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Using WEBSAS NERC 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

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using websas nerc learning objectives

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


the problem

The problem

Loop flow


Unscheduled flow

loopflow and websas
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 Plan

The WECC Unscheduled Flow Mitigation Plan

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
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 terms9
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
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
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
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
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
Steps 4 through 9
  • Each step requires progressively more accommodation and more off-path import schedule curtailments
ufas administrative practices
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 practices20
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


























Salt Lake


City Area

San Francisco























San Diego




El Paso

Path 66

Path 36

competing paths
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
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
PSC Cherokee to LDWP Example

Path 36

TTC = 1424

Path 66

TTC= 4175




cherokee to ldwp tdf s
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.
  • 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 practices27
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 practices28
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
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
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
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
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
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
Examples of AP008
  • Colstrip to Bonanza (Utah)
  • Colstrip to Northeastern Colorado
  • Colstrip to LDWP
  • Colstrip to PACW(Wyoming)
ap008 example 1 see next slide
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
Path 30 E to W, CS-Bon Example


100 MW schedule

NE Col


Path 30 TDF = 34.5

ap008 example 2
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
Path 30 E to W CS-NE Colorado Example


100 MW schedule

NE Col


Path 30 TDF = 28.6

cs tdf s for path 15 path 15 south to north
CS TDF’s for Path 15 (path 15 South to North)





CS-PACW/SOR = +9.7

CS-LADWP TDF = -70.8

cs tdf s for path 66 coi north to south
CS TDF’s for Path 66 (COI North to South)





CS – PACW/SOR = -8.8

CS- SMUD = +83.5

actual ap008 examples
Actual AP008 examples
  • To be provided later
ufas administrative practices44
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

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
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
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
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
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
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 .
ufmp tools52
UFMP Tools
  • WEBSAS uses a matrix to determine the affect of a schedule from one zone to another on the path experiencing the overload due to unscheduled flows.
  • The matrix provides Transfer Distribution Factors (TDFs) to determine the % of on and off-path schedules that shows up on overloaded path.
    • No action required if the TDF is less than 10%
  • WEBSAS snaps a schedule picture and applies the TDF’s when UFS event is announced on WECC_NET.
  • WEBSAS then recommends tag cuts for each entity that will reduce overloads on path suffering due to USF.
  • The tag cuts are based on the impact a particular schedule has on the over-loaded path.
add alternative action
Add Alternative Action
  • If the operator desires to provide required relief via some alternative mechanism rather than curtailing E-tags (perhaps raising generation at a particular unit or issuing a counterflow transaction or operating a PST), then the operator should:
    • Leave all E-tags unselected and select “Confirm”
    • In the new window that opens, select “Add Alternative Action”. Type in the text notes describing the alternative action and select confirm. No E-tag curtailments will occur, but your text entry will be logged for WECC staff to review.
execution effective time
Execution & Effective Time
  • Execution Time: When the path operator requests a USF event (asks for relief). This is when the event is called.
  • Effective Time: Top of hour following execution time. This is when the event actually starts and when webSAS determines compliance.
  • Pre-event tags are any tags implemented before the execution time
  • Post-event tags are any tags implemented after the execution time.
pre event tag example
Pre-event tag example
  • Let’s say a tag is approved and accepted and is in the scheduler (either real-time or day-ahead) and power is to begin to flow at 14:50 (as the ramp begins) and is supposed to flow for three hours.
  • Let’s also say an event is called at 14:20 (execution time) with an effective time of 15:00.
  • Because the tag was in the scheduler prior to execution time, webSAS treats this as a pre-event tag.
wecc message
WECC Message

Execution Time

From: OATI1

Sent: Tuesday, May 31, 2005 13:15


Subject: Path 66 – COI Unscheduled Flow Reduction Procedure

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

Effective Time

pre post event tags
Pre & Post event tags
  • There are different rules for curtailing pre and post event tags.
  • Pre-event tags with TDF’s as high as 9.99% may not be curtailed
  • Post-event tags with TDF’s as low as 6% will be curtailed
    • The tags with TDF’s between 6% and 9% are most susceptible to NOT flowing post event and flowing pre-event.
your actions to curtail tags may help or hurt
Your actions to curtail tags may help or hurt

2) WEBSAS calculates you should help this much.

1) USF events of interest start with you hurting path.

3) WEBSAS helps you move from NEG to POS

POS relief provided

NEG relief provided


You are hurting (loading) the suffering path

You are helping (unloading) the suffering path

websas output curtailed schedules
WEBSAS output curtailed schedules
  • Relief required: WEBSAS calculates your responsibility for relief on the suffering path to be this much. This is all based on tags sinking in your control area and their TDF percentages.
  • This amount is calculated when the event is called, that is, the execution time.
  • The amount is based on all current IMPLEMENTED tags.
  • This value does not change.
relief required
Relief Required
  • Relief Required is calculated for each entity by WEBSAS using the TDF matrices at execution time.
    • POS Relief Required means the receiving entity (i.e. your control area) must take action to provide some relief.
    • NEG Relief Requirement means the receiving entity (i.e. your control area) took actions prior to the execution time that helped relieve the path.
relief provided
Relief Provided
  • Relief Provided is calculated between execution time and effective time.
    • POS Relief Provided indicates you have taken some action to relieve the suffering path and you have helped.
    • NEG Relief Provided means you have taken some action to LOAD up the suffering path and you haven’t helped at all.
relief provided64
Relief Provided
  • This value must be equal to or greater than Relief Required in order to be compliant.
  • Remember the relief provided is measured as you are going into the top of the hour.
websas output floating box
WEBSAS output Floating Box
  • (1) Post USF tags Relief: This value is the result of applying the TDF’s to all “Implemented” tags after the USF event is called at the execution time. This number can change as tags come in or are withdrawn.
    • A negative value means you are hurting the suffering path.
    • A positive value means you are helping the suffering path.
floating box 2 must refresh to update
Floating Box 2 (must refresh to update!!)
  • Floating Box 2: IMPLEMENTED E-tag Adjustments
  • This value is calculated form all E-tag adjustments, curtailments, and extensions that went IMPLEMENT after the USF event was called.
  • The value is Positive to help or Negative to hurt the current USF event.
  • This number can change as more E-tags go Implemented.
floating box 3 must refresh to update
Floating Box 3 (must refresh to update!!)
  • Floating Box 3: webSAS relief selected adjustment
  • This value is calculated from all E-tags selected in the webSAS tool at the current time.
  • This number fluctuates as new E-tags are selected within the current display.
  • This is an aid to help determine if the selected E-tags provide adequate relief.
floating box68
Floating Box

Box 3 represents adjustments made with WEBSAS

The word “Implemented” refers to tag status and means the tags and/or tag changes affecting your ACE.

floating box69
Floating Box

Turns Green if enough has been curtailed. Main page also turns green/red depending on if you’ve curtailed enough.

This number will change as tags & changes are implemented

These numbers only change when curtailment has been implemented with WEBSAS.

floating box example
Floating Box Example
  • Using the TDF’s applied to active schedules when the USF event was called (execute time), WEBSAS came up with your relief required = 4.5 MW
  • Post-event tags have come in that hurt the victim path by 11.6 MW
  • Curtailments (non-WEBSAS), adjustments, counterschedules, and extensions have been implemented that have helped by 5.1 MW’s
  • So you need to use WEBSAS to get from -6.5 (hurting) to + 4.5 (helping) or about 11 MW’s of further actions required to reduce your impact on victim path.
floating box example71
Floating box example

(2) WEBSAS has calculated your help so far to be

+ 5.1 MW

You need to use WEBSAS to get 11 MW’s more relief on the victim path.

(3) Your initial relief required was 4.5 MW’s








(1) Due to post-event schedules, you are now hurting the other path by 11.6 MW

event time reset
Event time reset
  • For the first years of the plan, a USF event could go on for days.
  • Timer now starts when moving past step 3 of procedure.
  • Event terminates whenever the event goes below step 4.
post event tag problem
Post-event tag problem
  • Let’s say the original WEBSAS snapshot showed you had no “relief required”. In other words, at execution time, none of your tags affected the path suffering USF.
  • Also, let’s say before the ramp, you get 3 tags with TDF’s higher than 5% on the suffering path and you IMPLEMENT the schedules.

•   On the hour, when WEBSAS does another snapshot to send to WECC RMS group to determine compliance, your relief provided will be NEGATIVE and will show up in the “IMPLEMENTED E-tag adjustments” in the floating box because of the 3 new IMPLEMENTED tags.

solution to post usf tag problem
Solution to post-USF tag problem
  • Refresh the screen often, especially around 00:50 to catch late tags.
  • Once refreshed, your floating box will properly reflect your actions and obligations.
welcome screen
Welcome Screen
  • Look for your control area name and make sure it is correct
  • Look at your user name to make sure it is correct (not all users have permission to curtail tags).
  • Look at the messages for any recent changes. Often specific Change Orders are listed.
  • Note the time and verify your time zone
transaction screen
Transaction Screen
  • This screen shows all tags sinking in your control area for which you are the agent
    • View transactions means see current hour transactions only.
    • View next hour transaction changes means show this hour tags PLUS next hour tag MW’s, changes or terminations.
    • Transaction and Active MW’s will differ if there has already been a curtailment.
nwmt may be required to reduce these schedules for a path 20 c event
NWMT may be required to reduce these schedules for a path 20-C event

ToolsTransaction Contributions

transaction contributions
Transaction Contributions
  • Shows how much each OFF-path tag sinking in your control area affects the qualified path.
    • A POS TDF means these tags make the loading on the victim path WORSE.
    • A NEG TDF means these tags make the loading on the victim path BETTER.
  • This screen is useful if an event is in the non-curtailment steps (steps 1-3) and an entity wants to see if they have tags coming up that may have to be curtailed.
red green black tdf column
Red/green/black TDF column

Warning or Highlight for Negative TDFs – TDFs in the USF Procedure Report are color coded (red, green, and black).

  • Red = Over the minimum threshold and must be dealt with immediately.
  • Green = These tags are helping the suffering path and should not be curtailed
  • Black = No action required
preload mw cap according to curtailment requirement
Preload MW Cap According To Curtailment Requirement
  • This feature gives the option to preload the MW Cap column for Off Path tags according to the curtailment requirements for each tag.
  • To use the new functionality, click on the icon next to the ‘Tag Adjustments’ header when looking at off-path tags in a USF Report. 
  • A menu will be displayed with an option to preload the MW Cap column or to reset the column. 
  • Since fractional adjustments are not allowed, the preloaded MW Cap is rounded down to the next whole number so as to assure that the total relief provided will be no less than the requirement. 
  • After preloading, the ability to modify the adjustments before confirmation will still be available.
dropdown path listing shows other paths and nwmt transactions affecting those paths
Dropdown Path Listing shows other paths and NWMT transactions affecting those paths

Path 20 aka Path C is affected by these NWMT Schedules

tdf study
TDF Study
  • Under ModelTransfer Distribution factor, you are able to study how much a schedule from source to sink affects a qualified path.
usf log
  • The log is useful to examine recent history:
    • Paths that have had trouble recently
    • Time of day to expect trouble
    • To determine how long events on this path may last
    • Determine what step of the plan was reached
    • Note also the TDF update date to let you know when OATI put in the latest TDFs from the WECC staff.
  • The TDF’s are calculated from Zone to Zone.
  • The Zone Lists cross reference from Zone Name to Zone Number.
zone lists
Zone Lists
  • Each zone has a name and a number.
  • Sources and sinks are assigned to zones
  • Tags do not contain zone information so this tables cross-references sources and sinks to zones.
websas examples
Websas Examples
  • Ex. 1: May 31, 2005 NWMT had post-event tags.
  • Ex. 2: Path 36 and 66 Event on May 19, 2005
    • Competing requests for relief
websas ex 1 may 31 2005
WEBSAS Ex 1 May 31, 2005
  • COI (Path 66) event at step 9
  • Path Limit = 3784 MW
  • Path Actual = 3798 MW, 14 MW OTC violation
  • Schedule Limit = 3519 MW, Accomodating 3784 – 3519 = 265 MW which is 7% of Path Limit
  • Schedules = 3288, which is 231 MW less than schedule limit
  • Total Unavailable to COI owners = 231 + 265 = 496 MW
ex 1 solution
Ex 1, Solution
  • Since Path Actual exceeds Path Limit by 14 MW and
  • On-path accomodation is over 7% (265 MW’s)
  • Off-path tags must be cut to get 15 MW relief
  • At the time the event was called:
    • BPA P01 PSE could provide 1.9 MW relief
    • SPP S1 PSE could provide 7.0 MW relief
    • TSPMTS PSE could provide 6.6 MW relief
    • NO relief required from NWMT
  • All WEBSAS agents should watch for post-event tags, however
ex 1 nwmt s part of solution
Ex 1, NWMT’s part of Solution
  • NWMT had 38 tags (36 Implemented tags at time event was called and 2 post-event tags); 4 implemented and 1 post affect COI.
  • 5 post/impl tags affected COI, 4 with +TDF and 1 with – TDF
  • TDF * scheduled MW’s for the 5 tags summed to +3.8 and -0.6 for net of +3.1
  • Curtail the + TDF tags to get 3.1 MW relief
ex 1 nwmt post impl tags
Ex 1 NWMT post/impl tags
  • POSTCHPD_AVA_NWMT .04*70 = 2.8
  • IMPLBPAT_BPAP_NWMT .05*12=.6
  • IMPLBPAT_BPAP_NWMT .05*5=.25
  • IMPLCHPD_REMC_NWMT .04*2=.1
  • IMPLIPC_IPC_NWMT -.02*30=-.6

Total = 2.8 + .3 = 3.1

ex 1 nwmt actions on may 31 05 didn t help
Ex 1 NWMT Actions on May 31, 05 didn’t help
  • Didn’t curtail the IMPLEMENTED tags using WEBSAS as seen in Floating Box part 2 & 3 (=0)
  • Didn’t curtail the post-event tags as seen in Floating Box part 1 (= - 2.8)
ex 1 what we should have done may 31 2005
Ex 1, What we should have done May 31, 2005
  • Use WEBSAS to curtail IMPLEMENTED tags for .3 MW relief (Box 2 & 3 = 0.3)
  • Use WEBSAS to curtail post-event tags for 2.8 MW relief (Box 1 = +2.8)
  • Total relief provided would be 3.1for cutting 89 MW’s of tags
may 31 2005 event floating box
May 31, 2005 Event Floating Box

Should have been +3.1

Should have been +2.8

Should have been 0.3

special tags affecting path 66
Special Tags affecting Path 66
  • If a schedule from AVA to NWMT is cut because it has a POS TDF for Path 66, be sure AVA doesn’t replace it with a tag equally as bad on path 66.
  • A list of generators with NEG TDF for Path 66 to NWMT may be handy.
  • NWMT must serve the load with tags not POSITIVELY affecting COI.
websas ex 2 path 36 66
WEBSAS Ex 2, Path 36 & 66
  • Path 36 should accommodate 77 MW (13%) and has only cut on-path schedules by 50 so they have 27 left to cut on-path. There were no off-path schedules to cut for path 36.
  • Path 66 had accomodated 154 MW (5%) but needed some help from NWMT.
ex 2 nwmt tags for path 66
Ex 2, NWMT tags for path 66
  • 1 post-event tags for 20 MW at 5% = 1 MW
  • 4 tags with POS TDF
    • BPAT_BPAP_NWMT 5% * 6 = 0.3
    • BPAT_BPAP_NWMT 5% * 20 = 1.0
    • BPAT_PSCMPS_NWMT 5% * 1 = 0.0
    • BPAT_PPLMS_NWMT 5% * 10 = 0.5
  • 1 tag with NEG TDF
    • IPCO_IPCM01_NWMT -2%*30 = -0.6
  • Total = 1.8 + 1 = 2.8 and with credit for IMPLEMENTED NEG TDF tag with -.6 affect, 2.8 - .6 = 2.2 MW relief from NWMT.
  • This shows we get credit for good tags that help reduce the path overloads.
nwmt total relief required
NWMT total relief required
  • 2.2 MW relief required
    • 1 MW post-event
    • 1.2 MW IMPLEMENTED tags
      • 1.8 POS TDF’s
      • -0.6 NEG TDF’s
ex 2 may 19 2005 nwmt actions
Ex 2 May 19, 2005: NWMT Actions
  • NWMT did not curtail 20 MW post event tag to get 1 MW relief
  • NWMT did not curtail 37 MW’s of IMPLEMENTED tags to get 1.2 MW relief
  • NWMT should have used WEBSAS to do both to get
    • Box 1 = 1
    • Box 2 = 1.2
may 19 2005 event floating box
May 19, 2005 Event Floating Box

Should have been 2.2

Should have been +1

Should have been 1.2

go forth and curtail

Go forth and curtail!

Please send comments and suggestions to the Unscheduled Flow Administrative Subcommittee exploder at the WECC