Information Document South Area Transmission Constraint Management ID #2013-009R

Information Document
South Area Transmission Constraint Management
ID #2013-009R
Information Documents are not authoritative. Information Documents are provided for information
purposes only and are intended to provide guidance. In the event of any discrepancy between an
Information Document and any Authoritative Document(s) in effect, the Authoritative Document(s)
governs.
1
Purpose
1
This Information Document relates to the following Authoritative Document: Section 302.1, Real Time
Transmission Constraint Management. The purpose of this Information Document is to provide additional
information regarding the unique operating characteristics and resulting constraint conditions and limits in
the South area of the Alberta interconnected electric system.
Section 302.1 sets out the general transmission constraint management protocol steps the AESO uses to
manage transmission constraints in real time on the Alberta interconnected electric system. These steps
are referenced in Table 1 of this Information Document as they are applied to the South area.
2
General
The transmission and generation facilities in the South area are shown in a geographical map in
Appendix 2. For a schematic single line diagram of the South area, see Appendix 3 in this Information
Document.
Several remedial action schemes are in place in the South area to ensure system reliability. The
remedial action schemes for the South area are listed in Appendix 4 with their locations labeled on the
single line diagram located in Appendix 3.
3
Constraint Conditions and Limits
When managing a transmission constraint in the South area, the AESO ensures that transmission line
flows out of the area are managed in accordance with transmission line ratings. These ratings are
established by the legal owner of the transmission facility to protect transmission facilities, ensuring the
continued reliable operation of the Alberta interconnected electric system. The existing remedial action
schemes are designed to ensure line flows are managed to safely maintain emergency transmission line
ratings.
The AESO monitors the remedial action schemes in the South to ensure that they are available when
required. If a remedial action scheme is not available or partially inoperable, the AESO proactively curtails
generation in anticipation of contingencies in order to ensure safe, reliable operation of the system. The
remedial action schemes are outlined in Appendix 4.
The AESO uses wind power management tools to curtail during constraints. Wind power management
does not apply to any wind aggregated facilities that have been constrained down for a local area
constraint. Once the transmission constraint management directive is cancelled, wind power
management is again applied to the asset.
Further descriptions of those transmission constraints and the remedial action schemes are set in the
following subsections 4.1 and 4.2.
1
“Authoritative Documents” is the general name given by the AESO to categories of documents made by the AESO
under the authority of the Electric Utilities Act and regulations, and that contain binding legal requirements for either
market participants or the AESO, or both. Authoritative Documents include: the ISO rules, the Alberta reliability
standards, and the ISO tariff.
Information Document
Page 1 of 8
Posting: 2014-06-26
Information Document
South Area Transmission Constraint Management
ID #2013-009R
3.1
Non-Studied Constraints and Limits
For system conditions that have not been pre-studied, the AESO uses energy management system tools
and dynamic stability tools to assess unstudied system operating limits in real time.
3.2
Studied Constraints and Limits
System studies have identified several specific transmission constraints in the South which have required
the installation of appropriate remedial action schemes to take automatic action to manage the constraint.
The identified constraints and the pool assets that are included in the specific remedial action schemes
are shown in Appendix 4. The constraints can arise under abnormal operating conditions; however,
constraints can also occur under normal operating conditions when there are high levels of wind
production in addition to high British Columbia intertie flows. The constraints on transmission lines 786L,
616L at the Peigan transformer and on transmission line 225L at Spring Coulee often occur under normal
operating conditions.
Loss of a 138 kV path (164L, 863L or 820L) could also result in a possibility of voltage collapse on the
69 kV system (N-1-1 contingency). When such a contingency occurs the AESO prepares the 69 kV
system for the next contingency by proactively curtailing generation as required.
4
Application of Transmission Constraint Management Procedures
The AESO manages transmission constraints in all areas of Alberta in accordance with the provisions of
section 302.1 of the ISO rules. However, not all of those provisions are effective in the South area due to
certain operating conditions that exist in that area. This Information Document represents the application
of the general provisions of section 302.1 to the South area, and provides additional clarifying steps as
required to effectively manage transmission constraints in that area before and after the activation of a
remedial action scheme. The protocol steps which are effective in managing transmission constraints are
outlined in Table 1 below.
Information Document
Page 2 of 8
Posting: 2014-06-26
Information Document
South Area Transmission Constraint Management
ID #2013-009R
Table 1
Transmission Constraint Management
Sequential Procedures for South Area
Section 302.1 of the ISO rules, subsection 2(1) protocol steps
Is the procedure applicable to
the South area?
(a) Determine effective pool assets
Yes
(b) Ensure maximum capability not exceeded
Yes
(c) Curtail effective downstream constraint side export service and
upstream constraint side import service
Yes if effective for the condition
(d) Curtail effective demand opportunity service on the downstream
constraint side
No
(e)(i) Issue a dispatch for effective contracted transmission must-run
No
(e)(ii) Issue a directive for effective non-contracted transmission mustrun
No
(f) Curtail effective pool assets in reverse energy market merit order
followed by pro-rata curtailment
Yes
(g) Curtail effective loads with bids in reverse energy market merit
order followed by pro-rata load curtailment
No
Applicable Protocol Steps
The first step in managing constraints is to identify those pool assets, both generating units and loads,
which are effective in managing constraints. A list of those effective generating pool are identified in
Appendix 1. As per subsection 2(4) of section 302.1, when a transmission constraint has been or is
expected by the AESO to activate a remedial action scheme, the AESO recommences the procedural
sequence in Table 1 (above) once the AESO has ensured that the system is operating in a safe and
reliable mode.
Step (a) in Table 1
The effective pool assets are as shown in Appendix 1.
Step (b) in Table 1
Ensuring maximum capability levels are not exceeded is effective in managing South area transmission
constraints. The effective pool assets that the AESO may curtail are listed in Appendix 1.
Step (c) in Table 1
Curtailing import flows is effective in managing a transmission constraint for constraint one (1) in
Appendix 5. For all other constraints identified in Appendix 4, curtailing import flows is not effective in
managing the transmission constraint.
Step (d) in Table 1
Curtailing effective demand opportunity service on the downstream constraint side is not effective in
managing South area constraints because there is no demand opportunity service in the area.
Step (e) in Table 1
With respect to steps (e)(i) and (ii), there are no transmission must-run contracts in the South area and
using transmission must-run is not effective in managing a transmission constraint.
Information Document
Page 3 of 8
Posting: 2014-06-26
Information Document
South Area Transmission Constraint Management
ID #2013-009R
Step (f) in Table 1
Curtailing effective generating units in reverse energy market merit order followed by pro-rata curtailment
is effective in managing South area transmission constraints. The effective pool assets that the AESO
may curtail are listed in Appendix 1.
Step (g) in Table 1
Because of the configuration of the Alberta interconnected electrical system, curtailing load on the
upstream side is not effective in managing South area constraints.
5
Project Updates
As necessary, the AESO intends to provide information in this section about projects underway in the
South area that are known to have an impact on the information contained in this Information Document.
6
Appendices to this Information Document
Appendix 1 – Effective Pool Assets
Appendix 2 – Geographical Map of the South Area
Appendix 3 – South Area Single Line Diagram
Appendix 4 - Remedial Action Schemes In Effect in South Alberta
Revision History
Version
Posting Date
Description of Changes
1.0
2014-02-27
Initial Release
2.0
2014-04-08
Appendix 1 through 3 amended to include pool asset BSR1
2014-05-29
Appendix 1 through 3 amended to include Old Man River Wind
112S (OWF1).
3.0
4.0
Information Document
2014-06-26
Appendix 3 amended to include Fidler Substation with associated
line amendments and Appendix 4 amended to renumber and add
note concerning Remedial Action Scheme at 103S Goose Lake
893L .
Page 4 of 8
Posting: 2014-06-26
Information Document
South Area Transmission Constraint Management
ID # 2013-009R
Appendix 1 – Effective Pool Assets
The effective pool assets for the South cutplane, listed alphabetically by their pool IDs, are:
AKE1
IEW2
ARD1
KHW1
BSR1
OMRH
BTR1
OWF1
CHIN
RYMD
CR1
TAB1
CRR1
TAY1
CRWD
SCR2
DRW1
SCR3
GWW1
STMY
ICP1
WTRN
IEW1
Information Document
Page 5 of 8
Posting: 2014-06-26
Information Document
South Area Transmission Constraint Management
ID # 2013-009R
Appendix 2 – Geographical Map of the South Area
227S
CUTTING LAKE
852L
753L
512S
HARTELL
253S
BLACKIE
161L
65S
HIGH RIVER
504S
QUEENSTOWN
28S
WEST BROOKS
356S 853L
Milo
911L
180L
447S
ENCHANT
Existing 69 kV Transmission Line
10
0
795L
763L
Nanton
498S
TILLEY
923L
255S
Vulcan VULCAN
Existing Substations
121S
BROOKS
935L
L
763AL
Existing 138 kV Transmission Line
928S
EAST STAVELY
349S
STAVELY
Existing 240 kV Transmission Line
Existing 500 kV Transmission Line
Stavely
197L
Cities
Towns
1201L
763L
1036L
1005L
254S
COALDALE
103S
GOOSE LAKE
396S
PINCHER CREEK
863L
322S
COWLEY RIDGE
239S
CASTLE RIVER
Lethbridge
418S
Ardenville
618S
Wind Farm
RIVERBEND
243S
SODERGLEN
383S
225S
KETTLE'S HILL 312S
MAGRATH
FIDLER
226S
229S
GARDEN CITY
GLENWOOD
6L
L
603L
L
6L
61
164L
514L
17
0
185L
14
162L
379S
415S
WATERTON 502S
DRYWOOD
SHELL WATERTON
225
L
SAINT
MARY
HYDRO
5
22
385S
SPRING COULEE
Cardston
Information Document
Page 6 of 8
172L
593S
LAKEVIEW
314S
IRRICAN POWER
612L
L
Taber 610
134S
TABER
WIND FARM
139S
HILLRIDGE
Coaldale
820L 820AL
336S
FINCASTLE
83S
TABER
607L
120S
492S
Picture Butte
Granum
513S
MONARCH
RANGE PIPEL
UNDBRECK 112S OLD MAN
15S
RIVER WIND
172L
FORT MACLEOD
205S
Castle Rock
L
8
528S
60
59S
Ridge
BLUE TRAIL
725L
PEIGAN
257S
HULL
172BL
786L
421S
HAYS
821L
Claresholm
799S
COLEMAN
158S
VAUXHALL
554S
TRAVERS
485S
BLACKSPRING
RIDGE
315S
CHIN CHUTE
135S
CONRAD
67S
STIRLING
225L Raymond
50
8
L
313S
RAYMOND RESERVOIR
344S
WARNER
Milk River
Posting: 2014-06-26
Information Document
South Area Transmission Constraint Management
ID # 2013-009R
Appendix 3 – South Area Single Line Diagram
Note: 893L Goose Lake (103s) to Oldman River Dam (806s) is decommissioned but can be temporarily
re-energized.
Information Document
Page 7 of 8
Posting: 2014-06-26
Information Document
South Area Transmission Constraint Management
ID # 2013-009R
Appendix 4 – Remedial Action Schemes in South Alberta
#
Remedial Action Scheme Monitoring Point
1
At 799S Coleman 786L (799S Coleman – BC Hydro Natal)
2
At 103S Goose Lake 616L Terminal
3
At 59S Peigan 616L Terminal
4
At 59S Peigan transformer T1
5
Loss of the 225S Magrath transformer T1
6
At 225S Magrath or 618S Riverbend 863L
7
At 103S Goose Lake 613L Terminal
8
At 67S Sterling 225L Terminal
9
At 28S West Brooks 853L Terminal
(not represented in the map)
10
At 15S Fort MacLeod 180L Terminal
11
At 103S Goose Lake 893L
Note: #11 is only enabled if 893L Goose Lake (103s) to Oldman River Dam (806s) is energized.
Information Document
Page 8 of 8
Posting: 2014-06-26