Distribution Automation: Fault Detection, Isolation, and Restoration Jeremy Blair, P.E. jblair@entergy.com 8/31/2012

The Evolution of Sectionalization Install Fuses to reduce Exposure to Trunk Radial Recloser reduces Trunk Line Mile Exposure and Customer Count risk. ~25% reduction in Breaker CI. Feeder Breaker R New Radial Breakers reduce Trunk Line Mile Exposure and Customer Count risk Feeder Breaker R Tie Recloser can reduce breaker CI by another 25%!

FDIR Basics FDIR = Fault Detection Isolation Restoration Automatically: Isolates faulted line sections Switches to restore power to unfaulted sections Makes decisions using Overcurrent/reclosing Loss of Voltage (any phase typical) Loading prior to outage (typically) Preset capacity limits (typically) What the other switches see (typically) Does not typically LOCATE fault.

Variations & Considerations for FDIR Systems Switching Equipment & Coordination (Motor Operated Switchgear, Reclosers, etc.)

Equipment Assessment for Cost Effective FDIR systems Environmental Regular Maintenance Mechanical Speed Interrupt Requirements Motor Operated Switches Corrosion, Ice loading -Motor Operator -Mechanism -Blades Seconds Load Break Enclosed / Padmounted Switchgear Enclosed Mechanism Electronic Sectionalizer -Batteries Cycles Electronic Recloser Fault Break

Variations & Considerations for FDIR Systems Switching Equipment & Coordination (Motor Operated Switchgear, Reclosers, etc.) Logic Architecture (Centralized, Distributed)

Logic Architecture for FDIR systems Distributed logic provides: SCADA independence Ability for targeted deployments of switching and telecom equipment Avoid single points of failure without redundancy Centralized logic provides: One time large investment with low cost scalability Possibility for FDIR as a SCADA/OMS add-on Possibility for centralized support/programming Ease of system visibility within logic (capacity, multiple sources, multiple contingencies) Hybrid systems Centralized logic on localized controllers like RTU’s or compact hardened computers. Can be distributed to whatever level necessary…regional SCADA host, substation, switch controller

Variations & Considerations for FDIR Systems Switching Equipment & Coordination (Motor Operated Switchgear, Reclosers, etc.) Logic Architecture (Centralized, Distributed) Communication Centralized, Peer-Peer, None IP, serial Public, Private Licensed Wireless, Unlicensed Wireless, Fiber, Copper

Variations & Considerations for FDIR Systems Switching Equipment & Coordination (Motor Operated Switchgear, Reclosers, etc.) Logic Architecture (Centralized, Distributed) Communication Centralized, Peer-Peer, None IP, serial Public, Private Licensed Wireless, Unlicensed Wireless, Fiber, Copper Deployment (Targeted, Risk-based, Systemwide) Utility Footprint Known Exposure zones Regulatory cooperation Operating rules (safety, capacity risk, switching procedures, etc.)

Value of Radial Sectionalization vs Value of Radial Sectionalization vs. FDIR assuming even customer & fault distribution Cust/2 Cust/2 Feeder Breaker R Miles/2 Miles/2 Sectionalization Risk Reduction= 1-{[(Cust/2)(Miles/2) + (Cust/2)(Miles)]/(Cust*Miles)} -for the cost of 1 Recloser per feeder: 25% CIAV 1-way Transfer Risk Reduction= 1-{[(Cust/2)(Miles/2) + (Cust/2)(Miles/2)]/(Cust*Miles)} -for the cost of 2 Reclosers per feeder: 50% CIAV R 2-way Transfer Risk Reduction= 1-{[(Cust/2)(Miles/2) + (Cust/2)(Miles/2)]/(Cust*Miles)} -for the cost of 1.5 Reclosers per feeder: 50% CIAV Cust/2 Cust/2 Feeder Breaker R Miles/2 Miles/2

Maximizing FDIR Effectiveness Targeted deployments based on historical feeder performance can be deployed anywhere Urban Rural High CIAV opportunity High CMAV opportunity Capacity Limits with full visibility allow for use of multiple sources Capacity limits allow for load or voltage constrained installations Scalability Distance & vegetation may require point to point, low throughput comm’s Can use meshing or short range comm’s

Maximizing FDIR Value Optimal Configuration 3 breaker, 2-way default = 50% CI reduction on two feeders Case by case: Goal is lowest $/CIAV and highest Customer Inclusion More than two sources not beneficial (high $/CIAV) unless needed for capacity/visibility Value of automation on second feeder Customer & Exposure Distribution Use of existing equipment provides low $/CIAV opportunities Use of capacity limits allow beneficial installation of FDIR systems in more scenarios.

Capacity considerations for FDIR systems 90% of hours at or below 70% of peak -Equipment/System Intelligence: -Entergy’s 70-90 rule -Visibility to support Capacity Limitations -Prevent or limit scope of transfer

FDIR Program Value: Real Entergy Numbers 117 Automated Load Transfer (ALT) systems in service at 2011YE 265 individual switches installed $13.25M in installed equipment 108,000 CI & 13,000,000 CM saved in 2011 ~$123/CIAV annually for one year program value ~$31/CIAV annually for four years program value Little maintenance required using magnetically actuated vacuum bottle switches & reclosers, so value grows with time!

Questions? Jeremy Blair, PE Entergy Jackson, Mississippi jblair@entergy.com