GMD Voltage Collapse Study Terry Volkmann 2016 Fall Reliability Conference November 2, 2016 1
GMD Voltage Collapse Studies in Wisconsin and Maine Overview: Modeling shows GMD Voltage Collapse Issues: Power Grid modeling with GMD module Voltage Collapse Results: Wisconsin & Maine Status of FERC GMD Standard Approval FERC Approved NERC GMD Std (TPL 007 1) on Sept 22, 2016 FERC Directives for Improving the GMD Std Major Flaws in the present NERC GMD Standard Serious GIC Induced Harmonic Issue Ignored by the GMD Std Cap banks tripping out of service Ignored by GMD std Presidential Order to Protect Grid against Solar Weather Issued October 13, 2016 2
Typical Power Grid Modeling for GIC Calculations GIC Power Grid Modeling Providers: PowerWorld TM Siemens PSSE General Electric PSLF And Others 3
Setting Up GMD studies Modeling performed with PowerWorld TM Classify transformer types single vs three phase, shell vs core form, auto vs 2 winding, delta vs grounded wye Determine Transformer geographic location Build DC model of the grid Components & Transmission Line DC resistances Delta windings are open circuits Ground resistances Apply GMD E fields to calculate the GIC currents Apply a field of 1 Volt per km, results linearly scale to larger values Vary the field angle from 0 to 180 degrees 4
Solve the AC Model Calculate GIC currents for each E field angle (in 15 deg increments) Calculate Transformer Reactive losses (MVARs) with GIC currents Use transformer saturation K factor based on transformer type and voltage Reactive losses (MVARs) are linearly scalable with GMD E Field magnitude Reactive losses are applied as additional transformer losses 5
Wisconsin Voltage Performance by GMD Field Orientation: Base Case 1.02 1.00 0 Degrees Voltage at Lowest pu Voltage Bus 0.98 0.96 0.94 0.92 0.90 0.88 0.86 Voltage Collapse at 0.95 pu 30 Degrees 60 Degrees 90 Degrees 120 Degrees 150 Degrees 0.84 0.82 0.80 0.0 5.0 10.0 15.0 20.0 25.0 30.0 Field Strength (V/km) 6
1.00 Wisconsin Voltage Collapse at 60 degree E Field Angle Voltage at Lowest pu Voltage Bus 0.96 0.92 0.88 0.84 Base Case Base Case with Transfers Major Gen outage Outage Capacitor Outages 0.80 0.0 5.0 10.0 15.0 20.0 25.0 Field Strength (V/km) 7
Prevents Grid Collapse 8 Grid Stability and Harmonic Mitigation System
Maine Voltage Collapse Studies 9
Maine Voltage Collase at E Field Angle of 135 degrees: Summer Power Flow Condition Voltage Collapse at 14 V/km at Coopers Mill and Albion Rd 10
Maine Voltage Collapse vs Geo Electric Field (V/km) Power Transfer Sensitivity Power Reduced to 78.5% Power World Modeling of Maine Grid Zero Power Transfer ISO PowerLimit Voltage Collapse Point does not Change when Power Flow Reduced to 90% Power Reduced to 90% ISO Procedures (i.e. reduced flows to 90% of limit) will not mitigate power grid disturbances nor lessen harmonics 11
Maine Voltage Performance by Blocking Level Neutral Blocking Improves Grid Voltage Collapse 12
NERC GMD Std (TPL 007 1) is FERC Approved as of September 22, 2016 Seven(7) specific Requirements (R1 R7) outlined for: GMD grid studies, establishing critical criteria, and developing corrective action plans 13
FERC Directives for Improvements of NERC GMD Standard (TPL 007 1) Re validate the. validity of the spatial average model Re validate latitude adjustment methodology PC or TP must study both spatially average and nonspatially average (peak) geo electric fields NERC should address effects of harmonics and tertiary winding heating Re evaluate the thermal analysis threshold Greater collection of GIC and magnetometer data with dissemination to researchers and equipment manufacturers 14
Major Flaw in NERC Std : Harmonic Distortion data from Idaho National Labs Testing September 2012 IEEE THD Voltage Standard 1.5% Potential for Upset and/or Damage to Customer Equipment 15
Major Flaw in NERC Std: GMD Harmonic Analysis R. Walling EPRI paper, March 2014 Dong, et.al. IEEE paper, 2001 ( or 6.3 V/km) Available GMD Harmonic Analysis to date confirms concerning THD levels related to low level GIC currents 16
20 Major Flaw: GMD E Field used in NERC GMD Transmission Planning Standard (TPL 007) Volts per km for peak area 5 min 15 10 5 0 5 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 280 290 300 310 320 330 Volts per km 10 15 20 25 Field Transitions thru Zero can result in Cap Banks Tripping Out and Unavailable for five (5) minutes or more 17
Presidential Order October 13, 2016 Coordinating Efforts to Prepare the Nation for Space Weather Events Sec. 5...the Secretary of Energy,.. shall develop a plan to test and evaluate available devices that mitigate the effects of geomagnetic disturbances on the electrical power grid through the development of a pilot program that deploys such devices, in situ, in the electrical power grid.. https://www.whitehouse.gov/the pressoffice/2016/10/13/executive order coordinating effortsprepare nation space weather events Whitehouse Order Issued after Three Years of Study lead by the Office of Science & Technology Policy (OSTP)
Questions? 19