Item 18: February 2021 Winter Storms After Action Report Follow-up re Load Shed and Circuit Sectionalizing — original pdf

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Item 18 February 2021 Winter Storms After-Action Report Follow-up Actions Pertaining to ERCOT-Mandated Load Shed Tom Pierpoint Vice President, Electric System Engineering & Technical Services February 14, 2022 ©2022 Austin Energy Topics • Austin Energy February 2021 Winter Storms After-Action Report • Impact of ERCOT-Mandated Load Shed • Circuit Reconfiguration and Sectionalizing • Key Actions to Add Circuits and Further Capacity to Manual Load Shed • After-Action Report Status of Follow-up Actions • Questions & Comments 2 ERCOT must mandate Load Shed at any time, frequency, duration or level to stabilize the Texas Electric Grid Austin Energy has a broad strategy to meet ERCOT- Mandated Load Shed 3 Impact of ERCOT-Mandated Load Shed 4 Electric Circuit Portfolio for ERCOT-Mandated Load Shed Category of Circuit Manual Load Shed Characteristics of Circuit Can be used for cycling Under Frequency Load Shed (UFLS) Required by ERCOT to be reserved and pre-programmed Can be used for cycling in specific situations Dedicated / Industrial Circuits and customers that cannot be cycled Customer-side curtailment instead of power interruption Downtown Underground Network Circuits likely damaged or destroyed by cycling Customer-side curtailment instead of power interruption Critical Load – Life Sustaining No life-sustaining facilities lost power 5 Circuit Reconfiguration & Sectionalizing Each situation must be carefully evaluated by skilled engineers and field technicians for feasibility. Streets & Buildings Other Utility Infrastructure Major Electric Lines Detailed Electric Topology Some factors to consider • Sectionalizing originally implemented for reliability, not load shed • Location of critical load customers • Pole loading, circuit density and 3rd party attachments • Affordability (dependent on the situation) Load Shed Sectionalizing Pilot • Analyzing 7 circuits for manual intervention • More circuits would require automation Primary challenges of large-scale Sectionalizing • Critical load customers must be at head end of circuit • Changes to Control Center computer • Build-out of two-way wireless communications system • New equipment and modify existing equipment on poles • At least a 3–5-year timeline 6 Key Actions to Add Circuits and Further Capacity to Manual Load Shed Category Manual Load Shed Under Frequency Load Shed Dedicated / Industrial Downtown Underground Network Critical Load – Life Sustaining Additional Flexibility to Reassign Circuits Industrial Curtailment Program Curtailment for Commercial Reconfigured 3 Critical Load Circuits 7 After-Action Report Status of Follow-up Actions 8 Questions and Comments Thank You! 9