Using WEBSASNERC Learning Objectives Suggested Learning Objectives: Be able to explain the unscheduled flow mitigation plan including the qualification of devices and paths Be able to define terms used in the UFMP Be able to state the calculations WebSAS performs Be able to describe actions taken by operators in response to WebSAS Be able to demonstrate how to get reports from WebSAS Be able to explain the examples in the WebSAS training Remember: Testing should prove the participant can do the above
Using WEBSAS The problem The plan The tools Examples
The problem Loop flow Aka Unscheduled flow
Loopflow and WEBSAS • There are many WECC-approved loopflow training modules. • Loopflow can be dealt with using paper matrices or.. • The Unscheduled Flow Administrative Subcommittee has developed a tool called webSAS written by OATI to implement the Unscheduled Flow Mitigation Plan. • The following slides focus on the UFMP and the use of webSAS to reduce USF.
The Plan The WECC Unscheduled Flow Mitigation Plan
WECC Unscheduled Flow Mitigation Plan • Western version of east-coast TLR. • Most important difference is the western system allows the market to select schedule to curtail vs. TLR curtails automatically • UFM Plan embraces these principles: • Early steps require accommodation of unscheduled flows. • Later steps require Coordinated Operation of Controllable devices unless the PST operator creates an overload or low voltage by altering actual flows. • Subsequent steps require Import Schedule Curtailments (generation re-dispatch). This is where WEBSAS comes in. • Paths and controllable devices are “qualified” to take part in the plan. • Emergency operation is allowed to help non-qualified paths.
WECC UFMP • The plan requires both tagged and non-tagged transactions be assessed and curtailed (as necessary). The webSAS tools described later deals only with tagged transactions. • Failure to comply with UFMP can result in RMS sanctions (either a letter or monetary sanctions).
UFMP Terms • Qualified path: A path proven to suffer from unscheduled flows • Qualified device: A device proven to be effective in reducing unscheduled flow, usually on more than 1 qualified path. • Controllable device (series caps, PST’s etc). • + TDF: means your transaction (aka off-path schedule) is loading someone else’s path (bad) • -TDF: Means your transaction is unloading someone else’s path (good) • Plan year 1 = 1995, PY2=1996 etc. • Zones: Sources which are electrically very close may be in the same zone. Schedules move power from one zone to another
UFMP Terms • Implement – A tag is implemented when it approved and accepted and is in the scheduler. Prior to this, a tag is pending and may be denied or accepted. • COPS – Coordinated Operation of Phase Shifters, usually coordinated by the RD reliability coordinator. • Accomodation – Accepting a certain amount of unscheduled flow on a qualified path • Hubbing – A marketing tool for scheduling energy deliveries to a POR/POD (the hub) that does not represent a true sink. This is similar to scheduling energy receipts from a POR/POD (another hub) that isn’t a true source.
UFMP core principles • The following chart shows the core principles of the plan and details specific actions triggered by specific flow levels. • The TDF’s referred to are determined twice each year by the WECC staff and programmed into WEBSAS. • Remember: In order to provide 2.5 MW relief on a path where your schedule has a 25% TDF, you must curtail the schedule by 10 MW.
Accommodate 5% Largest TDF’s curtail first COPS begins at step three Plan has 9 steps
1. Dispatcher – cisosched1 2. Phone – 916-351-2493 3. Action Required – See Below 4. Qualified Path – Path 66 – COI 5. Path Flow 3798 6. Transfer Capability – 3784 7. Schedule – 3288 8. Path Operator – CISO 9. Initiating Party – CISO 10. Device Action – Start Coordinated Controllable Device Operation 11. PPT Action Date – 05/31/05 12. PPT Action Time – 1400 13. PPT Action Zone – PPT 14. Schedule Curtailment – Start Indicated Level of Schedule Curtailments (See Below) 15. Schedule Curtailment Date – 05/31/05 16. Schedule Curtailment Time – 1400 17. Time Zone – PPT 18. Level – Fourth Level (Step 9) 19. Comments – Path 66 is continuing to experience USF constraints, they are accommodating 7% or more of USF on the path and is invoking Step 9, Level Four Curtailment of the contributing schedules WECC MessageFrom: OATI1Sent: Tuesday, May 31, 2005 13:15To : ALL WSCCSubject: Path 66 – COI Unscheduled Flow Reduction Procedure
Steps 1 & 2: Controllable devices in the overloaded path & Accommodation • Note the first step is for the qualified path operator to try to reduce flows on their own path using: • Series caps or inductors • Using PST’s in the overloaded path • The second step is accomodation of 5% unscheduled flows. More accommodation is required in later steps. • For example, a path with an OTC of 3784 would put in-place a scheduling limit of .95*3784 or 3595 to accommodate 5% unscheduled flow.
WECC Unscheduled Flow Mitigation Plan (UFMP) Step 3 • MORC says if a PST is not on neutral, it must meet schedule. • This protects an owner from being expected to always use a PST to meet schedules; natural flow is OK. • Exception in Administrative Procedure 8 allows incremental adjustments to PST to help unload a qualified path. An incremental adjustment is when a PST is moved a certain number of taps rather than all the way to schedule. • MORC also says a PST cannot be moved beyond schedule. • PST’s must be within two (2) taps of schedule if not on neutral.
During Coordinated Operation of Phase Shifters (COPS) • Takes place after initial accommodation of unscheduled flows by qualified path operator. • Shouldn’t go beyond schedule on PAR • Shouldn’t increase USF on the constrained path unless it relieves a similar overload or curtailment elsewhere. (beginning of competing path AP004)
Steps 4 through 9 • Each step requires progressively more accommodation and more off-path import schedule curtailments
UFAS Administrative Practices • UFAS Administration Practice 001- Procedure for qualifying a controllable device (to get $$ for moving the device). • UFAS Administration Practice 002 - qualified path needs to be loaded to 95% or more to request relief from unscheduled flow • UFAS Administration Practice 003 – Procedures for transfer path qualification
UFAS Administrative Practices • UFAS Administration Practice 004 – Competing requests for qualified path relief (matrix for Paths 36 and Path 66) • Rocky Desert Reliability Coordinator coordinates competing requests for relief
Peace River British Alberta Columbia Canada Seattle Washington Portland Area Montana Celilo Pacific Colstrip Oregon Ocean Idaho Malin Wyoming Midpoint Borah Round Mountain Laramie Jim Nevada Bridger Salt Lake River City Area San Francisco Area Denver Utah Area Las Vegas Area Four Colorado California Corners Market New Place Los Mexico Angeles Area Albuquerque Phoenix Area Arizona San Diego Tucson Area Mexico El Paso Path 66 Path 36
Competing Paths • Goals: • Maximize the total unscheduled flow relief brought to both competing qualified paths. • Causes: • COPS for one path overloads another • 2 paths encounter congestion for normal patterns of generation & load • Solution: • Build matrices to: • Assure significant BENEFIT to one while not being a significant detriment to the other.
Schedules can affect two paths in three ways • Hurt both • In this case, curtail the schedule by the amount corresponding to the largest Transfer Distribution Factor (TDF) • Help both • Don’t curtail • Help one and hurt the other • Curtail only if you help one TWICE as much as you hurt the other.
PSC Cherokee to LDWP Example Path 36 TTC = 1424 Path 66 TTC= 4175 Cherokee LA COPS of TOT 2
Cherokee to LDWP TDF’s • On Path 66, TDF = + 37 • 37% of a schedule from Cherokee to LA increases loading on path 66 • On Path 36, TDF = - 35 • 35% of a schedule from Cherokee to LA decreases loading on path 36 • In other words, this schedule LOADS path 66 and UNLOADS path 36.
AP004 • If Positive TDF/Positive path rating is greater than TWICE Negative TDF / Negative path rating, then curtail the schedule which will unload path 66 by twice what it loads path 36. • Also, AP004 instructs the RDRC to go immediately to step 8 accommodation level and step 9 curtailment level.
UFAS Administrative Practices • UFAS Administration Practice 005 – rapid advance to latter steps of procedure • UFAS Administration Practice 006 – Use of TOT 2 phase shifters for coordinated cut-plane operation (allows total TOT2 to meet MORC, vs. TOT2a, or b, or c)
UFAS Administrative Practices • UFAS Administration Practice 007 – Curtailment event evaluation selection process • UFAS Administration Practice 008 – Use of phase shifters to provide obligated path relief
PST’s require two special exemptions from the UFMP • Owners of any PST’s (not just qualified) may be exempt from curtailing certain schedules between neighbors. • Schedules to neighbors through qualified PST’s operating under COPS may also be exempt. These schedules are identified by POR’s/POD’s on either side of the PST AND by source and sink in the CA’s immediately adjacent to the PST. • Owners of PST’s may use the PST to unload a qualified path in-lieu of curtailing a schedule
PST’s holding schedule with neighbor 1. Owners of PST’s may be exempt from curtailing certain schedules. • If COPS doesn’t provide all of the relief required and the UFMP is moving into the schedule curtailment steps (steps 4-9), then… • Schedule curtailments are required from all (including PST owners) and… • Whether a PST is holding schedule (act=sched) OR a qualified PST is participating in COPS (in COPS, PST actuals need NOT equal to schedules)… • Schedules across the PST between adjacent CA’s will not be curtailed
Use of PST’s vs. curtailing schedules 2. Owners of PST’s may use the PST to unload a qualified path in-lieu of curtailing a schedule • It is OK to move the PST away from schedule or neutral in-lieu of curtailing schedules. This is referred to as incremental PST operation. • The PST owner must demonstrate the effectiveness of the incremental change on reducing unscheduled flows on the qualified path. • The PST must not be participating in COPS for this incremental operation.
AP008 using PST vs curtailment Use of PST operation to meet a Member’s Path relief obligation under the Schedule Curtailment phase of the Procedure. • “Schedule reductions shall not be required by the Member to the extent that controllable elements (which are not operated in a coordinated manner) are incrementally operated during the USF event to achieve an equivalent reduction in USF across the constrained Qualified Transfer Path. The Member shall be able to document and demonstrate that an equivalent USF reduction has been achieved through the use of the controllable element.” • Allowed relief under this provision of AP008 is only available to the Member that operates a controllable device as only this member can document and demonstrate an equivalent USF reduction. This relief is a function of the incremental operation of a phase shifting transformer or other controllable device and cannot be identified by adjustment or curtailment of a NERC Transaction Tag. Therefore, this relief would be identified directly in webSAS by the Control Area responsible for PST operation.
One method to document and demonstrate the use of a PST vs Tag Curtailments • Determine the relief required on the qualified path • Contact the reliability coordinator and path operator and express your intentions to use the PST vs curtailing tags. • Move the PST and verify the affects on the path suffering USF by talking to the path operator.
Examples of AP008 • Colstrip to Bonanza (Utah) • Colstrip to Northeastern Colorado • Colstrip to LDWP • Colstrip to PACW(Wyoming)
AP008 Example 1 (see next slide) • Colstrip to Bonanza (Utah) TDF on path 30 (TOT1 east to west ) = +34.5. This means 34.5 % of a schedule from CS to Bonanza flows on path 30 • Step 9 UFMP would require a 25% reduction in any schedule between the zone containing CS and the zone containing Bonanza • If WEBSAS identified 4 schedules totaling 80 MW’s between these two zones, 27.6 MW’s (34.5%) would be flowing on Path 30. • The UFMP would require 6.9 MW (25% of 27.6 MW) reduction in Path 30 flows • NWMT may choose to incrementally change the PST’s at Montana-Southeast to reduce the flow on Path 30 by 6.9 MW. • If NWMT reduced the PST flows at MTSE by 6.9 MW, NOT all of the 6.9 would show up on Path 30. • Thus, NWMT must change PST flows more than 6.9 to assure enough relief of Path 30.
Path 30 E to W, CS-Bon Example CS 100 MW schedule NE Col Bon Path 30 TDF = 34.5
AP008 Example 2 • Colstrip to Northeastern Colorado TDF = -28.6 meaning a 100 MW schedule from CS to NE Colorado reduces east to west flows on path 30 by 28.6 MW.
Path 30 E to W CS-NE Colorado Example CS 100 MW schedule NE Col Bon Path 30 TDF = 28.6
TDF’s for Colstrip Schedules affecting other qualified paths • Path 15 • Path 66
CS TDF’s for Path 15 (path 15 South to North) CS CS PACW/SOR LA CS-PACW/SOR = +9.7 CS-LADWP TDF = -70.8
CS TDF’s for Path 66 (COI North to South) CS CS PACW/SOR SMUD CS – PACW/SOR = -8.8 CS- SMUD = +83.5
Actual AP008 examples • To be provided later
UFAS Administrative Practices • UFAS Administration Practice 009 – In the past, any schedule that affected a qualified path would not be allowed to start during a UFM Event, regardless of how small the affect is. • This could shut down 1000’s of MW’s of schedules for almost no reason. • AP009 says that if a schedule has a very small (<5%) affect on a qualified path, allow the schedule to start because the system has at least +/- 5% incertainty.
The tools Websas is a tool developed by OATI to implement the plan. There are non-webSAS methods also, primarily using paper matrices. The following is for webSAS only.
UFMP Tools • WEBSAS is the Security Analysis Service program from OATI to coordinate unscheduled flow mitigation in the WECC Interconnect • Determines relief requirements • Suggests on and off-path schedule curtailment options • Ties to e-tag and WECC message net • WEBSAS determines affect of on and off-path schedules on path that is loading due to USF. • WEBSAS then recommends schedule cuts
WEBSAS needs or calculates the following: • Path Operator establishes: • Stage (step) of USF event • Path(s) suffering USF • Websas determines: • Your implemented tags from zone to zone • Your TDF’s from zone to zone affecting the suffering path • The MW’s relief you could provide given tags you are sinking and their TDF’s • Is it the top of the hour? • Doesn’t need to know: • Your total net interchange schedule • Ramp information (WEBSAS uses fully ramped-in tag MW’s)
WEBSAS Curtailments • On-path tags are on the qualified path and a subject to accommodation curtailments. • Off-path tags are those on paths parallel to the qualified path and are subject to relief mitigation. • The WECC member load control area or the load serving entity (or their assigned agent) are responsible for the curtailments of off-path schedules based on TDF’s.
From the UFAS FAQ list on the WECC website Question - The Unscheduled Flow Mitigation Procedures (USF) describe a Receiver as being responsible for providing USF relief. How has this been interpreted by WECC with relation to E-tags? Answer – WECC has determined that the Receiver is the Load Serving Entity (LSE) on the E-tag. The entity responsible for providing the relief is dependant upon if the LSE on the E-tag is a WECC member or not, as follows: • If the LSE on the E-tag is a WECC member, then that LSE is responsible for providing relief requirements under the USF. • If the LSE on the E-tag is NOT a WECC member, then the Load Control Area on that E-tag is responsible for providing relief requirements under the USF. Reference USFMP Section 9.h.ii
Member LSE’s • The host control area won’t see the tags to be curtailed if the LSE is a WECC member unless the CA is an agent for the LSE. • If the CA is not an agent for the LSE, the LSE is responsible for curtailments. • Also, a member LSE practicing “hubbing” is not exempt from making tag curtailments. They may assign their responsibility to their host control area if the host CA is their agent .