Vic Howell – Mgr. Operations Engineering Support SOL Methodology Update Vic Howell – Mgr. Operations Engineering Support

Agenda Items The post-April 1st world and the RC’s role Credible Multiple Contingencies – Panel Discussion Seasonal Planning BES vs non-BES Facilities in the West-wide System Model (WSM)

Peak Operational Observations Absence of Path SOLs – fewer mitigations, more focus on RTA results TOPs are generally addressing SOL Exceedances as expected – new standards resulting in significant improvements on how TOP are monitoring their systems through RTAs Increased emphasis on developing Operating Plans in the Outage Coordination and OPA timeframes TOPs are questioning the use of proxy limits and are rethinking that philosophy. Some of those interfaces (Path limits) were being monitored because they were the contractual paths between TOPs. TOPs generally operating within TTCs, but occasionally exceed by 15-20% without seeing issues in RTCA Some confusion for what TOPs are to do in terms of coordination with their neighbors

Some Issues to Revisit Known interactions and TOP-to-TOP Coordination SOLs, IROLs, and Operating Plans Multiple Contingencies

Known Interactions Examples Nomogram for two Paths (for non-stability issues) Exports from TOP A to TOP B cause thermal or voltage issues in TOP B (or TOP C) During a planned transmission outage, Plant X generation causes thermal issues in TOP Y Proxy (Path) SOLs used to address many of these SOLs and IROLs do not address these issues – Operating Plans do Lots of flexibility in Operating Plans Can contain trigger points for operator action Can incorporate RTA results Can address “fairness” issues

What does the SOL Methodology say? “Nomograms may be used to provide operators with helpful guidance as part of an Operating Plan; however, they are not considered to be SOLs unless the nomogram represents a region of stability (i.e., the nomogram defines a stability limit).” “Similarly, TTC is not an SOL, and thus it is not an operating parameter. However, if a TOP so chooses, the TOP may utilize TTC (and Transfer Capability concepts) as part of an Operating Plan as a means by which to achieve acceptable pre- or post-Contingency performance and thus to prevent SOL exceedances.”

What does the SOL Methodology say? “Note that exceeding a TTC value in real-time operations does not constitute SOL exceedance.” “While TTCs and nomograms may serve as valuable mechanisms to prevent and/or mitigate SOL exceedances as part of an Operating Plan, these mechanisms are not a substitute for performing RTAs and does not absolve the TOP or the RC of its obligation to perform RTAs to identify SOL exceedance per the TOP and IRO Reliability Standards.”

What does the SOL Methodology say? “If, for example, heavy Path or interface flow is determined to be the cause of an SOL exceedance, it is expected that steps be taken by the associated TOPs and BAs per the pertinent Operating Plan to alleviate the condition by reducing flow on the Path or interface. The Operating Plans are expected to refer to the TOPs, BAs, and the RC applicable to the Operating Plan.”

How Can We Improve? Peak-led Path conference calls in 2018 Path Operating Guide modification What is the right level of Peak’s involvement in TOP-to-TOP coordination? It gets tricky when operational issues are about “fairness”

Multiple Contingencies (MC) TOPs determine MC credibility It is the responsibility of the TOP in whose TOP Area the MC Facilities reside to determine MC credibility Two categories of credible MCs: Always Credible MCs Conditionally Credible MCs

Always Credible MCs There are MCs that, based on historical performance and TOP risk assessments, have a sufficiently high degree of likelihood of occurrence such that the TOP determines that the MC should be protected against in all phases of the operations planning process and in Real-time operations. The credibility of these MCs does not change based on observable operating conditions, but rather their credibility is static based on TOP performance and risk assessments.

Conditionally Credible MCs MCs whose credibility is a function of observable system conditions The Conditionally Credible MC is credible only when the observable system conditions are present Example: those that become credible upon known and observable threats like fires, or adverse weather risks such as flooding, icing, tornados Example: when a breaker has a low-gas alarm, system operators might operate the system to account for the possible failure of this breaker during those conditions

What is Acceptable System Performance? Credible Multiple Contingencies (MC) Acceptable system performance for single Contingencies is more stringent than that of credible MCs Acceptable system performance for the post-Contingency state for credible MCs: The MC shall not result in: a. System-wide instability b. Cascading c. Uncontrolled separation

Multiple Contingency Issues Wide ranging TOP risks and TOP risk tolerances across the West Wide variances in the number of Always Credible MCs (ACMC) across TOPs – from zero to 200+ Significant inconsistencies in Always Credible MCs across RC Area Impacts the existence (non-existence) of stability limits and IROLs Many ACMCs increase risk of drastic operator action

Introduction of Panelists Terri Kuehneman – SRP Jerry Jackson – BPA Dede Subakti – CAISO Saad Malik – Peak

Discussion Topics What works well with the current approach? Do you like the flexibility afforded by the Always Credible MC vs. the Conditionally Credible MCs? Please explain. What problems or challenges, if any, does the current approach create for your TOP? What doesn’t work well with the current approach? Should we collaboratively develop a set of homogeneously applied criteria for identifying baseline Always Credible MCs? If so, what kinds of things could that criteria consider? If so, should we always allow TOPs do define additional ACMCs?

Seasonal Planning Seasonal Planning Process Revision Project To revise the seasonal planning process for the Peak RC Area to better align with the following industry changes: The new TOP and IRO standards The new IRO-017-1 Outage Coordination Process Peak’s revised SOL Methodology v8.1 The retirement of TOP-007-WECC-1a Changes in TPL standards

Seasonal Planning Facts May 2015 FERC Settlement Order states that “Peak shall coordinate the seasonal planning process for its RC Area.” Seasonal studies are not an extension of TPL studies No longer a need to determine historical Path SOLs NERC Reliability Standards no longer contain requirements to perform seasonal studies The standards require TPL Planning Assessments, outage coordination assessments, Operational Planning Analyses (OPA), and Real-time Assessments (RTA)

Study Window Overview IRO-017 Outage Coordination Process Seasonal Planning Process TPL-001 Planning Assessments OPA/RTA Operations Horizon Planning Horizon

Study Window Overview Seasonal Planning Process TPL-001 Planning Assessments IRO-017 Outage Coordination Process Planning Horizon Short-Range Process Long-Range Process

Project Objectives Design and implement a seasonal planning process that: Addresses TOP and RC needs Adds real value to operations preparedness Facilitates coordinated operations Dovetails with NERC required studies (TPL, IRO-017 Outage Coordination) Aligns with and supports the SOL Methodology v8.1 Retains the aspects of the current process that are working well and are adding value

Seasonal Planning Timeline – to finalize the revised seasonal planning process before summer 2018 studies Small team meetings

Preliminary Consensus Items Keep the four subregional study groups Focus on: Identifying and addressing issues that impact more than one TOP Identifying risks for instability, Cascading, and uncontrolled separation, and developing associated initial limits and Operating Plans Lots of flexibility in what is studied in any given season Make the long-range outage coordination process mandatory and modify as necessary Will not require TOPs to conduct their own independent seasonal studies Should add real, tangible value – not “turning the crank” Summer and winter, spring as needed Basecase development very important

BES vs. Non-BES Non-BES Facilities are outside the jurisdiction of the Reliability Standards (e.g., TOP, IRO, BAL) Peak doesn’t monitor non-BES Facilities for SOL exceedances – we monitor for impact on the BES The WSM contains both BES and non-BES Non-BES Facilities may need to be modeled to accurately determine BES SOL Exceedance Peak has no way of knowing definitively if a given Facility in the WSM is BES or non-BES

BES vs. Non-BES Central repository for WSM BES/non-BES status Additional data fields in COS addressed as part of data dictionary standardization effort BES or non-BES Impact to the BES Provides clarity and consistency for WSM monitoring