protective Coatings (SSPC)
has published surface-preparation standards widely specified throughout the
industrial coatings industry, and certain
standards ranging from solvent cleaning to hand and power tool cleaning
to chemical stripping are applicable in
substations, as well. The idea is to have
a clean, dry, sound substrate free of contamination, peeling and flaking coatings
and loose rust before application of the
new coating system. The unique configuration and sensitive nature of many
types of electric distribution equipment,
especially transformers and their cooling
radiators, can make it difficult to properly prepare before coating, but many
methods are available to prepare the
surfaces. Again, a contractor with specific experience in transformer painting
is crucial to the project’s success.
The application of protective coatings also presents challenges because
of equipment configuration, as well as
procedural and safety constraints associated with working near energized
electrical equipment. Spray application usually is not allowed, and the
standard hand methods of coating
application such as brush and roller, although acceptable on breakers,
tanks, etc., are not conducive to proper coating coverage on radiator banks.
Flow coating, a specialized paint application technique, is a process similar
to dipping radiator tubes. A recirculating system comprising a low-pressure pump, hoses, specially designed
nozzle and collection setup allows the
coating to reach and covers nooks,
crannies and crevices on the radiator
tube surfaces. Proper and consistent
paint viscosity is required. Although
the process is complicated, it is the
only application method available for
field use that ensures complete coverage of a radiator’s surface area. The
thickness of the paint film is impor-
tant because a too-thin film does not
provide adequate corrosion resistance,
and a too-thick film can interfere with
radiator cooling efficiency. No other
method of field application can access
and coat these areas, and only a contractor experienced in this application
method should perform flow coating.
Flow coating also is used for surface
preparation on the radiators because
often chemical stripping is the only
way to remove suspect coatings from
surfaces inside the fin banks where
hand-cleaning methods cannot access.
The U.S. has an electric transmission and distribution system made
of aging structures and equipment.
Service interruptions because of failures from c­orrosion are a fact, but
they can be prevented by a proactive
approach that includes correct inspections and proper maintenance. Proven
methods of ensuring the long-term,
cost-effective protection of the system
exist. Experience has proven the viability and benefits of formal maintenance
coatings programs for steel substation
structures and equipment.
Eprinted and posted with permission to Public Utilities Maintenance, Inc. from PowerGrid International
October © 2013 PennWell Corporation
Public Utilities Maintenance, Inc.
What can we do for YOU?
where others see rust...
we see a blank canvas.
Public Utilities Maintenance, Inc. offers corrosion control
solutions in different industries. Please look at our list of
services below to see if we can help you. Please contact us
for more information.
Steel Structure Coatings, Footing Inspection
and Repair Specialists.
Since 1992 Public Utilities Maintenance has met the unique
painting needs of the Utility Industries: Electric, Gas,
Communication, Water, and Fuel, around the world. Our
Management team have over 100 years combined experience
working on and managing painting projects.
Certifications:
• ISO 9001:2008
(Quality Management System)
• SSPC - QP1
(Field Application Coatings)
• SSPC - QP2
(Industrial Hazardous Paint Removal)
Services We Provide
Painting / Coatings Services:
• Transmission Towers & Steel Poles
• Substation Structures & Equipment
• Flow-Coating Transformers
• Antenna / Microwave Towers
• Power & Gas Plants
• Tanks & Piping (Water, Gas, Oil, Penstock)
• Elevated Structures
Lead Removal:
• Regulatory Compliant
• Containment Design & Installation
Specialized Services:
• Coatings / Corrosion Inspections
• Steel Plate & Lattice Member Fabrication
Public Utilities Maintenance, Inc.
212-26 99th Avenue
Queens Village, NY 11429
Office: 718.740.4540
Fax: 718.740.5790
Email: info@puminc.com
Website: www.puminc.com