WECC Field Trial of the Balancing Authority ACE Limit by qwc99136

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									WECC Reliability-Based Control - Field Trial Plan
Performance Work Group – DRAFT

            WECC Field Trial of the Balancing Authority ACE Limit
            Under NERC Project 2007-18 Reliability-Based Control
The following points layout the framework and special considerations for implementing the
Reliability-Based Control (RBC) Field Trial (FT) in the WECC.

  1. FT Administration

   1.1.     The FT will be administered by the Performance Work Group (PWG), which will
            collect all data as required and produce all reports as deemed necessary. The PWG
            may ask for assistance from the NERC RBC Standard Drafting Team (SDT) in
            implementation or analysis.

   1.2.     It is the responsibility of the PWG to determine whether each Field Trial participant is
            accurately calculating the variables described in Appendix A and performing
            accordingly under the FT. The PWG will contact the FT participant if analysis of the
            participant data reveals inaccurate implementation of the necessary calculations or
            any discrepancies in data when compared to other FT participants.

   1.3.     On a monthly basis, the PWG will provide clock-minute data for each FT participant to
            the SDT. This data will be summarized so that the identity of each participant cannot
            be determined from the data provided. The PWG will provide a method to relate each
            Balancing Authority (BA) to their data submitted so as to follow up when issues arise.
            As defined in Appendix A, the clock-minute data provided to the SDT will include:
               1.3.1. Date-time (converted to Pacific time)
               1.3.2. ACE
               1.3.3. Frequency Error
               1.3.4. Actual Frequency
               1.3.5. Frequency Bias
               1.3.6. Scheduled Frequency
               1.3.7. BA ACE Limits, High and Low
               1.3.8. Minute count of ACE exceeding the limits
               1.3.9. Various quality codes
               1.3.10. Other fields as defined in Appendix A

   1.4.     To the extent the SDT requires analysis of ACE or other data not provided to the
            SDT, the PWG will assist the SDT as needed in a manner protecting the anonymity of
            the participants.

   1.5.     On a monthly basis, the PWG will provide its analysis of the FT as part of the SDT
            conference call with members of the NERC Resources Subcommittee, Operating
            Reliability Subcommittee, and Reliability Coordinator Working Group.

   1.6.     Prior to the FT, all BAs in WECC must be surveyed to accomplish the following:
               1.6.1. Inform the BAs of the planned FT
               1.6.2. Acquire the BAs commitment to participate in the FT
               1.6.3. Ask for an assessment of their capability to implement the FT including:
                       1.6.3.1. Will they need or do they intend to implement any EMS or logging
                                  changes?


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                       1.6.3.2. If so, when will the changes be implemented?
              1.6.4.    Ask whether the BA will participate (see 2.1) if mandatory participation is
                        not required.

   1.7.     Within the month prior to operation under the FT, the PWG will provide the RBC SDT
            the list of BAs that will participate in the FT in the subsequent month for addition to
            the list of BAs to be waived of compliance with NERC CPS2.

   1.8.     Upon receipt of the PWG list of BAs to begin operation under the FT, the chair of the
            SDT will provide documentation to the NERC Standards Committee, the NERC Vice
            President and Director of Standards, and the NERC Vice President and Director of
            Compliance, requesting that the BAs be added to the list of participating BAs waived
            of compliance to NERC CPS2 while operating under the FT. If waiver of compliance
            to NERC CPS2 is not received the FT will not be executed.


   1.9.     The PWG recommends the FT last approximately one year. Pending approval and
            implementation of the BA survey, workshops, and resolution of issues arising from
            such the PWG recommends executing the FT from March 1, 2010 through
            February 28, 2011. If these matters are delayed or otherwise not completed prior
            March 1, 2010, the FT should be correspondingly delayed. On a timetable
            commensurate with meeting schedules of the Operating Practices Subcommittee
            (OPS) and the Operating Committee in first quarter of 2011, the PWG with the SDT
            will analyze the available FT data, summarize their findings and produce a report with
            their recommendation to terminate the FT as planned or to extend it for a specified
            period.

                1.9.1. During the FT, if the PWG, SDT and the OC Chairs determine that
                     operation under the FT threatens reliability, they can call for an immediate
                     suspension of the FT for the Western Interconnection. In case of an early
                     termination of the FT, all BAs will be subject to compliance under CPS2.

   1.10. The PWG will establish criteria for evaluation of the FT prior to its execution. This
         criteria may include the following, as well as other criteria:
             1.10.1. The number of manual Time Error corrections
             1.10.2. Unscheduled Flow and the number of Unscheduled Flow Mitigation
                     procedures executed
             1.10.3. Magnitude of Accumulated NERC Inadvertent Interchange
             1.10.4. Magnitude of Accumulated Primary Inadvertent Interchange
             1.10.5. Frequency
             1.10.6. Path limits, Actual and Scheduled Flows on Defined Paths
             1.10.7. ADI transfers/schedules


   1.11. Any Balancing Authority may withdraw from the FT upon notification to the PWG of
         the date when it will cease operating under the FT and provide justification for
         withdrawal. Upon withdrawal the BA will be held responsible for compliance under
         CPS2.




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   1.12. The PWG or SDT may terminate participation of any BA in the FT, based on the BA’s
         performance in the FT or any reliability issue that may need to be addressed.

   1.13. When a BA ceases operation under the FT, the PWG will notify the SDT of the BA’s
         change in status. At that time the BA will be subject to compliance under CPS2.

   1.14. To support integrity in reported data, approved BAs will cease participation in the FT
         at the end of a calendar month, with CPS2 compliance beginning on the first day of
         the following month.

   1.15. A timeline of FT implementation and key dates is provided in Appendix C.

   1.16. As the BAL standards are drafted and revised during the FT, the PWG or SDT may at
         anytime change the field trial parameters such as frequency limits, transmission
         impact limits, monthly reporting or other parameters.

   1.17. Collection, analysis, reporting, and dissemination of BA FT data to the SDT could take
         a significant amount of time, possibly as much a staff-week per month or more,
         initially. (The SDT has offered to provide estimates of resource requirements as well
         as modifying the FT analysis tools for WECC. Any analysis of WECC-specific data
         (see below) will solely be a WECC responsibility). The PWG recommends that WECC
         identify or acquire and commit such a resource.

  2. BA Participation in and Execution of the FT

   2.1.     It is recommended that all BAs with a 2009 Estimated Peak Load greater than 500
            MW t participate in the FT. It is recommended that Generation-only BAs with
            Maximum Generation Capacity greater than 500 MW participate in the FT. BAs with a
            2009 Estimated Peak Load or Maximum Generation Capacity (for Generation-only
            BAs) of 500 MW or less are also encouraged to participate. .

   2.2.     A variety of data related to the preceding criteria will need to be collected. Appendix A
            details data collection and reporting requirements of BAs participating in the FT.

                2.2.1. The data collected will include, but is not limited to, the following: NERC
                     ACE, Control ACE, Frequency Error, Frequency Bias, Actual Frequency,
                     Scheduled Frequency, ADI Adjustment, and CPS1.

                2.2.2. If the BA considers any of the submitted data to be confidential, then the
                     BA must mark the data as such. See NERC Rules of Procedure Section
                     1500. If confidential information is submitted then the PWG will use best
                     efforts to maintain the confidentiality of that data, but such efforts will not
                     preclude the PWG Members from administering the FT.


   2.3.     During the FT, the BAL-001 CPS2 requirement will be waived for participating BAs;
            however, the requirement for participants to calculate and report CPS2 performance
            for informational purposes will remain in effect.

   2.4.     For initial implementation of the FT, and until otherwise instructed by the PWG,
            participating BAs will implement an ACE “cap” set at 2*L10 to limit the transmission


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            impact of unbalanced operation. Participating BAs will operate in a manner so that
            ACE does not exceed either the applicable BA ACE Limit (BAALlow/high), or the
            applicable ACE cap, or both, for more than 30 consecutive clock-minutes.

   2.5.     The intent of the RBC Standard (BAL-007) is to allow a wider range of operation
            without negatively impacting reliability, while controlling resources more tightly at
            times to ensure that the BA’s clock-minute ACE does not exceed the Balancing
            Authority ACE Limit for more than 30 consecutive clock-minutes. BAs are allowed and
            encouraged to manage their AGC control status. To that intent, each BA:
               2.5.1. Will control resources to return ACE to within the BAALlow/high limits per the
                       draft standard or at the direction of the Reliability Coordinator or the
                       PWG/SDT.
               2.5.2. Will be asked in the BA survey to provide its intended strategy for
                       complying with BAL-007 and what modifications, if any, the BA will
                       implement to its EMS.
               2.5.3. Must continue to calculate ACE, CPS1, CPS2, etc., and provide the
                       calculations to appropriate logging/reporting functions for that BA.
                       Confirmation that calculation/logging will continue and that BA data and
                       reporting requirements can be met during the FT will be part of the BA
                       survey.

   2.6.     The basic control objective for the RBC is articulated in draft BAL-007. BAs will need
            to control resources to meet that objective. This can be implemented basically in any
            of a number or combination of ways, some of which are described below. BA’s should
            be able to easily switch back to CPS2 controls under the existing NERC standard due
            to a possible suspension of the FT for reliability reasons.
              2.6.1.   Using “standard” EMS functionality, calculate BAALlow/high and the high/low
                       ACE “cap,” and provide an alarm to the Operator when the clock-minute
                       average of ACE has exceeded an appropriate limit (See Appendix A –
                       Calculation of Variables).
              2.6.2.   Examine the AGC systems and adjust various tuning parameters — such
                       as deadbands, time constants, and limits — to achieve, as closely as
                       possible, the RBC objective.
              2.6.3.   Most EMS’ don’t have frequency-based tuning parameters and such tuning
                       is only approximate over a limited frequency band. BAs will need to
                       monitor ACE near the BAAL, which does vary with frequency.
              2.6.4.   Implement one of the user interfaces provided for by the SDT on the
                       NERC Web site under Project 2007-18 Reliability-Based Control (see
                       Appendix D).

            Under any approach taken, a BA must return ACE to within the BAALlow/high before
            exceeding a period of 30 consecutive clock-minutes, as prescribed by the standard.
            The steps to do so are at the discretion of the BA and can be manual or automatic.
   2.7.     Prior to the commencement of the FT, participating BAs will confirm to the PWG that
            their Operators have been trained in the specifics of the FT implementation at that
            BA.

  3. Reliability Coordinator Participation in the FT




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   3.1.     The Reliability Coordinator will have authority, as per NERC Reliability Standards, to
            direct participating BAs to take corrective action on the BA’s system if the Reliability
            Coordinator experiences problems it believes may be attributed to the BA operations
            under the FT.
   3.2.     Upon notification by the Reliability Coordinator of such a directive, the BA will execute
            accordingly and contact the PWG if it believes the directive is the result of
            participation in the FT. The PWG, in concert with the RBC SDT, may convene a
            conference call to assess the situation and identify corrective measures. The
            Reliability Coordinator will be required, upon request, to participate in such
            conference calls.

   3.3.     In the event of abnormal interconnection frequency, Appendix B proposes actions that
            may be taken by the Reliability Coordinator.




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                  WECC Reliability Based Control Field Trial
                                       Appendix A
                          FT Data Submittal Format and Calculations

For analysis of Control Performance Measure and Balancing Authority ACE Limit (“BAAL”)
performance under the FT, clock-minute data will be provided in monthly files under the
following Comma-Separated-Variable (“CSV”) format:

BA, Date, Time, TimeZone, ACE, FreqError, FreqBias, ActFreq, SchedFreq, AQC, FQC, CACE,
ADIAdj,BAAL_Low, MinCtLow, BAAL_High, MinCtHigh, CPS1, ACPS1, ATLlow, MinCtLow2,
ATLhigh, MinCtHigh2, LowLimitCt, HighLimitCt <EOL>

Field Name                          Description/Type
BA                                  BA acronym in NERC Registry (up to 4 characters)
Date                                Date format (MM/DD/YY),
Time                                24-hour time format (hh:mm),

TimeZone                            3-character time-zone abbreviation (MST, MDT, PST,
                                    PDT, etc)

ACE**                               Clock-minute average Area Control Error (MW)
(REAL)                              used for NERC reports (NERC ACE)
                                    (minimum of 1 digit to right of decimal point)

FreqError                           Clock-minute average Frequency Error (Hz) Frequency
Error is (REAL)                            equal to Actual Frequency minus Scheduled
Frequency.
                                    (minimum of four digits to right of decimal point)

FreqBias                            Clock-minute average Frequency Bias (MW/0.1 Hz)
(REAL)                              (same precision as implemented in EMS)

ActFreq                             Clock-minute average Actual Frequency (Hz)
(REAL)                              (minimum of four digits to right of decimal point)

SchedFreq                           Clock-minute average Scheduled Frequency (Hz)
(REAL)                              (minimum of two digits to right of decimal point)

AQC*                                ACE Quality Code (0=valid data, 1=bad data)
(INTEGER)

FQC*                                Frequency Quality Code (0=valid data, 1=bad data)
(INTEGER)

CACE**                              Clock-minute average Area Control Error (MW)
(REAL)                              used for control of generating units (Control ACE)
                                    (minimum of 1 digit to right of decimal point)




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ADIAdj**                              For those BAs participating in ADI, the clock-minute
(REAL)                                average of the ACE adjustment value received from ADI.
                                      Otherwise, 0.0
                                      (minimum of 1 digit to right of decimal point)

BAAL_Low                              BAALLow (MW)
(REAL)                                (minimum of 1 digit to right of decimal point)

MinCtLow                              Count of the consecutive minutes of negative ACE <
(INTEGER)                             BAALLow when Actual Frequency is < 60 Hz.

BAAL_High                             BAALHigh (MW)
(REAL)                                (minimum of 1 digit to right of decimal point)

MinCtHigh                             Count of the consecutive minutes of positive ACE >
(INTEGER)                             BAALHigh when Actual Frequency > 60 Hz.

CPS1                                  Clock-Minute Calculation of CPS1 under BAL-001
(REAL)                                (minimum of 1 digit to right of decimal point)

ACPS1                                         Clock-Minute Adjusted CPS1 as described in
Attachment F
(REAL)                                (minimum of 1 digit to right of decimal point)

ATLlow                                ATLLow (MW) - Transmission-based ACE low limit
(REAL)                                (minimum of 1 digit to right of decimal point)

MinCtLow2                             Count of the consecutive minutes of negative ACE <
(INTEGER)                             ATLLow.

ATLhigh                               ATLHigh (MW) – Transmission-based ACE high limit
(REAL)                                (minimum of 1 digit to right of decimal point)

MinCtHigh2                            Count of the consecutive minutes of positive ACE >
(INTEGER)                             ATLHigh.

LowLimitCt                            Count of the consecutive minutes of negative ACE <
(INTEGER)                             BAALLow or ATLLow.

HighLimitCt                           Count of the consecutive minutes of positive ACE >
(INTEGER)                             BAALHigh or ATLHigh.

*If no quality code is available, then write 0 for all records. Ideally, the user should have the
capability to update the quality code for the ACE and Frequency with each sample to flag
whether that sample represents good or bad data. If over 50% of the samples of ACE for a
given period have bad data, then AQC for that period should be flagged as "bad" for the ACE
represented. If less than 50% of the samples represent bad data, then AQC for the period
should be flagged as "good" using only the good samples of ACE for that period. Likewise, if
over 50% of the samples of frequency for a given period have bad data, then FQC for that
period should be flagged as "bad" for the frequency represented. If less than 50% of the


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samples represent bad data, then FQC for that period should be flagged as "good" using only
the good samples of frequency for that period.

** ACE is the clock-minute ACE used in calculating CPS1 performance. ACE is typically referred
to as “NERC ACE.” CACE is the value used for generation control calculated per BAL-004-
WECC-01, typically referred to as “Control ACE.” BAs participating in ACE Diversity Interchange
(ADI) will include the additional term ”ADIAdj” in both of these ACE values. “ADIAdj” is the clock-
minute average of the Pseudo-Tie included in ACE for the dynamic transfer(s) under ADI.

Example CSV records:
BA,11/21/2004,10:00,EST, -10.2,-0.0080,-90.0,59.9920,60.00,0,0,-12.2,0,-281.3,0,0.0,0,. .
BA,11/21/2004,10:01,EST, -2.5,-0.0100,-85.0,59.9900,60.00,0,0,-3.5,0,-212.5,0,0.0,0,. .
BA,11/21/2004,10:02,EST,   1.6,-0.0070,-80.0,59.9930,60.00,0,0,0.6,0,-285.7,0,0.0,0,. .
BA,11/21/2004,10:03,EST,-309.0,-0.0370,-80.0,59.9630,60.00,0,0,-310.0,0,-54.1,1,0.0,0,. .
BA,11/21/2004,10:04,EST,-310.4,-0.0420,-80.0,59.9580,60.00,0,0,-311.4,0,-47.6,2,0.0,0,. .
BA,11/21/2004,10:05,EST,-312.5,-0.0540,-80.0,59.9460,60.00,0,0,-313.5,0,-37.0,3,0.0,0,. .


Note that the fourth row of data represents the first clock-minute record where the ACE of -
309.0 MW was outside the BAAL_Low boundary of -54.1 MW. As ACE remained outside the
calculated BAAL boundary for the next two clock-minutes, "MinCtLow" was incremented for
each record.

Note that column headings are not to be provided in the monthly CSV files.

Monthly File Naming Convention
Data shall be provided to the PWG on a monthly basis no later than the tenth working day of the
month using the following naming convention:

YYYYMM_BA.CSV, where YYYY is the four-digit year, MM is the two-digit month (01-12), and
BA is the BA acronym in NERC Registry (up to 4 characters). If the WECC staff, in conjunction
with PWG will perform the FT analysis, the staff resource will proceed according to Appendix E.

If the SDT will perform the FT analysis, or if the SDT will perform a parallel analysis to
corroborate the WECC PWG analysis, the data files will be forwarded to the SDT. To maintain
anonymity of the BA to the SDT (as CPS data is provided per the FT), the PWG will assign a
number to each participating BA. To forward data to the SDT, the PWG (or WECC staff) will
modify the file (saving the original) replacing the BA acronym with BAnn, where nn is the
number assigned the BA. This modified file will be saved by the following name:
YYYYMM_BAnn.CSV for delivery to the SDT. For example, August 2009 data for AZPS if
AZPS has been assigned the number 03, will have the file name of 200908_APS.CSV when
delivered to the PWG and 200908_BA03 when delivered to the RBC SDT. Any other BA data
provided to the SDT will include the assigned BA number rather than BA acronym.

Once the data has been stored into the monthly CSV file, the user should then compress the
file, typically 3-4 MB, into a “ZIP” file with the same naming convention (YYYYMM_BA(or
BAnn).ZIP). Monthly data is to be provided via email no later than the tenth working day of the
month rbcreports@wecc.biz and the modified files will be forwarded to the chair of the SDT by
the fifteenth working day of the month.

Questions should be directed rbcreports@wecc.biz




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Calculation of Variables

The Balancing Authority ACE Limit (“BAAL”) should be calculated from the clock-minute
averages of the data as follows:


FTLLow = 59.932 Hz
FTLHigh= 60.068 Hz

ATLLow = -2*(BA CPS2 L10)                   Transmission-based ACE limit set for an interim period
ATLHigh= 2*(BA CPS2 L10)                    at two times the BA’s L10 as recommended by the
                                            WECC PWG.
X = Actual Frequency – 60 Hz
(note: during time-error corrections, this variable is not equal to the Frequency Error which is
always the difference of Actual Frequency minus Scheduled Frequency)

If X <= 0 then
   BAALLow = (-10*Frequency Bias*(FTLLow -60 Hz)2)/(X - 0.000000001)
Else
   BAALLow = 0.0
End If                                                               Needed to prevent division
                                                                            error when X = 0 but will
If X > 0 then                                                               be insignificant in the
                                                                            calculation when X < 0
   BAALHigh = (-10*Frequency Bias*(FTLHigh-60 Hz)2)/(X)
Else
   BAALHigh = 0.0
End If

The logic for the clock-minute counters (initialized at zero) would then use the logic:

If BAALLow < 0 then
   If ACE < BAALLow then
      MinCtLow = MinCtLow + 1
   Else
      MinCtLow = 0
   End If
   MinCtHigh = 0
End If

If BAALHigh > 0 then
   If ACE > BAALHigh then
      MinCtHigh = MinCtHigh + 1
   Else
      MinCtHigh = 0
   End If
   MinCtLow = 0
End If

If ACE < ATLLow then
   MinCtLow2 = MinCtLow2 + 1
Else


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  MinCtLow2 = 0
End If

If ACE > ATLHigh then
   MinCtHigh2 = MinCtHigh2 + 1
Else
   MinCtHigh = 0
End If

If (MinCtLow + MinCtLow2) > 0 then
   LowLimitCt = LowLimitCt + 1
Else
   LowLimitCt = 0
End If

If (MinCtHigh + MinCtHigh2) > 0 then
   HighLimitCt = HighLimitCt + 1
Else
   HighLimitCt = 0
End If


Monthly Analysis of Events:
On a monthly basis, each Balancing Authority will review its performance for the prior month
and identify any periods where the ACE exceeded the low BAAL (“BAALLow”) or the high BAAL
(“BAALHigh”) for more than ten consecutive clock-minutes.1 To help the RBCSDT gain a better
understanding of the circumstances that all Balancing Authorities may be faced while operating
under BAL-007, each Balancing Authority will provide a brief explanation to the PWG of the
circumstances related to any periods where the duration of consecutive clock-minutes exceeded
twenty minutes. In the event that no period exceeded twenty minutes in the prior month, but the
longest duration exceeded ten minutes, the Balancing Authority will provide a brief explanation
of the circumstances related to that event.

The brief explanations provided above will be for PWG and RBCSDT use and should be
provided by the tenth working day following the operating month. In the event that the Balancing
Authority exceeds 30 consecutive clock-minutes in restoring its ACE within the BAAL, the
RBCSDT will request the Balancing Authority to provide a detailed account of the associated
event to the Chair of the RBCSDT so that it can be reviewed by the RBCSDT and provided to
the Balancing Authority’s Regional Entity for informational purposes only.




1
 During the interim period as described in 2.4 of the WECC Field Trial document, while the Balancing
Authority is operating in a manner not to exceed either set of bounds (the BAAL or the ACE “cap”) for
more than 30 consecutive clock-minutes, the BA will also report on similar periods reviewing MinCtLow2,
MinCtHigh2, LowLimitCt and HighLimitCt as calculated in this Attachment A.


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                      WECC Reliability-Based Control Field Trial
                                            Appendix B
                                         RC Monitoring
           Proposed Frequency Monitoring and Response Process
                      for the Western Interconnection
Reliability Coordinators (RC) Short-Term Triggers and Actions
NOTES:
1) This document contains suggested actions of the RC which may be implemented in addition
    to any other actions the RC deems necessary to ensure the reliable operation of the
    Interconnection.
2) If the frequency exceeds the Frequency Relay Limit (FRL) or Frequency Abnormal Limit
    (FAL) high or low, then immediate action is required. The Frequency Trigger Limit (FTL)
    represents the initial frequency where the reliability coordinators should issue directives, if
    necessary.1
3) RCs should log any unusual frequency event.
4) The WECC Performance Work Group (PWG) shall retrieve and review all events logged by
    the reliability coordinators regarding actions taken for exceeding these limits.

      Frequency Trigger                      Measure                           Actions
60.5 Hz                          FRL High                          1,4
60.2 Hz                          FAL High                          1,3
60.068 Hz (if >10 minutes)       FTL High                          1,2
60.068 Hz (if >5 minutes         FTL High                          1
59.932 Hz (if >5 minutes)        FTL Low                           1
59.932 Hz (if >10 minutes)       FTL Low                           1,2
59.8 Hz                          FAL Low                           1,3
59.50 Hz                         FRL Low                           1,4

Actions
1. The RC should:
      Monitor the Balancing Authorities (BAs) within its RC area to identify if any BAs have an
      Area Control Error (ACE) beyond the limits established for the RBC FT.

2. The RC should:
      Request, or direct, if necessary, all BAs within their RC area that have an ACE beyond
      the limits established for the RBC FT to take corrective action as required under the FT.
      Log event details and corrective actions. If the cause of the event is not known, then
      survey all BAs within the RC area for information and data.

3.   The RC should:
       Advise, or direct, if necessary, all BAs that have an ACE that is contributing to the
       frequency deviation to return ACE to an acceptable limit.
       Log event details and corrective actions. If the cause of the event is not known, then
       survey all BAs within the RC area for information and data.

4. The RC should:
      Evaluate and determine if the RC area and all BA areas within the RC area are still
      interconnected.


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         Provide information to assist emergency actions.
         Log event details and corrective actions. If the cause of the event is not known, then
         survey all BAs within the RC area for information and data.


Longer-Term Triggers and Benchmarks (Reliability Coordinators)
 Frequency Deviation       Measure                         Actions
+/- 31 mHz                   Rolling 60-minute    RCs shall log event details and corrective actions. If the
                             Average              cause of the event is not known, then survey all BAs within
                                                  the RC area for information and data.
75 mHz                       Change over 10       RCs shall archive their BAs’ corresponding ACE changes to
                             seconds (future-in   capture unit trips for frequency response benchmarking.
                             CERTS)               RCs shall log event details and corrective actions. If the
                                                  cause of the event is not known, then survey all BAs within
                                                  the RC area for information and data.



Longer-Term Triggers and Benchmarks (Performance Work Group)
 Frequency Deviation       Measure                      Actions
    From Schedule
+/- 31 mHz                   Rolling 60-minute    PWG shall perform an AIE Survey if the problem is not
                             Average              known. If the problem is known, then survey entities
                                                  involved to determine any lessons. PWG shall record and
                                                  maintain the results for analysis and historical trending.
20 mHz                       Daily RMS one-       PWG shall evaluate daily data to determine if AIE survey is
                             minute average       justified for significant hour(s). PWG shall record and
                                                  maintain the results for analysis and historical trending.
16.8 mHz                     Weekly RMS one-      PWG shall evaluate week’s data and events in order to
                             minute average       determine the underlying cause. PWG shall record and
                                                  maintain results for analysis and historical trending.
75 mHz                       Change over 10       PWG shall review BAs’ corresponding event data. For
                             seconds (future-in   events exceeding 150 mHz, PWG shall perform a
                             CERTS)               Frequency Response survey.




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                   WECC Reliability Based Control Field Trial
                                          Appendix C
                                   FT TimeLine and Key Dates

OVERVIEW

The FT will be coordinated by the RBCSDT with the PWG in the following phases:

June 2009
   At the June meeting, the OC approved the following motion on the RBC FT implementation
   plan:
           1. The OC endorses a goal of implementing a Reliability-Based Control Field Trial
              during the first quarter of 2010.
           2. WECC will sponsor a workshop prior to August 15, 2009, to discuss RBC field
              trial implementation issues.

            3. The OPS will modify the RBC Field Trial as required, based on BA and RC input.
            4. The OC will consider approval of the RBC Field Trial plan at its October 2009
               meeting.


July 2009
   1. PWG administers the BA survey to assess the readiness of BAs subject to or
       participating in the FT to execute the FT and collect and report data as required.
   2. WECC designates staff resource to perform data collection and analysis with guidance
       and tools provided by RBC SDT.

August 2009
  1. BAs return completed surveys to WECC
  2. PWG conducts workshop on FT on August 13.

September 2009
   1. PWG issues revised FT document reflecting survey and workshop results
   2. PWG posts the FT document for 30 day comment period prior to OC approval
   3. BAs begin preparing to implement the FT

October 2009
   1. OC approves the FT plan and document
   2. OC posts the FT plan for WECC Board approval

December 2009
   WECC Board approves the FT plan

January 2010
   1. PWG conducts final FT workshop, conference call or such as needed requested by BAs
      and/or the OC
   2. Reliability Coordinators certify that they are ready to fulfill the requirements of Appendix
      B in execution of the FT.

February 2010



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   1. BAs will confirm that they are ready to commence operations under the FT on 3/1/2010
      and will forward two weeks of January FT data to PWG/WECC staff for evaluation. The
      PWG/RBCSDT will verify that BAs have met the requirements for participation in the FT
      as described in this document and that the Reliability Coordinator is aware of their
      participation.
   2. RC will certify that all participating BAs are providing all the data necessary
   3. PWG will announce readiness of all BAs to execute FT and commencement of the FT on
      March 1, 2010.
   4. PWG will forward list of participating BAs to the SDT to issue the CPS2 compliance
      waiver.

March 2010
   1. At mid-month (two weeks) BAs will submit data to PWG for the first two weeks of the FT.
   2. The PWG/RBC SDT will review the first two weeks of operation under the FT at its
      monthly review (see Appendix E) of operations in the latter part of March 2010 and will
      gather input from the NERC Resources Subcommittee, Operating Reliability
      Subcommittee and Reliability Coordinator Working Group to determine if there were any
      reliability issues attributed to the FT that need to be considered by the PWG/RBCSDT.

May 2010-March 2011
   1. The PWG/RBC SDT will review the previous month’s operation under the FT at its
       monthly review (see Appendix E) of operations and will gather input from the NERC
       Resources Subcommittee, Operating Reliability Subcommittee and Reliability
       Coordinator Working Group to determine if there were any reliability issues attributed to
       the FT that need to be considered by the PWG/RBCSDT
   2. During the conference call, the PWG/RBCSDT will ask for feedback from the BAs and
       the RC, including suggestions on how the FT can be enhanced.
   3. Based on the data and feedback provided back to the PWG/RBCSDT, among other
       items, the PWG/RBCSDT will determine if any actions are needed with regards to the
       FT.

January 2011 – March 2011
   1. On a timetable commensurate with meeting schedules of the Operating Practices
      Subcommittee (OPS) and the Operating Committee, the PWG with the SDT will analyze
      the available FT data, summarize their findings and produce a report with their
      recommendation to terminate the FT as planned or to extend it for a specified period.
   2. The OPS will review the PWG report, add their own observations and conclusions, and
      endorse or challenge the PWG recommendation.
   3. The OC will review the PWG report and recommendations as well as the OPS
      recommendations, and order the termination of FT as planned or the continuation of the
      FT for a specified period.
   4. The termination or continuation of the FT will be communicated to the SDT for update of
      the list of BAs waived of CPS2 compliance.




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                               WECC Reliability Based Control Field Trial
                                                              Appendix D
                                                         BA FT Monitoring Tools

CPS1 is a calculation for control performance that considers Balancing Authority operation at all
times to Scheduled Frequency. During fast or slow time-error corrections, the CPS1 curves shift
in a manner symmetric about the Scheduled Frequency, as illustrated in Figures 1 and 2.

  BA          -50   MW/0.1 Hz
                    Frequency Bias                             CPS1 and BAAL
       200

                                                                                                                    Figure 1


       100
  MW




          0




       -100




       -200
           59.9        59.92         59.94       59.96      59.98         60          60.02      60.04      60.06    60.08     60.1
                                                                     Frequency (Hz)

                                                   BAAL_High        BAAL_Low      CPS1 Bound at 60 Hz SF




  BA          -50   MW/0.1 Hz
                    Frequency Bias           CPS1 and BAAL at 59.98 Hz Scheduled Frequency
       200

                                                                                                                    Figure 2


       100
  MW




          0




       -100




       -200
           59.9        59.92         59.94       59.96      59.98         60          60.02     60.04       60.06    60.08     60.1
                                                                     Frequency (Hz)

                                                 BAAL_Low       BAAL_High       CPS1 Bound at 59.98 Hz SF




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The Balancing Authority ACE Limit (“BAAL”) was developed “from the ground up”, considering
the targeted research and development of Interconnection-specific Frequency Relay Limits,
Frequency Abnormal Limits, and Frequency Trigger Limits. As the BAAL calculation is not a
function of the Scheduled Frequency, its associated curves do not shift in a manner similar to
CPS1, rather the limits remain symmetric about 60 Hz. as illustrated in Figures 1 and 2.

Though good performance in the long term under CPS1 is based upon control about the
Scheduled Frequency, good performance in real-time under the BAAL is based also upon
control in support of the Interconnection frequency and taking action to limit the duration of
operating outside a variable bound that gets “tighter” as Actual Frequency deviates further from
60 Hz.

One type of display used to monitor when ACE exceeds the BAAL is provided below. The chart
tracks the number of consecutive clock-minutes that ACE exceeds the BAAL along with
displaying clock-minute ACE in relation to the clock-minute Actual Frequency.

                                                                                   Figure 3




The screen above is from an Excel worksheet that brings in data from a PI server (real-time and
historic data) to display the last 30 clock-minutes of ACE where the color and size of the dots
reflect the length of time passed. The Excel file is available on the NERC Reliability-based
Control website along with instructions for implementation with PI DataLink. As the duration of
ACE exceeding the BAAL is a critical aspect of BAL-007, Balancing Authorities may prefer to


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trend a value as a function of time similar to other operator interfaces where time is displayed on
the X or Y axis, as provided below.

In Western Interconnection, NERC CPS1 is calculated as follows:

CPS1 = (2-(ACE*Frequency Error)/(-10*Frequency Bias*0.0228*0.0228))*100
Note: clock-minute average values must be used for all variables

In addition to calculating real-time performance under BAL-007 by comparing the clock-minute
value of ACE to the calculated clock-minute value of the BAAL, the Balancing Authority can also
monitor an adjusted version of the NERC CPS1 calculation that is not dependent upon
Scheduled Frequency and referred to in this document as “ACPS1”. In the ACPS1 calculation
below, Frequency Error is replaced with the term “(Actual Frequency – 60)”.

ACPS1 = (2-(ACE*(Actual Frequency - 60))/(-10*Frequency Bias*0.0228*0.0228))*100
Note: clock-minute average values must be used for all variables
Note: when Scheduled Frequency = 60 Hz, the calculations of CPS1 and ACPS1 are identical

The BAAL calculation provided in Appendix A shows that BAAL varies as a function of the
Actual Frequency. By substituting BAAL for ACE in the ACPS1 calculation for a given value of
Actual Frequency, one can determine that ACE exceeds the BAAL when ACPS1 is worse than
approximately minus -689.5% for any Balancing Authority in the Western Interconnection based
upon a Frequency Trigger Limit set at epsilon1 multiplied by three (3). This information is useful
in that the operator can monitor its performance against a bound that remains fixed with the
value being monitored (ACPS1) being a function of ACE and Actual Frequency.




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                                                                                     Figure 4




 BAAL Exceeded where
 ACPS1< -689.5%




In the display above, the dotted line in the chart to the right represents the CPS1 calculation and
the yellow line represents the ACPS1 calculation. When Scheduled Frequency = 60 Hz, the
values are identical; however, during times of fast or slow time-error correction, the curves will
be different, requiring the operator to monitor operation to the long-term goal of averaging above
100% for CPS1, but also take action when the yellow line drops below -689.5% ACPS1
reflecting when the BAAL has been exceeded. The chart displayed can be selected from the
same Excel worksheet as the prior display available on the NERC Reliability-based Control
website.




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                     WECC Reliability Based Control Field Trial
                                          Appendix E
                                   Monthly Review Procedure

By the tenth working day of each month, the participating Balancing Authorities provide the
clock-minute data for the prior operating month to the PWG as described in Appendix A. If data
files are to be forwarded to the SDT, they will be sent to the SDT by the fifteenth working day of
the month.
The clock-minute data for each Balancing Authority will be imported into a database where all
records will be converted to GMT and time-aligned based upon the clock-minute Actual
Frequency data.
The queries shall provide the following:
   1) All clock-minutes when FTLLow was exceeded and
            a. Scheduled Frequency = 59.98 Hz
            b. Scheduled Frequency = 60.00 Hz
            c. Scheduled Frequency = 60.02 Hz

   2) All clock-minutes when FTLHigh was exceeded and
            a. Scheduled Frequency = 59.98 Hz
            b. Scheduled Frequency = 60.00 Hz
            c. Scheduled Frequency = 60.02 Hz

   3) All clock-minutes where FTLLow was exceeded, Scheduled Frequency = 59.98 Hz and
      Frequency Error was above -0.05 Hz.
   4) All clock-minutes where FTLHigh was exceeded, Scheduled Frequency = 60.05 Hz and
      Frequency Error was below 0.05 Hz.
   5) The maximum number of clock-minutes that FTLLow was exceeded for the month
   6) The maximum number of clock-minutes that FTLHigh was exceeded for the month
   7) All clock-minutes where BAALLow was exceeded for each Balancing Authority
   8) All clock-minutes where BAALHigh was exceeded for each Balancing Authority
   9) The maximum number of clock-minutes that each Balancing Authority exceeded
      BAALLow
   10) The maximum number of clock-minutes that each Balancing Authority exceeded
       BAALHigh
   11) View of all Balancing Authorities for each clock-minute for comparison of
            a.   Actual Frequency
            b.   Scheduled Frequency
            c.   ACE
            d.   Minute Counts for BAALLow or BAALHigh > 0
            e.   CPS1
            f.   ACPS1 (as described in Appendix D)




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For the duration of the period that transmission-based limits of two times L10 are used to limit
ACE even when in support of the Interconnection frequency, the following information will also
be gathered:
The queries shall provide the following:
   1) All clock-minutes where ATLLow was exceeded for each Balancing Authority
   2) All clock-minutes where ATLHigh was exceeded for each Balancing Authority
   3) The maximum number of clock-minutes that each Balancing Authority exceeded ATLLow
   4) The maximum number of clock-minutes that each Balancing Authority exceeded ATLHigh
   5) The maximum LowLimitCt for each Balancing Authority
   6) The maximum HighLimitCt for each Balancing Authority




10/7/2009                                                                                 Page 20

								
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