An Overview of Emerging Power Industry Standards for Geomagnetic Storms Adequacy Concerns

Proposed Standards from NERC/Industry Concerns about Science & Engineering Adequacy Design Standards - Protect Society from Consequences Grids - Unchecked Increase in Vulnerability of US Grid over many Decades Standard must Accurately Define Extremes of Storm Intensity & Footprint Standard must provide Assurance of Grid Security/Resilience NERC / Industry Draft Standard Claims to be 100 Year & Conservative Storm Analysis Consultants

Proposed Standards from NERC/Industry Concerns about Science & Engineering Adequacy Storm Analysis Consultants NERC Peak Geo-Electric Field Formula Factor Based on NERC Storm Intensity Profile Factor Based on Regional Ground Conductivity Estimates Threat Levels are Too Low Ground Models are Un-Validated & Can Be Readily Checked against Existing GIC Data Errors of Each Factor Being Too-Low Become Compounded, Greatly Increasing Overall Error Concern that Models do not Estimate this Constant Correctly

US/Canada Border Gulf of Mexico Proposed Standards from NERC/Industry Concerns about Science & Engineering Adequacy Storm Analysis Consultants

NERC Proposes Storm Strength of 100 Year Storm of 1170 nT/min Much Higher have been Observed since 1972 As high as 2688 nT/min – 230% Higher than NERC Proposes 1-in-100 Year Events ~5000 nT/min (~500% Higher) Defining a 100 Year Storm – Peak Intensity Storm Analysis Consultants Proposed Standards from NERC/Industry Concerns about Science & Engineering Adequacy

NERC Proposes Storm Strength of 100 Year Storm of 195 nT/min Observed 460 nT/min in March 1989 Storm - 235% Larger Large Storms Expand to Low Latitudes Defining a 100 Year Storm – Low Latitude Intensity Proposed Standards from NERC/Industry Concerns about Science & Engineering Adequacy Storm Analysis Consultants

Proposed Standards from NERC/Industry Concerns about Science & Engineering Adequacy Storm Analysis Consultants Many Observations that Exceed NERC Profile over last 30 Years Examine these Events to Show Potential for Even Larger dB/dt

The large Delta Bx has potential for ~ 3000–5000 nT/min disturbance The large Delta Bx observed on March 13, 1989 ~4500 nT Collapse over 3 Minute Interval in 1982 Storm Proposed Standards from NERC/Industry Concerns about Science & Engineering Adequacy These large Delta B Excursions indicate potential for dB/dt levels much greater than 2000 nT/min Storm Analysis Consultants

Proposed Standards from NERC/Industry Concerns about Science & Engineering Adequacy Storm Analysis Consultants

10 A Review of NERC Ground Models, Transformer Models & Independent Validations GIC Monitoring Can Tell Us A Lot About Storms and Responses of the Power Network and Apparatus that may be Harmed GIC Measures Meso-Scale Coupling of Storm to Critical Infrastructure Have Precise Information on Power Grid Asset Locations & Resistances Not Good Enough - Information on Ground Model Responses Not Good Enough - Validation of Apparatus Responses (Transformers) GIC Monitoring can Fill Important Knowledge Gaps Proposed Standards from NERC/Industry Concerns about Science & Engineering Adequacy

Proposed Standards from NERC/Industry Concerns about Science & Engineering Adequacy USGS Physiographic Provinces – NERC Ground Models (Un-Validated) Discuss Validation Concerns in these 4 regions Storm Analysis Consultants

Slide Presented by Jennifer Gannon USGS on Ground Conductivity Model Uncertainty on Nov 14, 2013 Storm Analysis Consultants

Slide Presented by Jennifer Gannon USGS on Geo-Electric Field Error Range due to Ground Model Uncertainty Storm Analysis Consultants

NERC Draft Standard Benchmark Geo-electric field scaling factors Actual Range 1.9 To 0.47 Similar Levels of Uncertainty Apply in Other Cases Storm Analysis Consultants

66 Amps at 4:39UT 74 Amps at 4:39UT Proposed Standards from NERC/Industry Concerns about Science & Engineering Adequacy Storm Analysis Consultants

Chester Transformer GIC Red & Green Indicate Polarity of GIC – Red Into Transformer, Green Out of Transformer Geo-Electric Field Orientation and Size of Vector Indicate Relative Direction and Intensity of Field 4:16 UT Simulated Storm and GIC Flows in New England Power Grid State Estimation at 4:16 UT May 4, 1998 Storm Analysis Consultants

17 Simulated Storm and GIC Flows in New England Power Grid State Estimation at 4:39 UT May 4, 1998 Storm Analysis Consultants

18 Simulated Storm and GIC Flows in New England GIC flow at Chester transformer neutral for 1 V/km geo-electric field at various orientation angles The 74 A & 66 A GIC Peaks indicate that Geo-Electric Field Intensity is more than 1 V/km Storm Analysis Consultants

Understates Peak GIC by Factor of 1.7 Simulated Storm and GIC Flows in New England Validation of Geo-Electric Field Models Storm Analysis Consultants

Understates Peak GIC by Factor of >2 A number of Published Papers show that NERC/Pulkinen Geo- Electric Field Model Significantly Understates Peak GIC for Similar Storm Intensity & Ground Conditions Proposed Standards from NERC/Industry Concerns about Science & Engineering Adequacy Storm Analysis Consultants

AEP July 15, 2000 Storm GIC Observations – NERC Meeting Presentation Neutral GIC Peak of ~37 Amps at Jackson Ferry 765kV Transformer Storm Analysis Consultants

AEP July 15, 2000 Storm GIC Observations – NERC Meeting Presentation Jackson Ferry 765kV Transformer in PT1 Region Storm Analysis Consultants

Peak ~37 Amps Peak 25 Amps NERC Model Under Estimates GIC by 50% NERC Model Has 32 Amps Peak Neutral GIC This Less GIC than Measured July 2000

Salem & Hope Creek Nuclear Plant Salem Nuclear Plant GSU Transformer Failure – Marc h 13, 1989 Storm Analysis Consultants

Peak ~90 Amps Peak 30 Amps NERC Model Under Estimates GIC by Factor of ~3 times NERC Model Has 48 Amps Peak Neutral GIC This ~50% of GIC Experienced March 1989 Salem Nuclear Plant GSU Transformer Failure – Marc h 13, 1989

Proposed Standards from NERC/Industry Concerns about Science & Engineering Adequacy NERC Standards Team – Need Only Co-Located Geomagnetic Field Measurements to Perform Validations That was Case in Maine GIC Measurement on TVA Transformer in Kentucky Storm Analysis Consultants

Magnetometers across US only Vary by Small % for this GIC Pulse Proposed Standards from NERC/Industry Concerns about Science & Engineering Adequacy Storm Analysis Consultants

Proposed Standards from NERC/Industry Concerns about Science & Engineering Adequacy Already Existing GIC Measurements can be Used to Validate Ground Models for most important parts of US Grid Storm Analysis Consultants

Geomagnetic Storms & Transformer Failures – Historic Trends IEEE Survey of GSU Transformer Failures Storm Analysis Consultants

IEEE Survey of GSU Transformer Failures Data Reported was Voluntary and ~½ of Utilities Participated All of These are Major Failures, Requiring Replacement 27% of All Reported Failures Resulted in Major Fire Event involved major catastrophic or collateral damage due to fires, tank rupture and/or oil expulsion. Storm Analysis Consultants

Reported to NRC but Not in IEEE Survey These are LER’s causing Reactor Scram Event (Transformer Problems not causing Scrams are not Reported) Storm Analysis Consultants

Network AutoTransformers are also Vulnerable and are not included in Summary A Storm with dB/d times larger could readily exceed ~300 Failed GSU Transformers alone

GIC – Transformer Losses & Heating Storm Analysis Consultants

34 GIC – Transformer Losses & Heating Increase in Tertiary Winding Losses Explains Transformer Increased Losses (0.7 MW) Storm Analysis Consultants

35 GIC – Transformer Losses & Heating Autotransformer Tertiary Winding Current Storm Analysis Consultants

Temperature Levels used by NERC failed to include Tertiary Winding Overheating Storm Analysis Consultants

NERC Temp Limits Plot of NERC Table 1 Upper Bound of Peak Metallic Hot Spot Temps Storm Analysis Consultants

180 C Short-time Conductor Limit GIC 180 C NERC Temp Limits Plot of NERC Table 1 & Ignored Tertiary Winding Conductor Temperatures 140 C Insulation Temp Limit Storm Analysis Consultants