GIC Neutral Blocking System Prototype to Production

Transcription

1 IEEE Meeting in Augusta, Maine GIC Neutral Blocking System Prototype to Production July 22, 2015 SolidGround TM Installed in Wisconsin Dr. Arnold Vitols, ABB Sr. Scientist and Dr. Fred Faxvog, Sr. Research Scientist

2 Northern Lights

3 Total US Energy Usage (Billions of Kilo Watt Hours) Rate of Change of Magnetic Field (nt/min) US Electrical Power Usage & GMD Events 5,000 4,500 4,000 3,500 3,000 2, ,800 nt/min Carrington Storm [1] ,800 nt/min NY Railroad Storm [1] 6,000 5,000 4,000 3,000 2,000 1,500 1, [1] From J. Kappenman, Great Geomagnetic Storms., Adv. In Space Research 38, (2006), p Quebec ~ 500 nt/min ~ 2 V/km 2015 Storm 0 < 0.8 V/km Years 2,000 1,000 ~ 200 nt/min We have not witnessed a solar super storm since the US Power grid was created

4 35 W Bridge was Designed and Built in with the required Factors of Safety applied High Impact- Low Frequency Events Happen! Minneapolis, MN I-35 W Bridge Collapse Wednesday, 8/1/2007 6:05 PM /Rush Hour 13 Deaths 76 Adults Injured 22 Children

5 Major Solar Eruption in July 2012 WSA-ENLIL Model: Solar Wind Speed Earth CME Sun Extreme Solar Events Occur Statistically on average every 7.5 Years

6 Region Conductivity Map of Canada and US

7 Maintenance switch Solid Grounding Mode (Breakers) GIC Protection Mode (Capacitor Banks) Ground Fault Protection Mode (Spark Gaps) Transformer Neutral Kirk Key Interlock AC Breaker Power Resistor Triple DuraGap Spark Gaps DC Breaker Transformer Capacitor Banks To GIC Measurement Shunt Resistor Top Level Requirements GMD Field 30 V/km EMP E3 40 V/km and Reduced Harmonics Transformer Neutral Conductivity Monitor Grid Stability and Harmonic Mitigation System

8 SolidGround Operation has been Validated Software Simulation Modeling at the Univ. of Manitoba Before After High Voltage Ground Fault Current Testing in Phil. PA Passed 20 k Amp Fault Testing 20kA symmetrical 49kA peak Idaho National Laboratory Grid Experiment System Worked as Expected Blocked Injected DC Current when Detected by Electronics Grid Stability and Harmonic Mitigation System

9 Emprimus TM Ground Fault Spark Gap Description: Reliable Ground Fault Spark Gap Dual redundant gaps Three electrode pairs Unique gap preserving design Rugged supporting structure Designed for outside installations Passive device no electronics required Independently tested at KEMA Labs Performance Specifications: Breakdown Voltage: Adjustable from 8 to 20 kv DuraGap TM AC Current capacity: > 22 ka rms with 1.8 asymmetric offset Energy Dissipation per Arc: 3 M Joules Fault Duration 8 cycles Number of Operations > 30 Independently Tested, Redundant Ground Fault Spark Gap

10 Grid Stability and Harmonic Mitigation System What does the recorded data from operating system in Wisconsin tell us? System operated flawlessly on June 22 nd and 23 rd (K8 solar storm) Triggered into protection mode 14 times over two days Trigger level set for GIC of 5 amps System remains in protective mode for 10 minutes when triggered on Lack of any precursor disturbance before first impact NOAA and MISO alerts were not soon enough (15 and 4 minutes) to allow for effective mitigating procedures

11 22-Jun minutes 1:15 PM (CDT) 1:30 PM (CDT) Impending possible K7 Solar Storm 4 minutes 1:34PM (CDT) Protection provided with Solar Storm proceeding. NOAA notifies MISO of impending K7 Solar Storm MISO notifies Electric utilities of K7 Solar Storm Warning SolidGround operates 5 seconds after solar storm event providing protection 17-Mar-15 Normal Conditions 7:00 AM (EST) 7:49 AM (EST) Solar Storm Conditions with no warnings issued to the electric utilities Solar Storm Condition known to NOAA, No Warnings issued NOAA issues Warning

12 Grid Stability and Harmonic Mitigation System No Unintended Consequences found in two independent studies EPRI Report # , March 2014 Univ. of Manitoba report, Aug 2011

13 Unintended Consequences of a Procedures approach to mitigate GMD Impacts to Power Grids Procedures do not reduce VAR consumption Procedures do not prevent grid voltage collapse Procedures do not reduce damaging harmonics Procedures will most likely not be in place when the first of a series of GMD impacts hit the earth Warnings and alerts are usually sent 4 to 20 minutes before impact The first impact is many times the largest of the series Grid Stability and Harmonic Mitigation System

14 Maine Voltage Collapse vs Geo-Electric Field (V/km) Power Transfer Sensitivity Power Reduced to 78.5% Zero Power Transfer ISO PowerLimit Power Reduced to 90% ISO Procedures (reduced flows to 90% of limit) will not affectively mitigate GMD or reduce GIC generated harmonics

15 Grid Stability and Harmonic Mitigation System Not a 100 Year Solar Storm Problem: Recent Statistical Correlation between GMD events and Insurance Claims for Equipment Damage $2B+ Annual insurance damage claims Data from , No large storms Harmonic / Power Quality Issue Insurance Study By Lockheed/Zurich/NOAA: C. J. Schrijver, R. Dobbins, W. Murtagh, and S.M. Petrinec Space Weather Journal, 2014

16 Harmonic Distortion Data Idaho National Labs Testing / September 2012 IEEE THD Voltage Standard 1.5% Potential for Upset and/or Damage to Customer Equipment Keeping the Power Grid via Procedures and/or SVCs will not reduce harmonics or resulting equipment damage

17 GMD Harmonic (THD) Analysis R. Walling EPRI paper, March 2014 Assumes 500 kv single phase GSU and EHV transformers (400 to 1,000 MVA) Calculates GMD Voltage Harmonics for hypothetical network - results indicate IEEE 519 standard for Voltage THD is exceeded at low GIC current levels (less than 8 Amps) Dong, et.al. IEEE paper, 2001 Calculates GMD Current Harmonics for four transformer types Results for single phase transformer are in agreement with Current Harmonics from R.Walling EPRI paper ( or 6.3 V/km) Available GMD Harmonic Analysis to date confirms concerning THD levels related to low level GIC currents

18 Generation Impacts Generator Thermal Stress during a GMD Conclusions by Rezaei-Zare & L. Marti this study indicates that the relevant IEEE standards C50.12 and C50.13 require modifications to take into account the even harmonics of the generator current during a GMD event.. The standards underestimate the effective negative sequence current which contributes to the rotor heating. PESGM Authors: Rezaei-Zare and Luis Marti, IEEE PES, July 2013, Vancouver, Canada The simulation results reveal that the generator capability limit can be exceeded at moderate GIC levels, e.g. 50A/phase, and the rotor damage is likely during a severe GMD event.

19 Emprimus /Power World Modeled Geomagnetic Currents (Amps) at Maine Substations for a 100 year storm (Electric Field of 20 V/km) Transformer Description Neutral GIC (Amps) for Summer Peak Normal Transfers Neutral GIC (Amps) for Summer Peak Peak Transfers Larrabee Rd 345/115/13.8 # Mason Steam 345/115 # Yarmouth 345/22 # Chester 345/18 # Albion Rd. 345/115/13.8 # Surowiec 345/115/13.8 # Coopers Mills Road 345/115/13.8 # S. Gorham 345/115 # Keene Rd. 345/115 # Orrington 345/115/13.8 # Eight Substations with Neutral GIC Currents over 200 Amps for a One Hundred Year storm (20 V/km)

20 CMP (PSSE) Modeling of Geomagnetic Currents at Maine Substations Eight Substations with Neutral GIC Currents over 200 Amps for a One Hundred Year storm (20 V/km)

21 Chester Maine GIC Storm Data Linear Projection to 100 Year Storm (5,000 nt/min) gives neutral current of: Minimum = 500 Amps Mean = 1,000 Amps Max = 2,000 Amps 250 nt/min Data taken from EIS submission to Maine PUC, Oct 4, 2013 ~ 100 Amperes These large GIC currents are consistent with Power World modeling of the Maine and Wisconsin power grids and a recent EPRI paper by R. Walling

22 Reduction of Network Total GIC Neutral Blocking on 10% to 20% of HV & EHV Transformers: Significantly reduces total GIC in the network Minimizes the Whack-a-Mole effects % of Transformers with Blocking % Reduction of Network Total GIC 7 % 13.7 % 14 % 27.3 % 21 % 41.0 % Results derived from PowerWorld TM modeling of Wisc. & Maine Grid Stability and Harmonic Mitigation System

23 Decrease in Reactive Power (VAR) Demand with Installation of Transformer Neutral Blocking Systems Power World Modeling of ATC Wisconsin Power Grid Power Flow modeling with GIC currents present Calculated Reactive Power Demand (VARs) as neutral blockers are added to the network % of Transformers with Blocking % Decrease in Reactive Demand 7 % 14.6 % 14 % 29.2% 21 % 43.7% Significant Decrease in VAR Demand by Transformer Neutral Blocking Systems Results derived from PowerWorld TM modeling of Wisc. & Maine Grid Stability and Harmonic Mitigation System

24 Prevents Grid Collapse Grid Stability and Harmonic Mitigation System

25 Utility /Customer $ Savings VAR Consumption Reduced Cheaper than: Series Capacitors SVCs Uneconomic dispatch Reduced Stress / Damage to Generators and Transformers Maintains integrity of relay/controls No change in relay controls required Grid Stability and Harmonic Mitigation System

26 System Includes: Protective Spark Gap Dual Redundancy Neutral Current Monitoring - Rogowski Coil Neutral Voltage Monitoring Voltage Probe

27 System Cost $250K + 150K Installation, $400K Total If 1,000 were installed in US cost = $400M or one time cost/person of $1.25 Easily offset by avoidance of uneconomic dispatch, harmonic damages Grid Stability and Harmonic Mitigation System

28 Protects the power grid from solar storms and Electromagnetic Pulse (EMP ) threats SolidGround TM SCADA controls and monitoring Automated protection (with manual overrides) Reduces Harmful Harmonic Generation No Adjustment of protection relay settings required Total GIC system reduction Reduces VAR Consumption Lower Cost than Cap Banks, Series Caps and Uneconomic Dispatch Reduces stress on and protects equipment Stabilizes the Grid Grid Stability and Harmonic Mitigation System