STATE OF VERMONT
PUBLIC SERVICE BOARD
Petition of Vermont Transco, LLC, and
Vermont Electric Power Company, Inc.
(collectively, “VELCO”), and Central Vermont
Public Service Corporation (“CVPS”) for a
Certificate of Public Good, pursuant to 30
V.S.A. § 248, for the “Southern Loop Project,”
located in Vernon, Guilford, Brattleboro,
Dummerston, Newfane, Brookline, Townshend,
Grafton, Windham, Andover, Chester, Ludlow
and Cavendish, Vermont, consisting of the
following elements: (1) a new, approximately
51-mile, 345 kV transmission line between
Vernon-Cavendish, to be built parallel to and
within the same utility right-of-way as
VELCO’s existing Vernon-Cavendish 345 kV
line; (2) a new VELCO 345/115 kV Vernon
substation, to be located just north of the
Vermont Yankee Nuclear Power Station; (3) a
new 345/115/46 kV Newfane substation; (4) a
new, approximately one-mile, 345 kV
transmission line loop between the new
Newfane substation and the new VernonCavendish 345 kV line; (5) expansion of
VELCO’s Coolidge substation in Cavendish,
Vermont; and (6) the implementing of
incremental energy efficiency to defer
transmission upgrades in Southern Vermont
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Docket No. ____
PREFILED TESTIMONY OF
MICHAEL BARRETT
ON BEHALF OF
PETITIONERS
November 8, 2007
The purpose of Mr. Barrett’s testimony is to describe the proposed substation upgrade
design plans associated with the Southern Loop Project.
TABLE OF CONTENTS
1.
Introduction ................................................................................................ 1
2.
Design of the Vernon Substation ............................................................... 3
3.
Design of the Newfane Substation ............................................................. 9
4.
Design of the Previously Considered West Dummerston Substation ...... 11
5.
Design of the Coolidge Substation ........................................................... 14
6.
Design Considerations to Accommodate Construction ............................ 17
7.
Conclusion ............................................................................................... 19
EXHIBITS
Exhibit Petitioners MB-1
Resume of Michael Barrett
Exhibit Petitioners MB-2
Vernon Substation Aerial Photograph with General
Arrangement(1 sheet – sheet 286)
Exhibit Petitioners MB-3
Vernon Substation Detailed General Arrangement
Site Plan (1 sheet, sheet 286-6000D)
Exhibit Petitioners MB-4
Vernon Substation General Arrangement Elevations
(6 sheets 286-6020D – 6025D)
Exhibit Petitioners MB-5
Vernon Substation One-Line Diagram
(2 sheets, sheets 286-OL-0001F – 0002F)
Exhibit Petitioners MB-6
Vernon Substation Site Grading Plan
(to be provided)
Exhibit Petitioners MB-7
Newfane Substation Aerial Photograph with
General Arrangement
(1 sheet, sheet 287A)
Exhibit Petitioners MB-8
Newfane Substation Detailed General Arrangement
Site Plan
(1 sheet, sheet 287A-6000D)
Exhibit Petitioners MB-9
Newfane Substation General Arrangement
Elevations
(4 sheets, sheets 287A-6020D – 6023D)
Exhibit Petitioners MB-10
Newfane Substation One-Line Diagram
(2 sheets, sheets 287A-OL-0001F – 0002F)
Exhibit Petitioners MB-11
Newfane Substation Site Grading Plan
(1 sheet, sheet 287A-6100D)
Exhibit Petitioners MB-12
Coolidge Substation Aerial Photograph with
General Arrangement
(1 sheet, sheet 216)
Exhibit Petitioners MB-13
Coolidge Substation Detailed General Arrangement
Site Plan
(2 sheets, sheets 216-6000D – 6001D)
Exhibit Petitioners MB-14
Coolidge Substation General Arrangement
Elevations
(6 sheets, sheets 216-6024D – 6029D)
Exhibit Petitioners MB-15
Coolidge Substation One-Line Diagrams
(3 sheets, Pre & Post Project sheets 216-OL-0001F
– 216-OL0002F)
Exhibit Petitioners MB-16
Coolidge Substation Site Grading Plan
(one sheet, sheet 216-6100D)
Exhibit Petitioners MB-17
West Dummerston Substation Aerial Photograph
with General Arrangement
(1 sheet, sheet 287)
Exhibit Petitioners MB-18
West Dummerston Substation Detailed General
Arrangement Site Plan
(1 sheet, sheet 287-6000D)
Exhibit Petitioners MB-19
West Dummerston Substation General Arrangement
Elevations
(4 sheets, sheets 287-6020D – 6023D)
Exhibit Petitioners MB-20
West Dummerston Substation One-Line Diagram
(2 sheets, sheets 287-0L-0001F – 287-0L-0002F)
Exhibit Petitioners MB-21
West Dummerston Substation Site Grading Plan
(1 sheet, sheet 287-6100D)
Exhibit Petitioners MB-22
Substation Lighting Cut Sheets
Exhibit Petitioners MB-23
Typical Oil Containment
STATE OF VERMONT
PUBLIC SERVICE BOARD
Petition of Vermont Transco, LLC, and
Vermont Electric Power Company, Inc.
(collectively, “VELCO”), and Central Vermont
Public Service Corporation (“CVPS”) for a
Certificate of Public Good, pursuant to 30
V.S.A. § 248, for the “Southern Loop Project,”
located in Vernon, Guilford, Brattleboro,
Dummerston, Newfane, Brookline, Townshend,
Grafton, Windham, Andover, Chester, Ludlow
and Cavendish, Vermont, consisting of the
following elements: (1) a new, approximately
51-mile, 345 kV transmission line between
Vernon-Cavendish, to be built parallel to and
within the same utility right-of-way as
VELCO’s existing Vernon-Cavendish 345 kV
line; (2) a new VELCO 345/115 kV Vernon
substation, to be located just north of the
Vermont Yankee Nuclear Power Station; (3) a
new 345/115/46 kV Newfane substation; (4) a
new, approximately one-mile, 345 kV
transmission line loop between the new
Newfane substation and the new VernonCavendish 345 kV line; (5) expansion of
VELCO’s Coolidge substation in Cavendish,
Vermont; and (6) the implementing of
incremental energy efficiency to defer
transmission upgrades in Southern Vermont
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PREFILED TESTIMONY OF
MICHAEL BARRETT
ON BEHALF OF
PETITIONERS
1
2
1.
Q1.
Introduction
Please state your name and business address.
Docket No. ____
Southern Loop Project, PSB Docket No. ____
Prefiled Testimony of Michael Barrett
November 8, 2007
Page 2 of 19
1
A1.
2
My name is Michael Barrett. My business address is PLM Inc. (“PLM”), 35
Main Street, Hopkinton, Massachusetts 01748.
3
4
Q2.
By whom are you employed and in what position?
5
A2.
I am a Principal Engineer for PLM. I have been contracted by Vermont Electric
6
Power Company, Inc. (“VELCO”) to perform the duties and responsibilities as
7
the Owners Engineer for the Southern Loop Project (“Project”). I have served in
8
that position since November of 2006. My resume is attached as Exhibit
9
Petitioners MB-1.
10
11
Q3.
Please describe your educational background and work experience.
12
A3.
I received my Bachelor of Science degree in Electrical Engineering from
13
Northeastern University in 1987. I was employed as an electrical engineer at New
14
England Electric System after graduation until 1991. I have been employed at
15
PLM since 1991. My work responsibilities include overall responsibility for the
16
technical design of major substation and transmission facilities, and are further
17
detailed in my resume.
18
19
Q4.
What is the purpose of your testimony?
20
A4.
My testimony will address the development of the design for the proposed
21
345/115 kV Vernon substation, proposed to be located on Entergy’s property just
22
north of the Vermont Yankee Nuclear Power Plant; the proposed 345/115 kV
Southern Loop Project, PSB Docket No. ____
Prefiled Testimony of Michael Barrett
November 8, 2007
Page 3 of 19
1
VELCO Newfane substation and associated 46 kV CVPS Newfane substation; the
2
previously considered West Dummerston substation and associated 46 kV CVPS
3
West Dummerston substation; and expansion of VELCO’s Coolidge substation in
4
Cavendish, Vermont.
5
6
2.
Design of the Vernon Substation
7
Q5.
Please describe the existing Vermont Yankee substation.
8
A5.
The existing Vermont Yankee substation, owned by Entergy Nuclear Vermont
Yankee (“Entergy”), consists of two switchyards located adjacent to the Vermont
9
10
Yankee Nuclear Power Plant in Vernon, Vermont. The 345 kV switchyard
11
contains a five breaker 345 kV ring bus with one generator position, three line
12
positions and one transformer position. The transformer position supplies a
13
345/115 kV power transformer that connects to the adjacent 115 kV switchyard.
14
The 115 kV switchyard contains a 115 kV radial bus with one transformer
15
position, one line position, one position that feeds the Vermont Yankee startup
16
transformers, and three 115 kV capacitor banks. The location of the existing
17
substation is depicted on Exhibit Petitioners MB-2.
18
19
Q6.
Please describe the proposed Vernon Substation.
20
A6.
VELCO proposes to build the new Vernon substation in a vacant fenced-in lot
21
located on Entergy’s property, just to the north of the existing Vermont Yankee
22
substation yard. The location of the site is depicted on Exhibit Petitioners MB-2,
Southern Loop Project, PSB Docket No. ____
Prefiled Testimony of Michael Barrett
November 8, 2007
Page 4 of 19
1
which is an aerial photograph of the premises with the existing and proposed
2
substation site plans overlaid. The proposed new Vernon substation will consist
3
of a new 345 kV substation, two 345/115 kV power transformers, and a new 115
4
kV substation. The detailed general arrangement, elevation drawings, one-line
5
drawings, and grading plans are included as Exhibit Petitioners MB-3, MB-4,
6
MB-5 and MB-6.
7
8
The 345 kV substation will be designed as a four-bay, breaker and one half
9
configuration bus, with four line positions, two transformer positions, one
10
generator position, and one future position. The 345 kV substation will initially
11
contain eleven circuit breakers with associated structural steel, disconnect
12
switches, bus work and auxiliary equipment. Space has been allocated for a
13
future twelfth circuit breaker and third 345/115 kV power transformer. In
14
addition, space in the yard has been reserved for two additional 345 kV bays.
15
16
The 115 kV substation will be designed as a two-bay, breaker and one half
17
configuration bus, with two line positions and two transformer positions. The 115
18
kV substation will initially contain six circuit breakers with associated structural
19
steel, disconnect switches, bus work and auxiliary equipment. The existing
20
capacitor banks will be relocated from the Vermont Yankee 115 kV switchyard to
21
connect to the buses in the new Vernon substation. In addition, space in the yard
22
has been reserved for two additional 115 kV bays.
Southern Loop Project, PSB Docket No. ____
Prefiled Testimony of Michael Barrett
November 8, 2007
Page 5 of 19
1
The substation yard will be approximately 13 acres, and will be surrounded by a
2
chain link fence. A new control house will be installed to contain the protection
3
and control equipment for the new substation.
4
5
Q7.
6
7
Please describe the basis for the switchyard layout of this substation, and any
design considerations utilized to maintain service during construction.
A7.
The new Vernon substation will be located at the northern end of Entergy’s
8
property, on a currently vacant field. The existing 345 kV and 115 kV lines
9
connected to the Vermont Yankee switchyard traverse this site, and obstruct
10
construction. Outages to these lines have an impact both on the supply to
11
Vermont loads and on the Vermont Yankee plant operation. Therefore, in order
12
to accomplish construction and minimize outages, we developed the following
13
site layout and construction/cutover sequence for the Vernon substation.
14
15
The 115 kV switchyard will require temporary outage of the K-186 line (115 kV
16
Vermont Yankee to Chestnut Hill) during construction. This line will be
17
relocated east of its existing alignment for the first two spans north of the existing
18
switchyard, all within the existing Vermont Yankee Nuclear Power Station fence,
19
to provide space for the new 115 kV switchyard construction, as shown on the
20
Detailed General Arrangement Plan, Exhibit Petitioners MB-3. This will mean
21
that VELCO will install temporary 115 kV structures within this Vermont Yankee
Southern Loop Project, PSB Docket No. ____
Prefiled Testimony of Michael Barrett
November 8, 2007
Page 6 of 19
1
Nuclear Power Station fence during construction. These will be removed
2
following construction.
3
4
The 345 kV switchyard is designed to be constructed in two phases. There is
5
room on the site to construct the two western bays of the switchyard (up to the
6
center maintenance bay) while all lines remain in service. Following construction
7
of the two western bays, the existing 340 (345 kV Vermont Yankee to Coolidge)
8
and 379 (345 kV Vermont Yankee to Amherst) lines will be temporarily
9
terminated in these bays, through the bus tie breakers which will be locked closed.
10
Once the overhead portions of these two lines are removed, the two eastern bays
11
of the 345 kV switchyard will be constructed. Following completion of the 345
12
kV switchyard, the 381 (345 kV Vermont Yankee to Northfield) line will be
13
relocated to the new switchyard, and the first 345/115 kV power transformer
14
installed to energize the 115 kV yard. At this time, the remaining lines will be
15
moved to their final positions and the new switchyards fully commissioned.
16
Several temporary 345 kV structures, within the existing Vermont Yankee
17
Nuclear Power Station fence, will likely be required to facilitate the construction
18
process and minimize impact to Vermont Yankee operation. These will be
19
removed following construction. These final steps will likely require a Vermont
20
Yankee shutdown, and VELCO will coordinate that work with Entergy.
21
Southern Loop Project, PSB Docket No. ____
Prefiled Testimony of Michael Barrett
November 8, 2007
Page 7 of 19
1
Q8.
What design standards were used to design the new substation?
2
A8.
VELCO’s Substation Design Standards were followed in the design of the new
3
substation. VELCO’s Substation Design Standards are based on industry
4
standards, including the National Electrical Safety Code (NESC), Institute of
5
Electrical and Electronic Engineers (IEEE), American National Standards
6
Institute (ANSI) and National Electrical Manufacturer’s Association (NEMA).
7
8
Q9
Please describe the substation lighting plans.
9
A9.
VELCO will install its standard lighting plans at this substation and the other
10
Southern Loop substations. These plans are consistent with the lighting plans
11
approved by the Public Service Board for substation lighting in Docket No. 6860.
12
Specifically, under normal circumstances, only limited night-time lighting would
13
be on at the substation, at the entrance and at the control building, and along the
14
substation fence. The fence lights will be 70-watt Metal Halide floodlights or
15
luminaries, angled slightly downwards. The exterior mounted control building
16
lights will be 50-watt Metal Halide cutoff fixtures. One light by the gate and one
17
light on the control house will be switched by a photo cell.
18
19
If nightime maintenance or emergency work is required, VELCO will bring in
20
portable light towers to perform the work. The location of planned lighting
21
installations are shown in the Detailed General Arrangement Plans, Exhibit
Southern Loop Project, PSB Docket No. ____
Prefiled Testimony of Michael Barrett
November 8, 2007
Page 8 of 19
1
Petitioners MB-3. Cut Sheets with lighting specifications are included as Exhibit
2
Petitioners MB- 22.
3
4
Q10.
Please describe the oil containment plans for the substation transformers.
5
A10.
To minimize the potential for oil contamination, the new transformers will be
6
installed on concrete foundations with integral oil retention provisions sufficient
7
to contain the total transformer oil volume. The foundation and oil retention
8
system will be designed in accordance with ANSI/IEEE Standard 980, “IEEE
9
Guide for Containment and Control of Oil Spills in Substations.” This meets
10
VELCO’s current standard practice for environmental protection and VELCO’s
11
Spill Prevention Control and Countermeasures Plan, and is in compliance with
12
applicable federal regulations.
13
14
A drawing detailing the typical system design is included as Exhibit Petitioners
15
MB-23. The dimensions and volumes shown on this Exhibit are generic in
16
nature, but serve to illustrate the features of the design. The containment system
17
is designed to retain all fluids that fall within the surface area of the system,
18
including rainwater/snowmelt. During periodic maintenance visits, the
19
containment is inspected for presence of oil and if clean, water is manually
20
pumped out of the containment. The containment system is designed with
21
significant volume in excess of the transformer oil volume to permit water to
22
accumulate in the containment area between maintenance visits. The final details
Southern Loop Project, PSB Docket No. ____
Prefiled Testimony of Michael Barrett
November 8, 2007
Page 9 of 19
1
of each transformer’s foundation and containment system will be designed once
2
details of the actual transformers are available.
3
4
3.
Design of the Newfane Substation
5
Q11.
Please describe the proposed VELCO Newfane substation.
6
A11.
The proposed Newfane substation will consist of a new 345 kV substation, a new
7
345/115 kV power transformer, a new 115 kV substation, and a new 115/46 kV
8
power transformer. The location of the site is depicted on Exhibit Petitioners
9
MB-7, which is an aerial photograph of the premises with the substation site plan
10
overlaid. The detailed general arrangement, elevation drawings, one-line
11
drawings, and grading plans are included as Exhibit Petitioners MB-8, MB-9,
12
MB-10 and MB-11.
13
14
The 345 kV substation will be designed as a four position ring bus, with two line
15
positions and two transformer positions. Initially, two line positions and one
16
transformer position will be constructed. The 345 kV substation will initially
17
contain three circuit breakers with associated structural steel, disconnect switches,
18
bus work and auxiliary equipment. Space has been allocated for a future fourth
19
circuit breaker and 345/115 kV power transformer.
20
21
The 115 kV substation will be designed as a four position ring bus. Initially, a
22
small portion of this substation will be constructed to provide a path from the
Southern Loop Project, PSB Docket No. ____
Prefiled Testimony of Michael Barrett
November 8, 2007
Page 10 of 19
1
secondary of the 345/115 kV power transformer to the primary of the 115/46 kV
2
power transformer. The 115 kV substation will initially contain one 115 kV
3
circuit breaker with associated structural steel, disconnect switches, bus work and
4
auxiliary equipment. Space has been allocated for two future 115 kV positions,
5
including three future 115 kV circuit breakers and associated structural steel,
6
disconnect switches, bus work and auxiliary equipment. The substation yard will
7
be approximately 8 acres, and will be surrounded by a chain link fence. A new
8
control house will be installed to contain the protection and control equipment for
9
the new substation.
10
11
Q12.
Please describe the proposed CVPS Newfane substation.
12
A12.
This is discussed in the prefiled testimony of Ryan Johnson.
14
Q13.
What design standards were used to design the new VELCO substation?
15
A13.
VELCO’s Substation Design Standards were followed in the design of the new
13
16
VELCO substation. Please refer to A8 of my testimony above for a description.
17
18
Q14.
Please describe the substation lighting plans.
19
A14.
VELCO will install its standard lighting plans at this substation and the other
20
Southern Loop substations. Please refer to A9 of my testimony above for a
21
description.
22
Southern Loop Project, PSB Docket No. ____
Prefiled Testimony of Michael Barrett
November 8, 2007
Page 11 of 19
1
Q15
Please describe the oil containment plans for the VELCO substation transformers.
2
A15.
VELCO’s standard oil containment design will be utilized at this substation.
3
Please refer to A10 of my testimony above for a description.
4
5
4.
Design of the Previously Considered West Dummerston Substation
6
Q16.
Please describe CVPS’s existing West Dummerston substation.
7
A16.
The existing West Dummerston substation is located on the east side of Highway
8
30 in Dummerston, Vermont, adjacent to the West River. The existing substation
9
consists of a small fenced-in yard containing a 46 kV switching structure, a 46
10
12.47 kV power transformer, and a 12.47 switching structure that supplies a
11
single 12.47 kV distribution feeder.
12
13
Q17.
Please describe the initially proposed VELCO West Dummerston substation.
14
A17.
The proposed West Dummerston substation consisted of a new 345 kV substation,
15
a new 345/115 kV power transformer, a new 115 kV substation, a new 115/46 kV
16
power transformer, and a new 46 kV substation. The location of the initially
17
proposed site is depicted on Exhibit Petitioners MB-17, which is an aerial
18
photograph of the premises with the substation site plan overlaid. The detailed
19
general arrangement, elevation drawings, one-line drawings, and grading plans
20
are included as Exhibit Petitioners MB-18, MB-19, MB-20 and MB-21.
21
Southern Loop Project, PSB Docket No. ____
Prefiled Testimony of Michael Barrett
November 8, 2007
Page 12 of 19
1
The 345 kV substation was designed as a four position ring bus, with two line
2
positions and two transformer positions. Initially, two line positions and one
3
transformer position were to be constructed. The 345 kV substation was to
4
initially contain three circuit breakers with associated structural steel, disconnect
5
switches, bus work and auxiliary equipment. Space had been allocated for a
6
future fourth circuit breaker and 345/115 kV power transformer.
7
8
The 115 kV substation was designed as a four position ring bus. Initially, a small
9
portion of this substation was to be constructed to provide a path from the
10
secondary of the 345/115 kV power transformer to the primary of the 115/46 kV
11
power transformer. The 115 kV substation was to initially contain one 115 kV
12
circuit breaker with associated structural steel, disconnect switches, bus work and
13
auxiliary equipment. Space had been allocated for two future 115 kV positions,
14
including three future 115 kV circuit breakers and associated structural steel,
15
disconnect switches, bus work and auxiliary equipment.
16
17
Q18.
18
19
Please describe the initially proposed CVPS West Dummerston substation
expansion.
A18.
The 46 kV substation was designed as a single main bus switching station with a
20
transfer bus. The transfer bus would have allowed for maintenance of any circuit
21
breaker without a circuit outage. Initially, three line positions and one
22
transformer position were to be constructed. The 46 kV substation was to initially
Southern Loop Project, PSB Docket No. ____
Prefiled Testimony of Michael Barrett
November 8, 2007
Page 13 of 19
1
contain five 46 kV circuit breakers with associated structural steel, disconnect
2
switches, bus work and auxiliary equipment.
3
4
Q19.
5
6
Please describe the basis for the switchyard layout of these substations, and any
design considerations utilized to maintain service during construction.
A19.
This site presently contains a CVPS 46 12.47 distribution substation, and is
7
traversed by CVPS 46 kV and 12.47 kV lines. These must have remained in
8
service during construction to support area loads. The existing 46 kV and 12.47
9
kV lines were to be relocated out of the way of construction, as shown on the
10
Detailed General Arrangement Plans, Exhibit Petitioners MB-18. The proposed
11
substation layout would have allowed the existing 46 12.47 kV substation to
12
remain in service during construction.
13
14
Q20.
What design standards were used to design the initially proposed new substation?
15
A20.
VELCO’s Substation Design Standards were followed in the design of the
16
initially proposed new substation. Please refer to A8 of my testimony above for a
17
description.
18
19
Q21.
Please describe the substation lighting plans.
20
A21.
VELCO would have installed its standard lighting plans at this substation and the
21
other Southern Loop substations. Please refer to A9 of my testimony above for a
22
description.
Southern Loop Project, PSB Docket No. ____
Prefiled Testimony of Michael Barrett
November 8, 2007
Page 14 of 19
1
Q22.
Please describe the oil containment plans for the substation transformers.
2
A22.
VELCO’s standard oil containment design would have been utilized at this
3
substation. Please refer to A10 of my testimony above for a description.
4
5
5.
Design of the Coolidge Substation
6
Q23.
Please describe VELCO’s existing Coolidge substation.
7
A23.
The existing Coolidge substation is located off of Quent Phalen Road in the Town
8
of Cavendish, Vermont, and consists of a three position 345 kV ring bus, a
9
345/115 kV power transformer, a six position 115 kV ring bus, and two 115 kV
10
capacitor banks.
11
12
Q24.
Please describe the proposed Coolidge substation expansion.
13
A24.
The proposed Coolidge substation will be expanded to include a three-bay 345 kV
14
substation with a breaker and one half configuration, a six position 115 kV ring
15
bus, and four 115 kV capacitor banks. The location of the site is depicted on
16
Exhibit Petitioners MB-12, which is an aerial photograph of the premises with the
17
substation site plan overlaid . The detailed general arrangement elevation
18
drawings, one-line drawings, and grading plans are included as Exhibit Petitioners
19
MB-13, MB-14, MB-15 and MB-16.
20
21
The existing 345 kV switchyard will be expanded into a three-bay breaker and
22
one half configuration. The north bus will be relocated approximately 30 feet to
Southern Loop Project, PSB Docket No. ____
Prefiled Testimony of Michael Barrett
November 8, 2007
Page 15 of 19
1
the north and the north fence will be relocated approximately 10 feet to the north.
2
In addition, the west fence will be relocated approximately 10 feet to the west to
3
provide sufficient space for the new equipment. Please refer to Exhibit
4
Petitioners MB-12. A total of five new 345 kV circuit breakers with associated
5
structural steel, disconnect switches, bus work and auxiliary equipment will be
6
installed. The new substation will terminate three (3) 345 kV lines (existing lines
7
No. 340 (345 kV Coolidge to Vernon) and No. 350 (345 kV Coolidge to West
8
Rutland), planned line No. 360 (second 345kV Coolidge to Vernon) and two
9
power transformers (one existing and one future).
10
11
The 115 kV substation will be expanded approximately 55 feet to the east to
12
provide space for two new 115 kV capacitor banks with associated circuit
13
breakers, disconnects and bus work. Please refer to Exhibit Petitioners MB-12.
14
In addition, all six of the existing 115 kV circuit breakers, along with their
15
associated disconnect switches and taps, will be replaced. The existing thermal
16
ratings of these devices are not adequate for the 115 kV power flows under certain
17
contingencies. Finally, a portion of the 115 kV switchyard will be expanded
18
approximately 130 feet to the north to accommodate a future 345/115 kV power
19
transformer. The existing control house is large enough to accommodate the
20
protection and control equipment associated with the expanded substation.
21
Southern Loop Project, PSB Docket No. ____
Prefiled Testimony of Michael Barrett
November 8, 2007
Page 16 of 19
1
Q25.
2
3
Please describe the basis for the switchyard layout of this substation, and any
design considerations utilized to maintain service during construction.
A25.
There were several items to consider with the proposed layout of Coolidge
4
substation. Coolidge is an existing, operating substation that serves as both a
5
critical point in the 345 kV system feeding north into Vermont, and as an
6
important stepdown facility to reinforce the southern Vermont 115 kV system. It
7
is necessary to maintain this facility in service for as much of the time as possible.
8
The existing 345 kV bus was constructed as a ring bus, and is being expanded into
9
a breaker and one half configuration. For substations of this size, the current ISO-
10
NE guidelines call for a breaker and one half configuration. Further, site
11
constraints preclude expansion of the existing ring bus to provide the desired
12
number of positions. The existing substation is not wide enough, in the
13
north/south direction, to accommodate the three breakers across a bay, so the
14
existing north bus will be relocated to the north to provide sufficient space.
15
The proposed 345 kV configuration allows the equipment at the southern end of
16
the yard to remain in place. The major supply line presently is the existing 345
17
kV line from Vermont Yankee to Coolidge (the “340 line”). The proposed design
18
allows for a path from the 340 line to both the 345/115 kV transformer and the
19
existing 345 kV line between the Coolidge and West Rutland substations (the
20
“350 line”). It will not be necessary to remove both the 350 line and the
21
transformer from service simultaneously. Also, the new Vernon to Coolidge
22
345kV line that is proposed as part of the Southern Loop Project upgrades (the
Southern Loop Project, PSB Docket No. ____
Prefiled Testimony of Michael Barrett
November 8, 2007
Page 17 of 19
1
“360 line”) will terminate in a new bay position adjacent to the 340 line. This
2
will allow the 340 line to remain in service until the 360 line is energized.
3
4
Q26.
What design standards were used to design the new substation?
5
A26.
VELCO’s Substation Design Standards were followed in the design of the new
6
substation. Please refer to A8 of my testimony above for a description.
7
8
Q27.
Please describe the substation lighting plans.
9
A27.
VELCO will install its standard lighting plans at this substation and the other
10
Southern Loop substations. Please refer to A9 of my testimony above for a
11
description.
12
13
14
6.
Q28.
15
16
Design Considerations to Accommodate Construction
Describe the proposed construction sequence for the substations and explain how
it will minimize outages.
A28.
The substation construction sequence and the line construction sequence must be
17
integrated, as portions of the substation work depend on availability of the
18
transmission line segments. Also, the final construction sequence can not be
19
determined until the actual construction schedule is known. The construction
20
sequence is very dependant on seasonal factors such as Vermont loads and other
21
transmission outages. In addition, the Vermont Yankee refueling schedule will
22
have an impact since it is desired to perform a portion of the Vernon Substation
Southern Loop Project, PSB Docket No. ____
Prefiled Testimony of Michael Barrett
November 8, 2007
Page 18 of 19
1
work during the refueling outage if possible to mitigate the economic costs of
2
plant outages.
3
4
In concept, the proposed Project would be constructed as follows (with much of
5
the work happening in parallel):
6
-
Vernon Substation
7
-
Newfane Substation
8
-
new 360 line from Vernon to Newfane to Coolidge
9
-
Coolidge Substation (energized in stages)
10
11
One key driver to the sequence is to maintain a north/south 345 kV path during
12
construction. This requires that the new 360 line be placed in service prior to
13
major work on the existing 340 line. Thus, the Vernon substation must be
14
completed and cut over first to provide a source at the southern end of the 360
15
line. The second driver is to maintain Vermont Yankee in service as much as
16
possible during construction. The construction of Vernon substation will require
17
Vermont Yankee to reduce generation (and shut down for some work in the 345
18
kV yard). We will attempt to schedule this work during refueling outages, to the
19
extent practical.
20
21
We anticipate that the 115 kV yard at Vernon, the west half of the 345 kV yard at
22
Vernon, Newfane substation, and the majority of the 345 kV work at Coolidge
Southern Loop Project, PSB Docket No. ____
Prefiled Testimony of Michael Barrett
November 8, 2007
Page 19 of 19
1
would be constructed at the same time that the new 360 line is being constructed.
2
The temporary cutover of the 340 and 379 lines at Vernon would be completed,
3
followed by removal of the existing 340 and 379 lines within the site and
4
completion of the east half of the Vernon 345 kV yard. Following completion of
5
the remaining Vernon 345 kV yard, the new 345 kV substation would be
6
commissioned and the lines moved to their final positions. This now provides a
7
position for the new 360 line. Following energization of the new 360 line, the
8
340 terminal upgrades would be completed at Coolidge.
9
10
11
7.
Q29.
12
13
Conclusion
In your opinion, have the substations included in the Southern Loop Project, as
described in the exhibits you have sponsored, reached a design level of detail?
A29.
Yes; the plans and elevations that have been included as exhibits to this testimony
14
reflect the locations of the structures actually proposed for construction by the
15
Petitioners.
16
17
Q30.
Does this conclude your testimony?
18
A30.
Yes it does.