[Capacity-l] Powerex's Concerns about the August 2007
InitialCoordinated Outage Plan
Shannon,Janet - TOD-DITT1
jshannon at bpa.gov
Wed Jun 20 07:50:22 PDT 2007
Greetings,
Thank you for expressing you comments and concerns. This information
will be taken under advisement.
Thank you,
Janet Shannon
BPA Dittmer Outage Office
________________________________
From: capacity-l-bounces at listserv.bpa.gov
[mailto:capacity-l-bounces at listserv.bpa.gov] On Behalf Of Dobson-Mack,
Gordon
Sent: Wednesday, June 20, 2007 7:40 AM
To: Transmission Capacity E-mail Forum; Capacity Forum; Daly,Patricia A
- TOD-DITT1; Juj,Hardev S
Cc: Jackson II,Jerry L - TOT-DITT2
Subject: [Capacity-l] Powerex's Concerns about the August 2007
InitialCoordinated Outage Plan
Importance: High
Pat and Hardev,
Powerex appreciates having the opportunity to comment on the August
outage plan and we recognize the challenging position that TBL is in
when you coordinate transmission outages for the region.
For the July and August 2007 outage plans we have deliberately sent our
comments to the Transmission Capacity Forum so that TBL will be able to
respond to our questions. We believe it is important that transmission
outages and their potential impacts be discussed openly so that as a
region we can work together to mitigate the impact of outages.
We are concerned that some of the planned transmission outages will
result in significant transmission congestion in July and August;
derates in the North-to-South transfer capability of the Northern
Intertie will constrain an already tight resource supply in the middle
of summer. We believe there are options to significantly reduce the
impact of these outages and we would like to discuss them with BPA, SCL
and any other interested party. We recommend that BPA convene an open
meeting to discuss ways to reduce the impact of the planned July and
August outages.
The details of our concerns regarding July and August outages are
summarized below.
SCL Outages of Concern in July/August 2007:
1) SCL's Canal-Broad St 115 kV line out of service (#178572) starting 13
August 2007
Estimated Westside NI N-S capacity = 700 MW 13-15 August A derate
of 2150 MW from the Northern Intertie path rating
Scheduling SCL's Canal-Broad St 115 kV line out of service (#178572)
simultaneously with SCL's SnoKing-Maple Valley lines (#164725 & #164732)
will result in SCL's University-Broad St's 115 kV line being a single
line in parallel with the 500 kV path. To prevent overloads on this 115
kV line, BPA plans to derate the 500 kV Intertie with Canada (the
Northern Intertie - NI) and it is expected that the derates will be
worst at high temperatures (85F) when the WECC needs the capacity the
most. Consequently, it is very important that the Canal-Broad St 115 kV
line outage start after the SnoKing-Maple Valley lines are returned to
service.
Recommendation: Delay the start of the Canal-Broad St
outage (#178572) until 16 August 2007, after SK-MV lines are returned to
service
2) SCL's University-Broad St 115 kV line outage (#177595) is scheduled
to be out of service through to 3 August 2007 (according to latest July
plan)
Estimated Westside NI N-S capacity = 1200 MW 25 July -3 August
A derate of 1650 MW from the Northern Intertie path rating
Scheduling SCL's University-Broad St 115 kV line outage line out of
service (#177595) simultaneously with SCL's SnoKing-Maple Valley lines
(#164725 & #164732) will result in SCL's Canal-Broad St's 115 kV line
being a single line in parallel with the 500 kV path. To prevent
overloads on this 115 kV line, BPA plans to derate the Northern Intertie
thereby stranding generation capacity in BC that could be needed within
the WECC during a summer heat wave. Consequently, it is very important
that the University-Broad St line be completed before the SnoKing-Maple
Valley lines are taken out of service.
Recommendation: SCL should do what is necessary to return the
University-Broad St line to service before 25 July 2007, before the
SK-MV lines are removed from service
As a secondary note, SCL's University-Broad St 120 kV line outage
(#177595) was added to the July 2007 outage plan after the normal 45 day
outage planning process, hence I was not aware until June 20 of the
expected impact of SCL's plan for this line to be out of service
concurrently with SCL's SnoKing-Maple Valley lines (#164725 & #164732).
3) SCL's SnoKing-Maple Valley #1 & #2 230 kV lines out of service from
July 25 - August 15 with the SCL's Maple Valley - Duwamish 230 kV line
Estimated Westside NI N-S capacity = ~1600 MW
A derate of 1250 MW from the Northern Intertie path rating
For these outages the NI derates result from having BPA having to
prepare to withstand the next worst contingency ("N-2: Maple VL- Echo
Lake 500kv and Maple VL - Rocky Reach 345kv line") in order to prevent
overload of the "Broad ST- University 115 kV line".
This is at least a Category C outage (N-2-2) and our studies indicate
that if the next worst contingency did occur that both University-Broad
St and Canal-Broad St would trip on overcurrent causing the SCL 115 kV
system to separate, without any loss of load.
Preferred recommendation:
- SCL arm its RAS to trip University-Broad St & Canal-Broad St 115kV
lines for loss of the Maple Valley 500/230 kV Transformer. BPA
operations would then model this action in its nomogram studies.
Alternative recommendation:
- BPA Operations confirm that after contingencies causing
overloads of the University-Broad St & Canal-Broad St lines that a
controlled separation of the SCL system should occur when the lines'
overcurrent relays trip. Having a planned/controlled response to
Category C contingencies, would then enable BPA to ignore those
contingencies that could cause overloads of the University-Broad St and
Canal Broad St lines. As such, we would expect at least the following
contingencies to be ignored:
o "N-2: Maple VL- Echo Lake 500kv and Maple VL - Rocky Reach
345kv line"
o "BFR: Maple Valley 230kV Bus Section #3 & Klahanie"
4) SCL's Canal-Broad St 115 kV line out of service (#178572) 13 August
2007 - 19 October 2007
Estimated Westside NI N-S capacity = ~1600 MW A
derate of 1250 MW from the Northern Intertie path rating
For this outage the NI derates result from having BPA having to prepare
to withstand the contingencies that would result in overloads of the
"University - Broad ST 115 kV line". Our studies indicate that if this
line trips on overcurrent that the SCL 115 kV system would separate,
without any loss of load.
Preferred recommendation:
- SCL arm its RAS to trip University-Broad St & Canal-Broad St 115kV
lines for loss of the Maple Valley 500/230 kV Transformer. BPA
operations would then model this action in its nomogram studies.
Alternative recommendation:
- BPA Operations confirm that after contingencies causing
overloads of the University-Broad St & Canal-Broad St lines that a
controlled separation of the SCL system should occur when the lines'
overcurrent relays trip. Having a planned/controlled response to
Category C contingencies, would then enable BPA to ignore those
contingencies that could cause overloads of the University-Broad St and
Canal Broad St lines. As such, we would expect at least the following
N-1-2 contingencies to be ignored:
o "N-2: Maple VL- Echo Lake 500kv and Maple VL - Rocky Reach
345kv line"
o "BFR: Maple Valley 230kV Bus Section #3 & Klahanie"
5) SCL's University-Broad St 120 kV line outage (#177595) ?? June -
through hopefully no later than 24 July 2007
Estimated Westside NI N-S capacity = ~1800 MW A
derate of 1050 MW from the Northern Intertie path rating
For this outage the NI derates result from having BPA having to prepare
to withstand the contingencies that would result in overloads of the
"Canal - Broad ST 115 kV line". Our studies indicate that if this line
trips on overcurrent that the SCL 115 kV system would separate, without
any loss of load.
Preferred recommendation:
- SCL arm its RAS to trip University-Broad St & Canal-Broad St 115kV
lines for loss of the Maple Valley 500/230 kV Transformer. BPA
operations would then model this action in its nomogram studies.
Alternative recommendation:
- BPA Operations confirm that after contingencies causing
overloads of the University-Broad St & Canal-Broad St lines that a
controlled separation of the SCL system should occur when the lines'
overcurrent relays trip. Having a planned/controlled response to
Category C contingencies, would then enable BPA to ignore those
contingencies that could cause overloads of the University-Broad St and
Canal Broad St lines. As such, we would expect at least the following
N-1-2 contingencies to be ignored:
o "N-2: Maple VL- Echo Lake 500kv and Maple VL - Rocky Reach
345kv line"
o "BFR: Maple Valley 230kV Bus Section #3 & Klahanie"
There is an opportunity to reduce operating risk overall by mitigating
the impact of SCL's planned outages. A meeting should be convened with
BPA, SCL, PWX and any other interested party to discuss what measures
can be taken, in conformance with WECC criteria, to ensure that the
impacts of needed transmission outages can be minimized. I look to BPA
to take the initiative and convene this meeting.
If you have any questions, please call.
Sincerely, Gordon
Gordon P. Dobson-Mack
Manager, Transmission Issues
Powerex
Phone: 604.891.6004 Fax: 604.891.5045
________________________________
From: Dobson-Mack, Gordon
Sent: Monday, June 04, 2007 9:39 AM
To: 'Transmission Capacity E-mail Forum'
Cc: 'bpaoutage at bpa.gov'; jsnewby at bpa.gov; 'jljacksonii at bpa.gov'
Subject: Powerex's concerns about the SnoKing-Maple Valley 230 kV line
outages 25 July-15 Aug
Pat, Janet, Jeff & Jerry,
Powerex is still very concerned about SCL's outages 164725 and 164732
that are scheduled for July 25-August 15. During these outages the
SnoKing-Maple Valley 1 & 2 230kV Lines will be taken out of service as
part of an I-405 construction project.
As these outages are scheduled in the middle of summer, they could have
a significant negative impact on system reliability if temperatures are
high during this three week outage period. Consequently, we believe
that as a region we need to explore options for mitigating the impact of
this outage. In cases like this, it is important to understand the
outage risks and weigh them against other regional risks, such as
resource adequacy.
To facilitate a regional dialogue, we offer the following thoughts. We
welcome feedback either through this E-mail forum or through a NTAC or
NWPP meeting convened to mitigate the impact of this planned outage.
Background: With SCL's SnoKing-Maple Valley 1 & 2 230kV Lines Out of
Service, BPA Operations must prepare for the next worst contingency,
namely
"N-2: Maple VL- Echo Lake 500kv and Maple VL -
Rocky Reach 345kv line"
Issue: SCL's Broad ST- University 115 kV line will
overload if the N-2-2 contingency described above occurs.
Problem: North-to-South transfers the Northern Intertie will be
derated in anticipation of a possible N-2-2 contingency; in essence, a
potential load service problem will causing derates of Inter-regional
transfer capability.
Key Questions:
Q1: What is impact of SCL's Broad ST- University 115 kV line
overloading after this contingency? Specifically, will SCL's 115 kV
lines in North of Broad street auto-sectionalize via the overcurrent
relays on the impacted lines?
Q2: What is the probability of a "N-2: Maple VL- Echo Lake 500kv
and Maple VL - Rocky Reach 345kv line" occurring during the 3 week
period of 25 July - 15 August 2007?
I look forward to working with you, SCL and other interested parties in
the region to minimize the impact of the planned SnoKing-Maple Valley
outages.
Regards, Gordon
Gordon P. Dobson-Mack
Manager, Transmission Issues
Powerex
Phone: 604.891.6004 Fax: 604.891.5045
________________________________
From: Dobson-Mack, Gordon
Sent: Friday, May 18, 2007 4:52 PM
To: 'Transmission Capacity E-mail Forum'
Cc: 'bpaoutage at bpa.gov'
Subject: Powerex's comments on the July 2007 Initial Coordinated Outage
Plan
Pat,
Thanks for the opportunity to comment on the July 2007 Coordinated
Outage Plan. Our primary concern is related to the Northern Intertie:
SCL has scheduled outages of the Snoking- Maple Valley #1 and #2 230kv
lines from Jul 25 to Aug 15. As a result of these outages, the forecast
North to South OTC of the Westside of the Northern Intertie is 1200MW.
As these outages are scheduled in the middle of summer, they could have
a significant impact on system reliability if high temperatures result
in transmission congestion at the same time that generation resources
become constrained as they did on July 24, 2006. Consequently, we
believe that it is important to find ways to mitigate the impact of
these outages. Options could include:
a) Deferring outages 164725 and 164732 (I-405 Rework: adding new
steel poles to raise lines) so that the SnoKing-Maple Valley lines are
not taken out of service until after September 15, 2007;
b) Shortening the duration of the outages and/or staggering the
line outages so that they are not both out of service concurrently;
c) Reducing the impact of the next worst contingency "BFR: Maple
Valley 230kV Bus Section #3 & Klahanie" so that four more lines are not
forced out of service with a Bus Section #3 Breaker Failure. For
instance, if it was possible to temporarily move the Maple Valley
500/230 kV transformer onto a different bus section, then the impact of
a Bus Section #3 BFR would be significantly reduced;
d) Reducing the parallel flow on SCL's BROAD ST to UNIVERSITY
115.00 kV line either by sectionalizing or increasing the impedance of
the 115 kV path in parallel with the 500 kV lines between Monroe and
Raver when there is risk to system reliability.
Regards, Gordon
Gordon P. Dobson-Mack
Manager, Transmission Issues
Powerex
Phone: 604.891.6004 Fax: 604.891.5045
________________________________
From: capacity-l-bounces at listserv.bpa.gov
[mailto:capacity-l-bounces at listserv.bpa.gov] On Behalf Of Daly,Patricia
A - TOD-DITT1
Sent: Wednesday, May 16, 2007 11:37 AM
To: Capacity Forum
Subject: [Capacity-l] July 2007 Initial Coordinated Outage Plan
The Coordinated Outage Plan for July 2007 has been posted and can be
reviewed at:
http://www.transmission.bpa.gov/OASIS/BPAT/outagecoord/febout.htm
<http://www.transmission.bpa.gov/OASIS/BPAT/outagecoord/febout.htm>
Thank you,
Patricia Daly
BPA Dittmer Outage Office
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