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Initial Draft: Notes from 1/17 Meeting – please send comments to [email protected] Questions for PG&E, SCE and SDG&E Regarding the Final Demo A (ICA) Reports January 11, 2017 On January 10, 2017 a sub-group of stakeholders met to develop a list of questions for the IOUs that would help stakeholders better understand the Demo A results and the possible steps forward. These questions are not intended to reflect the views or positions of any one of the participating organizations. The questions are roughly organized into categories for ease of review. A) Questions About the Assumptions and Calculations Used in the Methodologies 1) What alternatives to the operational flexibility limit (in both the streamlined and iterative approach) did the IOUs consider? Why were these alternatives rejected? Are there other alternatives that could be considered? i) Other methodologies considered, including SCE method outlined in GRC (“planned loading limit”)? Do any potential alternative methods lead to different results? (1) WG: recommend continuing studies in long-term refinement. IOUs looked at one approach that did not scale well. SCE will provide additional detail on how operational flexibility is addressed within the methodology used in its recent GRC. ii) Using operational flexibility criteria as a limiting factor provides an unnecessary constraint within interconnection/fast track process? (1) Sahm: recommend that users can ID when reverse flow is the limiting criteria within interconnection screen, and if that issue can be resolved, what the next limiting criteria is (resolve in long-term refinement, need to ID specific timeline) (2) Need to better understand operational flexibility (especially high operational cases) within Rule 21 fast track/tariff discussions (3) Understand how the issue is flagged within interconnection and what is the mitigation option 2) How do the IOUs propose to move beyond the use of a heuristic approach for operational flexibility? i) IOU proposal: alternatives discussed within long-term refinement (Q2 2017) (1) Within alternatives or modifications to methodology, need to also understand how this would change the use of backflow criteria? 1 Initial Draft: Notes from 1/17 Meeting – please send comments to [email protected] ii) Clarification: operational flexibility and reverse power flow constraints are not synonymous. There are other instances where reverse flow may cause issues (ex: some voltage regulators not equipped to operate in reverse flow). So, operational flexibility limit (as “reverse flow limit”) would need to retain in normal configuration situations. (1) WG question: could run operational flexibility limit only for reconfiguration and on certain devices? iii) WG question: impact on computing time? (1) Marginal savings if reduced, use does increase computational time for iterative method 3) The operational flexibility criterion is intended to flag backflow across SCADA controlled switching devices. See, e.g., SDG&E Demo A Report at 39. Do the IOUs know the location of all SCADA-controlled devices for this modeling? Or do the IOUs instead consider the criterion to be violated if there is backflow across any node, irrespective of whether there is a SCADA device present? i) Yes IOUs can ID location of SCADA controlled switches, reclosers, and voltage regulators. Limitation criteria only applied to SCADA devices, and only limiting when the switches are NOT capable of back flow. 4) Likewise, have the IOUs catalogued the SCADA devices that can distinguish backflow from load/generation and tolerate backflow, and do the IOUs take this capacity into the account in the operational flexibility criterion? If the IOUs do not have detail on the location and capacity of all SCADA devices, what level of effort would it take to acquire that detail? i) WG follow-up: clarifying justification to replace relays. IOU justification is that it adds a directional component to the relay, to better understand where the fault is. 5) Does any amount of backflow trigger a violation of the operational flexibility criterion, or is there a limited amount of backflow that does not pose safety/reliability concerns (i.e. what is the level of minimal risk that is tolerable)? i) WG follow-up: does the operational flexibility criteria impact reliability? (1) IOUs – limited impact to reliability 6) Can the utilities quantify how frequently abnormal feeder conditions occur that would result in the type of feeder switching that the heuristic approach seeks to address? i) IOUs (PG&E): ~5% at any given time? ii) Can issue be bifurcated into 1) recommendations for initial system-wide roll out and 2) longer-term refinements? 2 Initial Draft: Notes from 1/17 Meeting – please send comments to [email protected] iii) WG follow-up: does this have an impact on how frequently ICA results are updated and mapped? (CYME models updated weekly, versus models updated in annual planning process). iv) WG follow-up: in what situations and at what levels of penetration is operational flexibility limit triggered, when does it require a mitigation response? v) WG follow-up: should the mapping display include an “optional display” option that allows users to toggle limitation criteria on/off? 7) If there is a preexisting condition on a circuit that limits its hosting capacity, can the IOUs still proceed with the ICA analysis to determine the next limit for that location? For instance, it is our understanding that PG&E specifies a hosting capacity of zero when there is a low voltage limitation but the other IOUs do proceed with the analysis. Why does PG&E stop running the ICA when it reaches the first violation, even if it is preexisting, whereas SCE and SDG&E continue to run the analysis when there is a preexisting violation to identify what the next violation would be? i) PG&E continues analysis to find limits for other criteria, but published limit is 0. ii) When addition of DER aggregates pre-existing conditions, then should consider preexisting, but not all pre-existing conditions will limit ICA so should they should not automatically limit ICA. iii) Going forward, a few means to explore how to limit impact of pre-existing condition, including better understanding hierarchy of circuits, means of changing limits when you can expect certain conditions like low voltage (but how to do in most practical means?) iv) Can IOUs provide written explanation of current application (can be done jointly) so we can refer to in WG final report? 8) In performing iterative calculations, are the IOUs modeling the substation bus? Do the methodologies allow flow from one feeder to another? i) SDG&E Yes, yes ii) SCE: no-reverse flow, limit at breaker, in reverse flow allow iii) PG&E: no limitations even in reverse flow simulation, but limited at substation transformer iv) What situations are necessary to use common bus calculation depending on existing LTCs, others? Updated modeling also necessary in CYME/SYNERGI (1) Can IOUs clarify differences with regards to modeling common bus? Include in WG report to support WG recommendations 3 Initial Draft: Notes from 1/17 Meeting – please send comments to [email protected] 9) It is our understanding that SCE and PG&E’s methodologies have locked down the voltage settings. SDG&E, however, allows them to change, and that appears to be one reason why its iterative calculations are less efficient. Why does SDG&E do this, and not the others? Does SDG&E have results that could help in evaluating the impacts of not locking down voltage settings, both with respect to the accuracy of the results and the computational time it entails? i) SYNERGI allows to change (SDG&E to double check if locks as well), CYME automatically locks ii) SDG&E - allowing them to change simulates real time scenarios, more accurate results iii) PG&E – would like to work with CYME moving forward but with respect to Demo A timeline/practicality of getting results, locked for Demo iv) Likelihood that unlocking voltage settings will increase ICA, but increases computational time as well 10) What PV load profile are the IOUs using, is it seasonally adjusted, and how did they derive that profile? i) To be answered in writing 11) The utilities have been asked to provide a more detailed comparison of their respective methodologies and assumptions (preferably in table form). Do they intend to provide these comparisons, and if so, when? i) IOUs agree to provide assumptions table (including showing areas of common vision but development differences between IOUs) 12) What accounts for the differences in voltage between the IOUs’ results on the IEEE 123 Feeder? According to Justin Fuller from IEEE, the voltage numbers should be the same between CYME and Synergi. i) To be answered in writing 13) What would be the key differences between the IEEE test feeder and more representative California feeders? What are the IOUs’ plan for evaluating and comparing methodology by using additional feeders? i) To be answered in writing 14) How are the IOUs using AMI data in the ICA results? i) To be answered in writing 4 Initial Draft: Notes from 1/17 Meeting – please send comments to [email protected] 15) Does part of the ICA development plan involve performing more accurate load forecasting? i) AMI data used to determine localized shapes, SCADA data at substation scales load profile (load profile varies throughout the circuit) ii) WG report: load forecast influences ICA and determined in DRP Track 3 (not necessarily scope of work for ICA WG) 16) With respect to thermal limits, it is not clear from the reports whether the IOUs are referring to a conductor or a transformer. Is there a tolerance for variation? Are they using the specific capability of the unit or applying some blanket tolerance measure? Can they be more specific on the device that is limited? i) No tolerance 17) In addition to the criteria already considered in the ICA methodologies, are any other metrics or criteria considered in determining impact to operational flexibility in the normal interconnection review process OR in the ICA? i) See operational flexibility discussion notes B) Questions Regarding the Data and Maps 1) When can we expect that PG&E and SDG&E will release functional maps and make them available online? i) PG&E: sometime this week, happy to share data in advance (USB) ii) SDG&E: sometime this week 2) Is PG&E willing to offer downloadable KML files? If not, why not? Please be as specific as possible regarding the precise concerns PG&E has, and if possible, why those concerns are unique to PG&E. i) No, due to physical security, infrastructure concerns ii) PG&E to provide what specific concerns are in writing C) Computational Processes and Power 1) To what extent are the differences in computational time between the iterative and streamlined methods reported by SDG&E due to hardware differences (i.e. running the analyses on server-based versus laptop computers)? Specifically can you quantify how much of a difference is due to the different computer systems SDG&E used? See SDG&E Demo A at 43. 5 Initial Draft: Notes from 1/17 Meeting – please send comments to [email protected] i) Iterative method run on laptops, streamlined method run at server-level with multithread capabilities ii) Estimate – iterative could be run 3-4x faster (estimate) if switched to similar serverlevel iii) Going forward, likely CYME/SYNERGI likely to be better equipped to handle multiprocessing going forward, there is a multiple license issue iv) WG follow up: which improvements incur what magnitude of cost? When could WG potentially see cost and time estimates? Follow up needed with vendors (licensing costs, server/cloud computing costs, etc.)before WG recommendation is possible. v) Framing: Need to define under which conditions trigger re-run of ICA (which parts are updated and how frequently should they be updated?) 2) To what extent is SDG&E’s computational efficiency limited by the software (SYNERGI)? Please detail the possible solutions that have been explored to address these software processing challenges. What software/hardware solutions is SDG&E intending to use if it moves ahead with the iterative approach, and how does it propose to reduce computational time and expense? i) Can SYNERGI automate data input? (1) Both CYME and SYNERGI can provide automatic updates but overrides whole model; need to determine how to update section X without overriding section Y ii) The WG would like to better understand which components of SYNERGI and which methodological choices (locking voltage, computational efficiency choices, etc.) impact processing time 3) How does computational time translate into costs for the utility? Have the utilities done any cost assessment of running the iterative approach on the full distribution system as it is currently formulated, and of what it would cost to run an improved iterative approach (for instance, using cloud computing or other server-based approaches)? When PG&E states that there are increased IT costs to using their current cloud-based approach, can you quantify those costs? 4) What are the differential costs between running iterative, streamlined, and the proposed blended approaches (taking into account computational time, differential IT resource needs, etc.)? 5) Are there barriers to moving towards cloud computing (besides cost)? If so, what are they and are there potential solutions to them that have been explored? i) Data management/cyber security issue? 6 Initial Draft: Notes from 1/17 Meeting – please send comments to [email protected] ii) Time/process of transferring data, synchronization issue when data exists in two different places 6) Are there barriers to parallel computing? If so, what are they and are there potential solutions to them that have been explored? i) ICA analyses run in parallel processes (each hour is run in isolation) D) Use Case Questions for Iterative and Streamlined Methodologies 1) How do the IOUs propose to use the results of the iterative approach to process interconnection applications in the near term? i) Many new limits developed through ICA can replace current fast-track limits (SCE, PG&E, SDG&E) (1) Existing screens F, G, L, M, N, O, P ii) ICA should be updated based on interconnection applications, queue, existing generation (1) Updated monthly, potential longer-term goal of more frequent updates, and replacing fast-track screens with a type of verification process (2) Some questions regarding time lag, application to interconnection, more applicable to Rule 21 discussion iii) PG&E: ICA can help categorize whether a project can be fast tracked or go through supplemental review. Specific components of fast track screens can be directly answered/replaced with components of ICA. This also better informs projects going through detailed study through better categorization of project issues. iv) PG&E: potentially focusing iterative method done on demand, for example running in supplemental review? v) WG question: what is the marginal added cost of doing more frequent updates (ex: weekly) or more intensive updates? (1) Can we quantify usefulness/accuracy of information if interconnection request comes in near end of month? (2) How to integrate into interconnection tariff? (3) Which components are specific to an interconnection application versus solved through monthly ICA update? (4) Rethink hierarchy of screens (fast track, supplemental, detailed study?) 2) Do SDG&E and PG&E propose to reduce the hour profile and node volume for their iterative calculations to improve computational efficiency, as SCE did? See SCE Demo A Report at 76-78. Will this simplification be done for individual interconnection studies or only for the purpose of running the iterative ICA on the entire distribution system? i) SDG&E: (1) Some node reduction applied (2) Hour reduction: built-in SYNERGI application not optimal, would like to go back and reprogram, similar to SCE strategy ii) PG&E: 7 Initial Draft: Notes from 1/17 Meeting – please send comments to [email protected] iii) iv) v) vi) (1) Node reduction not included in Demo but makes sense moving forward, particularly with CYME Gateway (additional nodes) (2) Hourly reduction: reducing hours (to 576) but ensure does not limit understanding of situations WG question: balancing level of reduction techniques with cost, time, accuracy of results? Which are included in initial system-wide rollout? Hourly reduction: (1) Proposal to reduce from 576 to 24 hr profile, still applicable to interconnection fast track use case (currently interconnection uses minimum loads), requirement should develop in coordination/with modifications with Rule 21 process, and in consideration of increasing IOU confidence in interconnection WG question: from IOUs, what is the proposed optimal hourly profile to use within each use case? (1) One option: 48 hours (24 hours of minimum load, 24 hours of high/peak load) – looking at both addresses different criteria limit issues (ex: thermal limit under minimum load, voltage limit on peak load) (2) If long-term goal to optimize design of systems providing solutions, need 576 profile? (ex: solar + storage solution) (3) Consider solutions with respect to impact on range of technologies as well Follow-up: IOUs can summarize different proposals they may be able to support, with regards to hourly profiles (including benefits and trade offs) 3) How frequently does each IOU plan to update the iterative results for the entire distribution system? 4) Will these system-wide results be used for Rule 21 interconnection proceedings, for planning purposes, for both, or for neither? 5) Could the IOUs intend update the periodic iterative results with circuit-level interconnection results that arise from Rule 21 interconnection results as those latter results come in, and the make the updated ICA results publicly available? 6) Can the IOUs do a location-specific iterative analysis (i.e. circuit by circuit) instead of doing an entire update of the analysis for the whole system? 7) How do the IOUs propose to use the streamlined approach for planning? SCE, for instance, mentions that the streamlined method will provide information necessary for “various uses cases” where it would be overly burdensome to use the iterative method. SCE Demo A Report at 4. What specific “uses cases” do the IOUs envision using the streamlined approach for? Follow-up requests for IOUs: 8 Initial Draft: Notes from 1/17 Meeting – please send comments to [email protected] Computing cost and time estimates: outline of IOU discussion strategy with CYME/SYNERGI (priority for 1/20) Specific discussion on planning use case (ex: targeted grid modernization updates) (priority for 1/20) More detail on operational flexibility alternatives (including for SCE - more detail on "planned loading limit" described in GRC) Development of common methodology table PG&E specific: written explanation of policy on sharing KML file data Proposed options for hourly profiles (24, 48, 576, etc.) – benefits and tradeoffs Written explanation of current applications of preexisting conditions Written explanation of differences among IOUs with regarding to modeling common bus Written explanation of what other reasons a no-backflow screen might need to be used beyond operational flexibility (Ex: for some voltage control devices, how the screen would apply if it was used just for those cases) (priority for 1/20) 9