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Individual or group.  (17 Responses)
Name  (6 Responses)
Organization  (6 Responses)
Group Name  (11 Responses)
Lead Contact  (11 Responses)
Contact Organization  (11 Responses)
Question 1  (13 Responses)
Question 1 Comments  (17 Responses)
Question 2  (13 Responses)
Question 2 Comments  (17 Responses)
Question 3  (16 Responses)
Question 3 Comments  (17 Responses)
Question 4  (13 Responses)
Question 4 Comments  (17 Responses)
Question 5  (0 Responses)
Question 5 Comments  (17 Responses)
 
Individual
Sirajul Chowdhury
California ISO
Yes
 
Yes
 
Yes
 
No
I proposed to make BATL sensitive Path dynamic limit(COI for example), Derate and outage.
Devlop complience tool to identify offending BA who is not taking mitigation action in timely manner
Individual
Robert Blohm
Consultant
Yes
This concept of “maximum (allowed) contribution” metering-error threshold is the same as “minimum ACE” which is confused with “minimum BATL” in question 2 below.
No
In my understanding this question confuses “minimum ACE” with “value a BATL should not become smaller than” by switching between these terms while proposing setting minimum BATL equal to L10. This question is about “minimum BATL”, not “minimum ACE” which is covered as “threshold” ACE equal to 0.5% metering error in the preceding question 1. “Minimum BATL” should indeed be the same as “minimum ACE”, namely the “minimum ACE” set as “threshold” ACE equal to 0.5% metering error in question 1. A “minimum BATL” set equal to any larger value, such as L10, is dysfunctional and unfair. A fixed minimum BATL equal to L10 guarantees that any BA currently in compliance with CPS2 will not exceed the BATL, making the BATL not more onerous to the BA than CPS2 is. But this is a “one-sided pass” in favor of the BA and against the Interconnection and is therefore not justified technically or equitably. The BATL binds/constrains only when there is congestion. Therefore, when there is no congestion the BATL is already less onerous on both the BA and the Interconnection than is CPS2 which applies regardless of whether or not there is congestion. Whenever there is congestion however, a “minimum BATL” that is set outside “minimum ACE” provides an additional benefit to the BA, but at the expense of the Interconnection which is prevented from relieving congestion down to the minimum ACE. Basically the BA is afforded thereby the unfair and unreliable “added benefit”/“bonus”/“protection”/”guarantee” of never having to change current operating practice of compliance to CPS2 in order to comply with BATLs. The BA is thereby offered all the added convenience of BATL (when there’s no congestion) and none of the added inconvenience (whenever there is congestion)—all “one way”, all benefit and no cost! Accordingly, setting “minimum BATL” equal to L10 instead of equal to “minimum ACE” is an unnecessary “political bargaining” concession aimed at buying extra support for BATLs from a BA at the expense of the Interconnection and is, therefore, not technically justified, especially because it harms Interconnection reliability in the form of congestion management. In direct answer to the question, therefore, the “technically based method for eliminating” L10 is to (a) properly/clearly use terminology by identifying “minimum BATL” as identical to the “minimum ACE” 0.5% technically-justified metering error threshold set in question 1, while (b) recognizing that no technical justification has been given for setting “minimum ACE” equal to L10 , only a political justification as “a bound comparable to present requirements” in the wording of this very question. “Comparable” for what purpose? For the operating convenience of maintaining existing practice, not for technically improved reliability, in effect a bound no worse than what we currently have but certainly not better when the time comes to use it! That is politics, not technical excellence. L10 is also technically irrelevant: it (a) is irrelevant to congestion management, and (b) is a frequency-based limit applied to a ten-minute average of control error in furtherance of a very incomplete, commercially useful but reliability irrelevant technique of economically-efficient control on the sole basis of saving wear-&-tear by ignoring one-minute-average deviations and responding only to ten-minute-average deviations. In the wake of the BP disaster, NERC would do well to dispense with the last vestige of that narrow-band concept in setting reliability standards.
Yes
 
Yes
Concept correction: there is no such thing as "congestion risk" as expressed in this question and in the documentation accompanying this request for comments. There is "congestion". "Risk" is a technical term with precise mathematical definition and informal use of the term should be avoided especially as it can hamper proper deployment of appropriate mathematical methods.
I think this “ACE Distribution Factors” methodology of assigning BATLs is the best thing since sliced bread. However, there are a number of due-diligence issues as follows. 1. The “recent experiment with existing TDFs” together with its “Experimental Results” should be reported in full detail. Merely mentioning the results is not transparent. 2. There are several mistakes in the “Calculating ACE Distribution Factors” supporting this comment form: 2.1 There is a contradiction in the indexing of Sigma in equations (11) and (24): when Y = 1, both Z = 1 and Z not= 1 and, when Y = N, both Z = N and Z not= N. So, Z = 1 and Z = N should be removed from the indexing of Sigma in equations (11) and (24). 2.2 The equation for Beta-sub-X should be removed from the definitions for equation (11) because Beta-sub-X is not mentioned in equation (11). 2.3 Equation (13) is either (a) missing the summation sign “SigmaSub(Znot=Y)”, or (b) mistakenly includes “BetaSubZ/BetaSubT” instead of “1 - (BetaSubY/BetaSubT)” . The equation should accordingly be FCsubXY = ACEsubY x (SigmaSub(Znot=Y))(BetaSubZ/BetaSubT) x DFsubXYZ , or FCsubXY = ACEsubY x (1 - (BetaSubY/BetaSubT)) x DFsubXYZ , but not FCsubXY = ACEsubY x (BetaSubZ/BetaSubT) x DFsubXYZ . Proof: just plug equation (11) into equation (12). 2.4 I believe the following sentence written before equation (13) is wrong and should be deleted: “The sign must be changed because they represent the flow at the other BA.” Proof: the author correctly makes no such sign change in equation (13). 2.5 The author neglected to correct a typo pointed out. The first line of section 3 should read “moves”, not “move”. 2.6 The author neglects to acknowledge the undersigned for the insertion of equation (18) made crucial use of in Appendix 1 to derive equations (11) & (24). 2.7 The third sentence prior to equation (23) mistakenly refers to “Equation (22)” instead of “Equation (23)”. 2.8 I believe the following sentence written immediately before equation (23) is wrong and should be deleted: “It also indicates the direction of the flow and since the sign of the flow changes from the flow out of BA1 to the flow into the other BAs in question, the sign must be changed to be consistent with the sign of the ACE of BA1.” Proof: the author correctly makes no such sign change in equation (23). 3. For the benefit of commenters, and with the indulgence of the drafting team, I offer my “proof-of-concept” rewrite of the “Calculating ACE Distribution Factors” paper, in precise operational mathematical detail including numerous new Appendices providing detailed computation examples requested by the original paper’s author Howard Illian and by the drafting team that may have helped drive the drafting team’s “recent experiment” whose detailed account I am requesting in my comment #1 in this section. Download by pasting either of these urls in browser window: http://www.blohm.cnc.net/ACEDistributionFactorsRevised.doc http://www.robertblohm.com/ACEDistributionFactorsRevised.doc 4. NERC's IT department should investigate the feasibility of online comment formats that accommodate mathematical notation. 5. The NERC IT department should remove a bug from the software used for these online comments. My true phone number is not 609 585 5451 as listed herein. My true number is 609 442 6343, or even 206 279 7713 . Either of these numbers was rejected as not valid by NERC's online software. So I lied and entered my previous fixed-line phone number to get through that obstacle and proceed with these comments.
Group
E.ON U.S.
Brent Ingebrigtson
E.ON U.S.
No
See Response to Question 5
No
See response to Question 5.
No
See response to Question 5
No
See response to Question 5.
Before addressing specific ADF/BATL parameters (as in questions 1 thru 4), the basic ADF/BATL concept needs broad acceptance. This posting is the first time ADF/BATL has been presented to the industry. It seems premature to be setting specific parameters until the industry is comfortable with the overall proposal. It also seems that even if ADF/BATL is an appropriate technical solution, it raises issues related to its implementation within the functional model. ADF is a proxy calculation which correlates a BA’s ACE to flows on specific transmission lines or flowgates. Since the ACE calculation is non-locational, will the correlation to specific flows be sufficiently accurate and provide consistent results? Can restricting a BA to the BATL be trusted to resolve flow problems in the most expeditious/efficient manner? When flow problems arise, it may be more effective for a RC/TOP to work with (or direct) a BA on corrective actions than spend time and effort implementing a BATL response. Unless excessive ACE (within BAAL constraints) frequently causes line/flowgate loading problems, the use of ADF/BATL may not be necessary. How broad is the scope of the perceived excess ACE/line loading problem? The ADF/BATL proposal introduces several technical parameters that will need to be established, monitored and records retained. This will be an additional compliance burden on the RC, TOP and BA and compliance authorities. Clarity is needed for the following issues: • There is discussion of limiting it to the range of +/- L10 but the white paper also mentions that “The absolute value of a BATL should never be less than 1 MW and BATLs should be rounded up (in an absolute sense) to the next whole MW.” E.ON U.S. believes that, these two concepts seem to conflict. • There is mention that if “A BA that allocates its Frequency Response into multiple zones must provide a “pseudo-ACE” for each zone it uses”, but what if the BA has Pseudo BA’s modeled in the IDC. Would this require separate ACE (or imbalance) limitations? • What would constitute violating this? If there is a 15 minute window and you are within the limit for one AGC cycle does the clock reset? Is it based on clock minute average? What is the “after the fact” measure of performance? • Since the indicator for this is a measure of transmission congestion (although not specifying which flow gate), would the indices be available for regulated generation to see as constraint on ACE as the current BAAL limitations are presented to them? • A 0.5% threshold is too low. For a 200 MW limit on a flowgate, a BA with an ACE outside of +/- L10 would be subjected to BATL if it is contributing 1 MW to the flowgate. However, if you are outside of +/- L10 , the BA should be aiming to get back within its bounds regardless of this new BATL so a 1 MW contribution to that limit will not trigger a very different response from the BA.
Group
Northeast Power Coordinating Council
Guy Zito
Northeast Power Coordinating Council
No
See comments to Question 5.
No
See comments to Question 5.
No
See comments to Question 5.
No
See comments to Question 5.
There are two concerns with the fundamental concept as proposed: 1. ACE is the net balance of a BA’s generation/load/interchange, and is not directly linked to the flow direction on the ties. The flow on the ties due to ACE correction depends a great deal on the point of generation pick-up/reduction, and on the interconnected network impedance. Its correction is therefore directionally specific which makes it unable to be linked to the distribution factors and the flows on ties or any identified flowgates. On the other hand, transmission congestion is direction-specific. Forcing a relationship between ACE/its correction and distribution factor on specific transmission facilities is a technically flawed concept. ACE and frequency response are not necessarily always in the same direction (pair). Some of the equations in the paper incorrectly assume that they are always the same. 2. The proposal is very complex. A simpler approach would allow operators and others in the industry to more easily understand and support. We also believe proposing to use the IDC as an input to a real-time tool has potential problems; ownership of this tool, the availability provisions required by the tool, the explicit requirements to post all necessary data, backup provisions, etc. We continue to support the concept of bounding ACE operation at the BA level, in conjunction with the BAAL limits. Suggest using static ACE bounded values as opposed to a dynamic model as proposed in the posting.
Individual
Denver York
East Kentucky Power Cooperative
 
Yes
 
No
Allowing 5 minutes for the System Operator to recognize that there is a persistent problem that requires action is sufficient. However, some actions the SO could take would require longer than 10 minutes to effectuate. For example, if additional generation from an off-line combustion turbine is needed to reduce the ACE to within the BATL, it may take more than 10 minutes to bring on and get loaded.
 
 
Group
WECC RC
Linda Perez
WECC RC
Intentionally left blank
Intentionally left blank
No
A TOP that is responsible for a SOL limit violation is responsible to take actions without intentional delay to resolve the SOL. We suggest making the BATL time limit the same limit as the Frequency Trigger Limit 10 minutes, if violating the limit is causing undue burden on the interconnection it should be resolved immediately. A TOP can’t wait to take actions for a SOL violation while a BA waits 15 minutes to get below a BATL.
Intentionally left blank
There are currently standards that support corrective actions by Balancing Authorities when its excessive ACE contributes to or causes action to be taken to correct a System Operating Limit problem. Duplication of standards creates confusion. When operating under CPS2 there was little involvement needed by the RC due to the BA’s monthly average created a score by which the BA could monitor its performance. Almost all of the BA’s in WECC are also registered as a TOP, as a TOP they are responsible for the TOP Standards listed and as a BA have the ability to take action. TOP-001-1 R1, R4, TOP-004-2 R1, R4, R6, TOP-008-1 R1, R2. RBC, as implemented in WECC has increased the workload for the WECC RC’s, there are 25 BAs participating in RBC and 1 RC. The eastern interconnection has 12 BA’s and 8 RC’s monitoring RBC
Group
MRO's NERC Standards Review Subcommittee
Carol Gerou
Midwest Reliability Organization
Yes
 
Is staying with utilization of L10 as a “minimum ACE” in keeping with the intent to establish new, improved, methods of BA control?
Yes
 
Yes
 
A. Making adjustments to parameters “as more operating experience is achieved” would require a trial period. B. With respect to Reliability Coordinator involvement “minimizes market, code of conduct, computational accuracy, etc. issues”, in the case of non-MISO market members, it is difficult to discern if information/changes are initiated by the MISO Reliability Coordinator or by the MISO Market Operator. C. More clarity is needed on how “zones” are defined. D. The first four questions assume we agree with the need for the proposal in the first place. It is our understanding that the need for this proposal was the belief that under the RBC standard, a BA could somehow foresee future frequency and would choose to run continuously with a very large ACE counter to frequency and take no action. It is virtually impossible for a BA to have a large ACE and not impact frequency. It is generally irrational to operate counter to other Balancing Authorities (overgenerate during shortages or undergenerate during surpluses). I have heard of no cases of transmission issues due to the field trial. In addition, frequency control in the AGC window of time has improved in the past few years. The IROL standards provide transmission protection and we should not add unnecessary complexity.
Group
We Energies
Howard Rulf
We Energies
Yes
 
Yes
 
Yes
 
Yes
 
In today’s market environment, BA’s can encompass several member companies who contribute to an aggregate ACE. In such cases, would like to see those BAs utilize similar methodology for implementing flowgate relief among schedule parties. For example, compare actual flows to scheduled flows, and assign relief among parties on a pro-rata basis in accordance with deviation from actual.
Individual
Kasia Mihalchuk
Manitoba Hydro
Yes
We experience many TLR’s to eliminate SOL’s as a result of an adjacent system taking advantage AGC control perfromance limits. As a result, flowgate limits already contain a component of TRM that accounts for AGC deviations under the standards. A 0.5% allowable limit would place the AGC deviations on a comparable reliability threshold for the curtailment of other impacts on the interface.
No
This should be tested and monitored with field trials to ensure that a BA, having significant impact on a flow gate (i.e. a high ADF), has a small enough BATL to address the impacted flow-gate and achieve the desired congestion relief. An ACE limit of L10 may not be restrictive enough to achieve the desired loading relief on a flowgate path.
Yes
 
Yes
 
 
Group
Arizona Public Service Company
Mike Mraz
Information Services - Power Operations
Yes
 
Yes
 
Yes
 
No
The BATLs are effectively dynamic limits. Their update interval should be commensurate with the time limit allowed for exceeding the limit, 15 min. This will allow the actions of other BAs also affected by congestion on the same path, as well as actions already taken by the BA, to be reflected in the limit in a more timely fashion. APS recommends the update interval be 15 min.
1) APS expects that other measures to address path loading will be taken before the revised BATL’s will be received from the RC. For example, tags/schedules will likely be cut before the BATLs are updated and received. 2) The elimination of CPS2 and addition of this BATL (dynamic or static, regardless of its determination), will not prevent a BA from “leaning” on the interconnection. The only metric to discourage this in the proposed standard is CPS1. But the CPS1 performance metric is a 12-month measure and still allows a BA to spend a significant time benefitting from the interconnection. 3) In the process of determining the BATL, if there are no congested paths and effectively no BATL, rather than sending a zero to the BA an excessively large value (e.g. 999999) should be sent. The will allow the value received by the BA to always be used/implemented as a limit and will conform to the intent to make the minimum BATL = L10.
Group
Western Electricity Coordinating Council
Steve Rueckert
wecc
 
 
No
A TOP that is responsible for a SOL limit violation is responsible to take actions without intentional delay to resolve the SOL. We suggest making the BATL time limit the same limit as the Frequency Trigger Limit 10 minutes, if violating the limit is causing undue burden on the interconnection it should be resolved immediately. A TOP can’t wait to take actions for a SOL violation while a BA waits 15 minutes to get below a BATL
 
There are currently standards that support corrective actions by Balancing Authorities when its excessive ACE contributes to or causes action to be taken to correct a System Operating Limit problem. Duplication of standards creates confusion. When operating under CPS2 there was little involvement needed by the RC due to the BA’s monthly average created a score by which the BA could monitor its performance. Almost all of the BA’s in WECC are also registered as a TOP, as a TOP they are responsible for the TOP Standards listed and as a BA have the ability to take action. TOP-001-1 R1, R4, TOP-004-2 R1, R4, R6, TOP-008-1 R1, R2. RBC, as implemented in WECC has increased the workload for the WECC RC’s, there are 25 BAs participating in RBC and 1 RC. The eastern interconnection has 12 BA’s and 8 RC’s monitoring RBC
Group
FirstEnergy
Dave Folk
FirstEnergy Corp.
Yes
 
Yes
 
Yes
 
Yes
 
 
Group
Nucor Corporation
James Brew
Brickfield Burchette Ritts & Stone
 
While we fully agree with the concept of a minimum value for BATL, it is not obvious to us that L10 is the “correct” minimum value. Our understanding is that this minimum value will be re-evaluated as the field trial progresses and as additional, technically-based methodologies are developed.
We see no reason that the time limit cannot run in parallel with the IROL 30 minute requirements. It appears that there is sufficient synergy between the IRO and BAL standards that the required actions of the RC and BA would work in a synergistic manner to limit actual flows caused by nonzero ACE that aggravate congestion on a flowgate. Please note further comments below.
We believe that coordinating the updates of the BATL with the IDC and WebSAS is good use of existing tools and aids in keeping the RCs and BSs in the same information loop with technically parallel information used for congestion relief from other causes. This should aid in implementation and also provide a broader picture from which to base decisions.
Several times during the development of the Tv standard for BAAL it was stated that the 30 minute time limit for BAAL was chosen arbitrarily. In fact the concept that Tv would be set such that it would encompass 50% of the probability of the next generation contingency. However, this time period turned out “to be much greater than 30 minutes” and the “SDT chose 30 minutes to keep it the same as that used in the IROL standard in order to minimize the learning curve for operators as they implemented the BRD standards.” Again, while we agree that a time limit must be incorporated in the standard, we do not feel that there has been sufficient consideration for simply changing the ACE limit during periods of congestion, as opposed to introducing a new time limit that is based on an additional arbitrary value. There is sufficient harmony between the IRO and the proposed RBC standards that the 30 minute limit for the BAAL should apply to the BATL as well. In addition we are concerned that some confusion may be introduced by the timing of responses to congestion. Is it the SDTs intent that the BATL will prevent, or reduce, the likelihood of TLRs as Purpose Statement B appears to address? Or, is it the intent of the SDT that the BATL would be reactionary to a TLR event as set out in Purpose Statement D? To prevent potential conflicts it seems logical that the RC would want everything moving in the same direction at the same time (i.e., no delays in responsive actions). A 15 minute limit for BATL may unnecessarily induce a “wait and see” approach. We are very interested in the SDT reaction as well as the RC participating in the discussion.
Group
Midwest ISO Standards Collaborators
Jason Marshall
Midwest ISO
No
No technical justification of this number is provided in this whitepaper. A detailed analysis needs to be conducted and presented to industry to justify this or any other number. Given the extensive work being done by the IDCWG to add more granularity to the model down to the generator level in the gen-to-load project, we would like to have a better idea of how this work will not conflict with the work of the IDCWG or whether the work of the IDCWG will achieve the results desired under this process but just in a different way. It is unclear whether such bounds are needed for those Balancing Authorities who have seams agreements for addressing flows on coordinated flowgates where more-specific generator action is taken – perhaps this methodology should be supported in instances where agreements are not already in place to address impact on coordinated flowgates.
Yes
We agree with the concept that there should be a minimum bound established for each BA that recognizes general operation of a Balancing Authority. This seems like a reasonable starting point that should be evaluated further; however, with anticipation that the frequency bias may eventually be allowed to be changed to better reflect actual response, we do not believe the team should be linking its proposal to a calculation based upon the bias, as the resulting value may be unreasonably restrictive for large Balancing Authorities given the non-linear results of the CPS2 calculation..
No
We would note that the proposal is not technically-based, and our answer is dependent upon whether the limits developed properly consider the operating range needed of the balancing authority to manage all changes within its system that should be considered in the planning and operation of the system.
Yes
We agree with a methodology that is consistent with the timing used by other processes providing congestion relief.
The Relative Contribution of DF as Compared to ADF in section 2 of the whitepaper is technically flawed. It presumes that energy can be sourced without sinking somewhere. The paper also presumes that good estimates of actual system frequency response are static. They are not and change continuously. Further, they are typically only accurately known after an event happens. There are several problems with the Appendix. First, the paper identifies T as a component of ACE. It appears that ΔT (schedules minus actual tie line flows) is not represented appropriately. T is used in place of ΔT and since ΔF is explicitly identified, we can only assume it was intended to represent one component of ΔT. The development of equation 23 from equations 18-22 needs further explanation. The whitepaper suggests that equation 23 is derived from equation 22. It appears it is really derived from a combination of 6 and 18 through 22. The whitepaper in the same paragraph states that equation 22 is the ADF for BA1 and normalizes ACE for BA1 to 1 MW. This needs further explanation. We think that the intent is to simply say that equation 22 was normalized but it is not clear. Further, equation 23 is the first inclusion of DF. A few more intermediate equations would explain this concept better. While we agree that this approach shows promise with this simple example of one BA having a non-zero ACE, we are concerned it could quickly break down with multiple BAs with non-zero ACE and encourage the drafting team to work through examples with multiple BAs with non-zero values of ACE. The first four questions assume we agree with the need for the proposal in the first place. It is our understanding that the need for this proposal was the belief that under the RBC standard, a BA could somehow foresee future frequency and would choose to run continuously with a very large ACE counter to frequency and take no action. It is virtually impossible for a BA to have a large ACE and not impact frequency. It is generally irrational to operate counter to other Balancing Authorities (overgenerate during shortages or undergenerate during surpluses). We are aware of no cases of transmission issues due to the field trial. In addition, frequency control in the AGC window of time has improved in the past few years. The IROL standards provide transmission protection and we should not add unnecessary complexity. Though operation under the Field Trial of the Balancing Authority ACE Limit (“BAAL”) has not demonstrated a reliability need for this proposed approach for a transmission-based ACE limit, we are supportive of imposing a limit at times when excessive ACE (as the industry will define) is causing or contributing to a transmission loading issue. The caveat to that statement is that methodology must allow for a practical and achievable operating range for the Balancing Authority.
Group
Bonneville Power Administration
Denise Koehn
BPA, Transmission Reliability Program
No
There should be no maximum contribution to congestion. If a BA’s impact is greater than .5% then they should be assigned that contribution. Please explain reasoning behind .5% maximum threshold? If anything, a threshold should be established which indicates that if the impact is below this level, then the contribution can be ignored.
Yes
 
No
The answer would be yes if the associated implementation of BATL were at 90% or below. TOPs are responsible for keeping the IROL/SOL for going over the limit, not just mitigating once it goes over the limit.
Yes
In WECC we have path limits that continually change based on system conditions, are you proposing WEBSAS would be continually updating during a flowgate congestion risk?
TOPs are responsible for keeping the IROL/SOL for going over the limit, not just mitigating once it goes over the limit. So, the implementation of BALT should be at 90% or less. RBC shouldn’t cause any impact to TOPs. There should be no maximum contribution to congestion. If a BA’s impact is greater than .5%, then they should be assigned that contribution. Please explain reasoning behind .5% maximum threshold? Please explain how you would calculate a BA DF. The only way BPA knows of creating DF is a Bus source to a Bus sink. This may have a large impact on the feasibility of this methodology and our ability to support it. The statement on page 3, “, BALTS should be provided to BAs on a timing that coordinates with other transmission loading relief procedures presently used”. Our view is that this procedure should be imposed prior to other transmission loading relief procedures; RBC shouldn’t impact or interfere with the TOPs ability to manage their transmission levels below the limits. This method seems overly complicated and the impact due to frequency response should be minimal. Do you have any studies to show the impact due to frequency response has a significant impact? BPA thinks that simply using DF as a measure of impact to a path would be a simpler and more manageable process. The drafting team mentions using WEBSAS. Currently WEBSAS is used for a minor portion of the WECC paths and would need to expand significantly to be usable for this proposal.
Individual
Thad Ness
American Electric Power (AEP)
No
It is hard to determine what the reliability basis is for this threshold. It is unclear what operational impacts this would cause or division of BAs into zones to achieve proper implementation/desired effect.
No
If you are not going to limit the ACE inside the L sub 10 what effect does this have?
No
See the comments under number 5
No
See the comments under number 5
As AEP stated to draft 2 of the SAR, the industry already has sufficient Standards and Requirements that, if enforced correctly or applicability is expanded, would have the desired results. In order to help address balancing/regulation operational issues, there needs to be more focus on the reliability impacts from the lack of accountability by some of the GOPs. Today, all of the balancing responsibilities fall upon the BAs without providing clear obligations to the GOPs. AEP does not find the benefit that would be achieved, compared to the costs involved. Effort should be focused on continuing to develop and implement the BAAL approach that is currently under field trial rather than start-up another complex and difficult methodology to implement. Furthermore, this approach is likely not to aid frequency response and there are concerns that it might be detrimental to frequency response. Trying to address congestion through the balancing function is a contradictory concept. Also, this would drive away from the direction of RTO/ISO BA consolidation. AEP would suggest that if the SDT is seriously considering this approach, NERC should host a webinar to walk through real scenarios and solicit input from operational staff.
Individual
Doug Hils
Duke Energy
No
Without further analysis of the value, and absent a technical justification for using the threshold proposed, we feel that the industry would be more receptive to accepting a value consistent with what is currently utilized in the industry for curtailment of transactions using a similar methodology with distribution factors. If what is acceptable today under similar processes is different in the individual Interconnections, then this methodology may need to accommodate the threshold used on an Interconnection basis. Given the extensive work being done by the IDCWG to add more granularity to the model down to the generator level in the gen-to-load project, we would like to have a better idea of how this work will not conflict with the work of the IDCWG or whether the work of the IDCWG will achieve the results desired under this process but just in a different way. It is unclear whether such bounds are needed for those Balancing Authorities who have seams agreements for addressing flows on coordinated flowgates where more-specific generator action is taken – perhaps this methodology should be supported in instances where agreements are not already in place to address impact on coordinated flowgates.
Yes
We would note that the proposal is not technically-based however we agree with the concept that there should be a minimum bound established for each BA that recognizes general operation of a Balancing Authority. Though we cannot say that L10 is the proper methodology, we do recognize that MW bounds consistent with the current CPS2 L10 limits in place would be consistent with what has been accepted in historically but not under such a restrictive measure of ensuring that the bound is not exceeded for more than 15 consecutive clock-minutes. With speculation that the frequency bias may eventually be allowed to be changed to better reflect actual response, we do not believe the team should be linking its proposal to a calculation based upon the bias, which already may be unreasonably restrictive for large Balancing Authorities given the non-linear results of the CPS2 calculation.
No
Our answer is actually "yes and no". We would note that the proposal is not technically-based, and our answer is dependent upon whether the limits developed properly consider the operating range needed of the balancing authority to manage all changes within its system that should be considered in the planning and operation of the system.
Yes
We agree with a methodology that is consistent with the timing used by other processes providing congestion relief. While we believe the whitepaper contemplates the RC having some role in the determination, on a constraint by constraint basis, of these BA bounds, we need more detail on how this is proposed to work, especially the communication of the changing limits to the BA. It appears that this will have to be an automated process initiated by a system and communicated to the BAs. As there may be some cases where balancing is being performed by a market entity, this information will have to be communicated without revealing non-public transmission data.
Though operation under the Field Trial of the Balancing Authority ACE Limit (“BAAL”) has not demonstrated a reliability need for this proposed approach for a transmission-based ACE limit, we are supportive of imposing a limit at times when excessive ACE (as the industry will define) is causing or contributing to a transmission loading issue. The caveat to that statement is that methodology must allow for a practical and achievable operating range for the Balancing Authority.