Post on 15-Apr-2018
inExcellence ExecutionA C a s e S t u d y o f t h e B e t h e l - N o r wa l k T ra n s m i s s i o n L i n e
In a politically and emotionally charged climate,
NU was able to counteract the “Not In My Backyard” senti-
ments of local legislative, municipal, business and residential
interests. Through strong leadership and open communication,
the Bethel-Norwalk project was seen as necessary for the
greater good of the state and the region.
The new 345-kilovolt (kV) transmission circuit
uses two different underground cable technologies, including
the longest length of 345-kV solid dialectric underground
cable used in the U.S. NU also constructed two state-of-the-art
345-kV gas-insulated substations which reduced land and
space requirements.
The complex construction project begins to
reinforce the state’s electrical infrastructure, immediately
improves the long-standing reliability challenges in southwest
Connecticut, and makes the regional transmission grid more
secure and efficient — all while saving Connecticut consumers
millions of dollars in congestion costs.
According to Wall Street Access (January 12,
2007), “…Northeast Utilities is probably the foremost authority
on new transmission construction in the country. The company’s
efforts will reduce the import gap in Connecticut and allow new
generation and enable the re-powering of many aging oil/gas
units in the state.”
Bethel-Norwalk 345-kV Project
Leadership:
Innovation:
Advancements:
Contributions:
Northeast Utilities (NU) serves one of the most power-constrained
regions in the United States. Recognizing the need to meet the
area’s growing demand for reliable power, The Connecticut Light
and Power Company (CL&P), a wholly owned subsidiary of NU,
strengthened the transmission capacity in the southwest part of
the state on October 12, 2006, when it successfully energized its
new Bethel-Norwalk (B-N) transmission line.
In the 21-mile stretch between the southwestern
Connecticut towns of Bethel and Norwalk, there are
scores of schools, hundreds of businesses — and
thousands of backyards. Small wonder that a strong
“Not In My Backyard” mentality arose in opposition
to Northeast Utilities’ plan for improving the area’s
long-standing transmission reliability issues.
But this politically heated environment was just
one of the hurdles faced by NU. The Connecticut
Siting Council process resulted in a far more complex
project than originally anticipated: transmission lines
needed to alternate between overhead and under-
ground, and reduced land and space requirements.
With a combination of intense community outreach
and innovative technology, the B-N project is now
seen as a landmark achievement in U.S. transmission
projects. One of the largest transmission projects
recently completed in the country, the $340 million
B-N project was completed two months ahead of
schedule and more than $10 million under budget.
By making the regional transmission grid more
secure and efficient, while saving Connecticut
consumers millions of dollars in congestion costs,
the B-N project is truly an example of Excellence
in Execution.
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Leadership in Transmission
In October 2001, NU submitted the B-N project
application to the Connecticut Siting Council (CSC) as
an all-overhead 115-kV/345-kV double circuit transmis-
sion line located in the existing 115-kV right-of-way.
In June 2002, the Connecticut legislature passed a
law imposing a moratorium on new transmission, thus
delaying the CSC’s one-year statutory deadline for
review. The law also established a working group to
evaluate alternatives to the proposed transmission line.
Meanwhile, ISO-New England, which oversees the
regional power system, continued to identify southwest
Connecticut as having the most serious reliability
issues in New England. After evaluating 14 hybrid
designs, in September 2003 the CSC issued its final
approval of NU’s configuration that had the transmis-
sion line alternating between overhead and under-
ground (on both the 115-kV and 345-kV circuits).
Norwalk, one of four towns impacted by the project,
filed an appeal in November 2003, effectively delay-
ing the project until August 2004, when the appeal
was dismissed.
History
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NU’s B-N projectstrengthens thereliability of thepower gridin New England.
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The innovative project achieves the following:
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Project Benefits
Bethel-Norwalk Project Impact onan Average Bill for a CL&P Customer
$0.69/month
$2.14/month
$1.45/month
Cost of the Bethel-Norwalk Project
EstimatedCongestion Savings Net Savings
Completing B-N is an impor-
tant step toward solving one of the most critical
electrical grid bottlenecks and threats to electric
reliability in Connecticut, New England and the
country. B-N was needed because of southwest
Connecticut’s isolation from New England’s 345-kV
electric transmission grid.
■ Improves reliability by providing a new path for bulk power
to flow into the area;
■ Increases capacity (600 megawatt [MW], emergency
1,200 MW) to a transmission-constrained area
(southwest Connecticut);
■ Reduces (by over one-third) existing transmission congestion
and related costs which currently exceed $300 million/year;
■ Provides greater access to competitively priced generation; and
■ Demonstrates NU’s ability to execute.
The B-N project was recently honored by “Utility Automation &Engineering T&D” Magazine as its 2006 Project of the Year for B-N’scomplex construction and disciplined project-management approach.
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Project Complexity
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From the outset, the B-N
project was fraught with challenges, in terms of both
local opposition and siting complications.
Local Opposition Before B-N was announced in the
summer of 2001, residents in the four project towns
had been organized to oppose the expansion of a
congested state road and the siting of a new power
plant. Weeks after the project was announced, two
grassroots organizations started up to oppose the
plan. Their opposition was very vocal and highly
visible. But the project managers and director forged
effective working relationships among the grassroots
organizations, the municipal leaders and the company.
Issues stemming from construction were hammered
out through these relationships.
Siting Complications The Connecticut Siting Council
(CSC) application process, which requires a decision
12 months from the date an application is filed, was
prolonged by six months — opening the process more
for opponents. NU's application proposed a preferred
route and alternate, but the CSC requested seven more,
totaling 21 variations using overhead/underground
combinations. The outcome of the Siting Council
process resulted in a far more complex project
because of the "porpoising" design. The CSC finally
approved a hybrid variation using two different
underground cable technologies at two different
voltage levels and gas-insulated substations. The
route traverses developed areas, historic districts and
schools in four towns — including curvy rural roads
with solid rock under the pavement that required a
special machine to cut through the rock.
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Bethel-Norwalk
The illustration aboveprovides an outline ofthe route and the 345-kV and 115-kV overheadand underground linework completed withineach segment of the route.After a 36-month sitingprocess, NU completed allunderground and overheadconstruction in just 16 months.
The new 345-kV line includes 8.5
miles of new overhead construction and 11.8 miles of
345-kV underground cables. NU used 345-kV high-
pressure fluid-filled (HPFF) cable systems for the
majority of the underground portion of the route of
the new 345-kV line, and 2.1 miles of 345-kV cross-
linked polyethylene (XLPE) cables.
At Plumtree Substation in Bethel, NU constructed a
state-of-the-art 345-kV outdoor gas-insulated substa-
tion (GIS), required because the space for expansion
was severely constrained by adjacent wetlands.
At Norwalk Substation, NU installed:
■ an indoor 345-kV GIS system;
■ autotransformers;
■ three underground 115-kV line sections;
■ a fourth 115-kV switchyard bay; and
■ a 345-kV line terminal structure.
In addition, 345-kV line transition stations were
constructed in the towns of Bethel, Redding and
Wilton, at points where the 345-kV line transitions
from overhead to underground construction.
Project Details
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The B-N project usesthe longest length of345-kV solid dialectricunderground cable inAmerica, making NU aleader in this new, moreefficient technology.
NU’s project team was led by Project
Director Laurie Aylsworth. To limit financial risk while
maximizing control, NU leveraged experienced internal
personnel with consultants and contractors for the
tasks that required special expertise or large teams.
NU Transmission engineering staff completed the engi-
neering and design for both the substations. POWER
Engineers, Inc. engineered and designed all line compo-
nents between the two substations as well as managed
the construction. Other contracts issued included:
■ Mitsubishi Electric, LTD – GIS equipment at two substations
■ McPhee Electric Ltd., LLC – Substation civil and electrical,
transition stations electrical
■ Siemens – Furnished and installed three reactors
■ W. A. Chester – Furnished and installed 10 miles of 345-kV
HPFF underground cable
■ Kiewit Construction – Furnished and installed 10 miles of
115-kV XLPE underground cable
■ New River Electrical Corporation – Furnished and installed
2.1 miles of 345-kV XLPE underground cable
■ M.J. Electric – Constructed 345-kV overhead line
■ Blakeslee Arpaia Chapman – Transition stations civil,
345-kV XLPE civil
■ Sertex – Furnished and installed fiber optic cable system
Project Team
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The B-N project required therare skill of high-pressurefluid-filled (HPFF) cablesplicing. By some accountsthere are only 50 people inthe world with the skills andexperience to join bundlesof 345-kV HPFF cablestogether and have that jointreliably hold for the life ofthe cables.
Community Connections
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Throughout the B-N
project, the NU team demonstrated a strong commit-
ment to the communities involved, with frequent
communication to property owners, municipal officials
and state regulatory agencies. From project information
kiosks located in town halls, to maps and traffic
updates on Web sites, to newspaper articles and
advertising, key stakeholders were kept informed and
engaged throughout the entire process.
This extensive communication was begun in response
to community opposition that started up early in the
project. Just weeks after the project was announced,
two grassroots organizations were formed to oppose
the plan as residents filled high school auditoriums in
Redding, Bethel and Wilton to voice opposition. As the
project progressed, the project managers and director
established effective working relationships with the
municipal leaders.
In another instance where the NU team demonstrated
a strong commitment to our communities to ensure the
safety of schoolchildren around the construction site,
the contractor hired a chaperone to escort each student
to and from a special bus they rented to move safely
around big equipment and trenches. That’s an example
of how we care for our customers — and how we
always place safety first.
The B-N safety and environmental record was
excellent, thanks to the teamwork of hundreds of
employees and contractors who made safety and
concern for the environment their top priorities.
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By balancing the needs of the local
community with the energy requirements of the state
at large, NU has built the right solution at the right
time to strengthen Connecticut’s energy grid, ahead of
schedule and under budget.
The complex construction project — installing over
530,000 feet of new underground transmission cable,
in addition to two new 345-kV GIS substations, three
transition stations and over 20 miles of new 345-kV
line — begins to solve the critical need to reinforce
the state’s electrical infrastructure.
The B-N project improves system reliability and
provides our customers in southwest Connecticut with
greater access to competitively priced power. By
relieving system bottlenecks and improving delivery of
electricity into southwest Connecticut, we expect the
new B-N line to save customers nearly $100 million
annually. It also lends credibility to all of NU’s other
transmission projects, and positions us as one of the
foremost authorities on new transmission construction
in the country.
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Summary
TransmissionGroup
Net Income($ in millions)
Along rights-of-way, NU uses themost advanced land and vegetationmanagement practices available.We continually monitor our perform-ance and look for new ways todeliver electricity in harmony withthe environment.
HP407500