WECC Project Coordination Review
Report
Path 65 Upgrade
June 19, 2013
1.0 Introduction
This project proposes to increase the rating of the Pacific Direct Current Intertie (PDCI), Path 65,
from its present rating of 3100 MW to 3220 MW for north to south power flow. No change is
proposed for the south to north direction. This increase will be realized by increasing the
operating voltage at the northern terminal, the Celilo Converter Station, from +500 kV to + 520
kV while maintaining the present current rating of 3100 A. The voltage at the southern
terminal, the Sylmar Converter Station, will increase by approximately 20 kV, which is within
the capability of existing terminal equipment.
This report serves to document the WECC Project Coordination Process and how the project
sponsor, the Bonneville Power Administration (BPA), meets the four Project Coordination
Review Objectives.
2.0 Project Background
The Celilo Converter Station is over 40 years old and aging systems and equipment failures are
contributing to deteriorating reliability of the PDCI. Over the years, several upgrades have
added layers of new technology over old and created a highly complex four converter system
that is difficult to operate and maintain. A comprehensive BPA study of in-kind equipment
replacements required to sustain acceptable performance over the next 30 years revealed that
the present value of required investments would exceed the cost of replacing the entire
converter station with a modern two converter terminal. The complete replacement option
would be simpler to operate, substantially less costly to maintain and would reduce terminal
losses. This approach would largely mirror the 2004 Sylmar Replacement Project which
replaced the four converter terminal, including the obsolete mercury arc valves, with a modern
two converter terminal.
Installing all new converter equipment at Celilo would also provide an opportunity to upgrade
the terminal power rating for a relatively low incremental cost which could support additional
PDCI capacity. To explore this possibility, BPA and Los Angeles Department of Water and Power
(LADWP) undertook a study of PDCI upgrade alternatives. The study found that the Sylmar
converters have the inherent capacity to support up to 3800 MW (input at Celilo) for north to
south power flows. The study also examined the capability of the Celilo-Sylmar DC transmission
line and found that extensive upgrades would be required for the portion of line from the
Nevada-Oregon Border (NOB) to Sylmar which is owned by LADWP and the other Southern
Owners (Southern California Edison and the cities of Burbank, Glendale and Pasadena). The
Celilo-NOB portion of the line owned by BPA was designed with higher ground clearance and
would require less costly upgrades including insulator replacement and shunting of
compression fittings to support up to 3800 MW.
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Preliminary planning studies found that the AC transmission system supporting both Celilo and
Sylmar converters would require increasing degrees of reinforcement depending on the level of
PDCI upgrade ultimately implemented. PDCI bipole loss during heavy north to south power flow
is a severe disturbance with widespread performance impacts for the western interconnection
transmission system. Any increase in PDCI north to south transfer rating will increase the
severity of this disturbance and will be studied extensively as part of the WECC Path Rating
Process to ensure that system performance criteria are met for all PDCI outage contingencies.
While the higher rating will increase outage impacts, the Celilo Converter Station modernization
will significantly improve PDCI reliability and reduce the probability of bipole outages.
Based on the results of the PDCI alternatives study, three potential levels of upgrade were
identified:



3220 MW – This level would maintain the existing 3100 A current rating but would
increase the Celilo voltage to 520 kV. This would limit the voltage at NOB to 500 kV
thereby requiring no line upgrades south of NOB. The Celilo-NOB line portion would be
upgraded. Control modifications would be required at Sylmar. Preliminary BPA studies
indicate that no AC transmission system reinforcements will be required to support this
120 MW rating increase, beyond the existing reinforcements identified for other system
demands which also improve the service to the PDCI such as the Big Eddy-Knight 500 kV
line and the Big Eddy-John Day #1 500 kV line upgrade.
3450 MW – This level, referred to as the voltage only upgrade, would maintain the
3100 A current rating while increasing Celilo voltage to 556 kV. This would make full use
of the Sylmar converter voltage capability in inverter mode. No additional line upgrades
would be required for the Celilo-NOB line. Substantial NOB-Sylmar line modifications
would be required including insulator replacement and raising or replacing a large
number of towers to provide adequate ground clearance. Unspecified AC transmission
system reinforcements would be required to support this 350 MW rating increase.
3820 MW – This level, referred to as the voltage and current upgrade, would increase
the current rating to 3410 A, which is the maximum inherent capability of Sylmar
terminal, and increase Celilo voltage to 560 kV. No additional line upgrades would be
required for the Celilo-NOB line. Additional line upgrades would be required for the
NOB-Sylmar line to provide additional clearance for increased conductor sag. Sylmar
transformers would require additional cooling capacity. Unspecified AC transmission
system reinforcements would be required to support this 720 MW rating increase.
In December 2011, BPA Executive Management approved proceeding with the Celilo complete
replacement option with the new terminal designed to support the full 3820 MW level capable
of operating at 560 kV and 3410 A. The relatively small incremental cost increase to extend the
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Celilo converter rating and Celilo-NOB line capability beyond 3220 MW to 3820 MW would
preserve the opportunity for future upgrade of the PDCI to more fully utilize the inherent
capacity of the existing Sylmar converters. However, because of the high costs and uncertain
benefits for the Southern Owners, they are unable to support a PDCI uprating beyond the 3220
kV level at this time.
The decision to upgrade the 265 mile Celilo-NOB transmission line cannot be made before the
Environmental Assessment (EA) is completed in May 2014. If the environmental process results
in a “No Action” decision for the transmission line upgrade project, the proposal to increase the
PDCI north to south rating to 3220 MW will be withdrawn and the rating will remain at 3100
MW. The PDCI upgrade business case anticipated this possibility and analysis supported
proceeding with the Celilo upgrade project even if the PDCI rating were never increased beyond
the current 3100 MW rating. Delaying the Celilo upgrade decision until the line decision was
completed would have delayed replacement of the unreliable Celilo terminal equipment by two
or more years and exposed the PDCI to a high risk of major Celilo failures.
HVDC system manufacturers were invited to submit offers in June 2012. After competitive
evaluation of offers, a contract was awarded to ABB in December 2012. ABB will begin
construction and equipment installation in October 2014 and complete testing and
commissioning in December 2015. ABB will reuse the existing converter 1 and 2 valve hall
buildings for the new converter valves requiring an outage of converters 1 and 2 from
November 2014 through December 2015 during which time the PDCI capacity will be curtailed
to 2000 MW.
Plans for the Celilo-NOB transmission line upgrade work will not be finalized until completion of
the environmental process in May of 2014. If the decision is to proceed as proposed, the work
will begin in the summer of 2014 and be completed by November 2017. This schedule is based
on minimizing outage impacts and will involve both dead line and live line work. The schedule
may be accelerated if additional outages can be arranged during periods of low PDCI capacity
demand. Although the Celilo terminal upgrade will be completed by the end of 2015, operation
at the proposed 3220 MW rating will not be possible until the Celilo-NOB transmission line
upgrade work is completed which may be as late as November 2017.
3.0 Plan of Service
The following Plan-of-Service (POS) will be implemented to improve reliability and facilitate
uprating the PDCI to 3220 MW north to south:
Celilo Converters 1 and 2
Replace all AC and DC equipment, controls and auxiliaries to support a potential 3820
MW rating
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Celilo Converters 3 and 4
Convert to stand alone operation in October 2014
Place in cold standby in January 2016 then retire and salvage in 2017
Celilo-NOB Transmission Line
Replace insulators and vibration dampers, shunt compression fittings, upgrade access
roads and install failure containment dead-end structures by November 2017
NOB-Sylmar Transmission Line
No changes planned
Sylmar Converters
Modify controls and communications to support 3220 MW PDCI upgrade
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Pacific DC Intertie – One-Line Diagram 2013
Big Eddy 500
East
Celilo
Sylmar
NOB
West
Bay 10
Pole 4
Line 2
Bay 8
Bus 1
C2
M
Bay E5
500 kv AC
Bay 7
Bus 2
M
C2
Bay E6
C4
M
Bay 6
Line 1
LADWP 230 kv
Bank 5
Bank G
Bank E
Bank F
SCE 220 kv
M
Sect 4
Bay E9
Line 4
NC
C1
Bay E10
M
Sect 3
Bank 2
C1
230 kv AC
Sect 2
C3
M
Line 3
Pole 3
Sect 1
Big Eddy 230
M
Metering Point
Pacific DC Intertie – One-Line Diagram 2016
Big Eddy 500
East
Celilo
Sylmar
NOB
West
Bay 10
Pole 4
Line 2
C2
M
Bay 8
Bay E5
500 kv AC
Bay 7
M
Future
C2
Bay E6
M
Bay 6
Line 1
LADWP 230 kv
Bank 5
SCE 220 kv
Bay E9
Sect 4
NC
C1
Bay E10
M
Sect 3
C1
Bank 2
Sect 2
Sect 1
Big Eddy 230
PDCI Upgrade Project Coordination Report
Pole 3
M
Metering Point
5
4.0 Project Coordination Review Objectives
This section of the report provides responses to each of the Project Coordination Review
Objectives.
4.1 Undertake Integrated Project Evaluation
“Take multiple project needs and plans into account, including identified utilities’ and
non-utilities’ future needs, environmental and other stakeholder interests.
The findings of the TEPPC, SPG, or other analyses reports may be used to satisfy these
requirements;
Identify transmission physical and operational constraints resulting from the project or
that are removed by the project;
Look beyond specific end points of the sponsors’ project to identify broader regional and
sub-regional needs or opportunities;”
The deteriorating reliability of aging Celilo terminal equipment and controls has caused
numerous outages and capacity constraints on the PDCI over the last 10 years. This
project has been driven primarily by the need to remedy this poor performance and
assure long term reliability. The reduction of operating constraints plus the increased
rating provided by this project will increase the available PDCI capacity.
The following excerpt from the WECC 10-Year Regional Transmission Plan dated
September 22, 2011 suggests region wide benefits may result from PDCI capacity
upgrade:
“The utilization of and congestion on the Pacific DC Intertie (Path 65) and
California-Oregon Intertie (Path 66) continue to increase under most conditions
analyzed in support of the Plan. WECC recommends consideration by decisionmakers for transmission upgrades or other mitigating measures that relieve
congestion on Paths 65 and 66.”
Production cost studies performed using the Gridview program for various Pacific NW
hydro runoff scenarios found that WECC-wide variable operating costs could be reduced
by $5M to $10M in high hydro scenarios for the PDCI upgrade to 3800 MW. In all
scenarios studied, the upgrade to just 3220 MW produced approximately half of the
benefits produced by the full upgrade to 3800 MW.
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The available PDCI capacity from Big Eddy to NOB is fully subscribed and there are over
4800 MW of transmission service requests from Big Eddy to NOB in the BPA long term
firm transmission service request queue. However, the Southern Owners have not been
able to develop sufficient internal benefits for undertaking the higher cost upgrades
beyond 3220 MW at this time. The broad PCRG forum will provide an opportunity for
other interested parties seeking additional PDCI capacity to consider providing support
for AC and DC upgrades to enable the PDCI to operate beyond 3220 MW.
However, recent California ISO studies have indicated that flows from the northwest to
California can be expected to decrease in the future as a result of California enacting
AB32 which encourages the development of in-state renewable generation to meet a
33% RPS and imposes penalties on carbon based resources. As a result, the California
ISO concluded that it would not be economic to increase the capability of the Pacific DC
Intertie.
Given the uncertainty of the future value of a major PDCI capacity increase, the
proposed 120 MW capacity increase, available at a small incremental cost above the
cost of maintaining the existing rating, is a sound investment and preserves the
opportunity for a future increase should the benefits become more certain.
4.2 Conduct Coordination and Outreach
“Cooperate with Project Coordination Review Group members in determining the
benefits and impacts due to the project;
Coordinate project plans with and seek input from all interested members, TEPPC, Subregional Planning Groups, power pools, and region-wide planning group(s); and other
stakeholders including utilities, independent power producers, environmental and land
use groups, and regulators;”
ColumbiaGrid agreed, at BPA’s request, to be the host forum for the Project
Coordination Review. On February 6, 2013, ColumbiaGrid notified the PCC, TSS and
TEPPC that BPA had requested ColumbiaGrid to initiate and facilitate the WECC Project
Coordination Review Process for the PDCI Upgrade Project. Interested parties were
invited to submit a participation form if interested in PCRG participation. The list of
those who expressed an interest in participation is enclosed.
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The first meeting of the PRCG was held April 2nd at the ColumbiaGrid office in Portland.
The meeting attendance list is enclosed, and the meeting presentation materials can be
accessed at:
http://www.columbiagrid.org/event-details.cfm?EventID=897
A second meeting of the PCRG was held on June 5 at the ColumbiaGrid office. The focus
of the meeting was to review and receive comments on this draft report.
PCRG Response List
4.3 Describe Generation Resources and Related Policy Initiatives
“Review how the project improves efficient use of, or impacts existing and planned
resources of the region
Address impacts of project for transmission congestion mitigation,
Describe how the project addresses specific energy policy initiatives;”
The reduced operating constraints coupled with the proposed rating increase will
provide increased opportunities to market surplus Northwest (NW) power to California..
It will help mitigate the increasing problem of NW generation oversupply during high
wind and high hydro conditions in the NW. It will also provide more reliable
performance for south to north flows assuring NW access to available generation
resources in California to meet high winter peak load.
The simpler operating configuration and the modern control and communications
systems will facilitate the possibility of providing dynamic scheduling between the NW
and California. While there are many technical and institutional issues to resolve before
this can be made available, dynamic scheduling could reduce wind generation regulating
burden on NW generation and provide other possible variable generation management
benefits for both regions.
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4.4 Consider Reasonable Alternatives to the Project
“Review the possibility of using the existing system, upgrades or reasonable alternatives
to the project to meet the need (including non‐transmission alternatives where
appropriate);
Address the efficient use of transmission corridors, take rights‐of‐ways, new projects,
optimal line voltage, upgrades, etc. into account;
Specify how the evaluation of the project has taken into account costs and benefits of
the project compared with reasonable alternatives;
Describe potentially parallel or competing projects and consolidate projects where
practicable.”
This project proposes to upgrade an existing transmission path and will make more
efficient use of the 844 mile long Celilo-Sylmar transmission line by increasing the
capacity of the terminal equipment and Celilo-NOB line section.
The only alternative considered was the in-kind, piecemeal replacement of individual
Celilo equipment and systems as they reached end of life which would have eliminated
possibility of a rating increase. The present value cost of this alternative was more than
the complete Celilo converter replacement and upgrade.
There are no known competing or parallel projects at this time.
5.0 Summary
The Project Coordination Review Process has found that the proposed Plan of Service for the
PDCI upgrade to 3220 MW for north to south transfers satisfies the WECC Project Coordination
Review Objectives. The project will resolve the deteriorating reliability of the Celilo Converter
Station and provide an incremental capacity increase that will partially meet demand for
additional PDCI north to south capacity. It will preserve options for future upgrades that would
maximize the utilization of the existing PDCI transmission corridor.
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