Geomagnetic Disturbance Power System Study in Maine

Transcription

1 Geomagnetic Disturbance Power System Study in Maine Maine IEEE Joint Chapter PES/IAS Technical Meeting 7/22/2015 Presenter: Justin Michlig, PE

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4 Overview NERC/FERC updates State of Maine Legislative updates Geomagnetic Disturbance (GMD) Theory GMD Power Flow data requirements Results of CMP GMD analysis Future Steps

5 NERC Standard TPL Applicability: Planning Coordinator Transmission Planner Transmission Owner Generator Owner Scope of facilities: Facilities operated or connected at 200+ kv Specifically transformers with a 200+ kv grounded winding are included

6 NERC Standard TPL High Level Summary: R1: Maintain Models for analysis R2: Run GMD Assessments every 5 years on peak and Off-Peak models Including reactive power device and other transmission facility contingences R3: If performance not acceptable, create Corrective Action Plan(s) R4: Must have criteria for acceptable steady state voltage R5: Coordinate responsibilities between PC and TP R6: Distribute assessment to neighbors R7: TO&GO to assess thermal impact to transformers R8: TO&GO to provide thermal assessment to PC and TP

7 NERC/FERC Updates FERC/NERC GMD Rulemaking activity: FERC Order 779: May 16, 2013 Directs NERC to develop GMD standards for Operations and Planning FERC Process started with Oct. 18, 2012 Notice of Proposed Rulemaking (NOPR) NERC GMD Taskforce scope started in 2010 FERC Order 797: June 19, 2014 Approves EOP Enforceable Date April 1, 2015 May 14, 2015 NOPR to approve TPL In addition send it back to NERC for edits Increase field strength to be tested Shorten implementation time if possible Enforceable date: TBD

8 Maine GMD Progress MPUC Docket: Started with LD 131 via resolve Report delivered to PUC & passed onto Legislature Jan 20, 2014 This report gathered pertinent documentation on past GMD and EMP events highlighting potential mitigation technologies. No tools available to quantify system impacts Continued in 2014 after PUC request to acquire software and perform analysis Results delivered to PUC end of 2014 and passed to Legislature 2014 Maine GMD/EMP Impacts Assessment LD 1363 Efforts to require installation of mitigation technologies and liability transferred to utilities Did not pass

9 GMD Planning Study Model the Transmission system Calculate the Geomagnetic Storm s Geoelectric intensity to be modeled Run a Geomagnetic Induced Current (GIC) DC power flow calculation Incorporate the DC results into an AC power flow simulation Apply contingencies and review for system deficiencies

10 DC GIC Theory - Voltages induced on the power system are calculated by geographic location and field intensity. - DC Resistance form lines, transformers, shunts, and other devices are utilized to construct the impedance network Figure 1 from K. Patil, Modeling and Evaluation of Geomagnetic Storms in the Electric Power System, DIGRE Used with Permission.

11 DC GIC Theory - GMD event casts a Geoelectric Field over the power system creating a DC current flow in the AC transmission system - Greatest impact while the Geoelectric Field is parallel to transmission line N Sub 1 Sub 2 DC Induced Voltage DC Induced Voltage

12 GIC Specific Data Data required in addition to traditional Steady State model: Geolocation (ex , ) Ground Grid Impedance Transformer * DC Resistance K Factor [4] Winding Connections Transformer core type NERC Benchmark Geoelectric Field intensity calculation* Other devices with low DC resistance Path *Additional detail on following slide

13 Transformer DC Data Auto Transformer Data Sheet Examples High Side Winding tested to ground in mω. Chose a phase or average value in Ω. Model value =.276 Ω Old Test reports are not easy to read and may be reported in total resistance. Divide total impedance by 3. Model value =.344 Ω

14 Transformer K Factor The K Factor Relates Effective GIC through the transformer to var consumption/additional losses 500 kv 345 kv Three Phase Shell form Single Phase (Separate Cores) Three Phase Three Legs Three Phase Five Legs Example 345 kv Grounded Auto Mvar Loss Calculation K factor Effective GIC Mvar A 20 Three Phase Seven Legs

15 NERC Reference GMD peak = 8 (V/km) peak = FERC NOPR directs NERC to update value Benchmark geoelectric field magnitude at System location Factor adjustment for geomagnetic latitude Factor adjustment for regional earth conductivity model

16 Lookup β Condensed Geoelectric Field Scaling Factors USGS Earth Model (β) AK1A 0.56 AK1B 0.56 AP FL NE PT SL BOU 0.28 FBK 0.56 PRU 0.21 Physiographic Regions of the Continental United States Figure 6 from NERC GIC Application Guide 2013

17 Calculation of α.001 e L L Geomagnetic North Latitude N N.6979 Geophysical Geomagnetic α N N.4169

18 Example Benchmark Field Calculation peak = 8 (V/km) FERC NOPR directs NERC to update value.001 e L L Geomagnetic North Latitude Geomagnetic conversion Latitude α Benchmark Field in Maine Northern ME 56.95N V/km Southern ME 52.46N V/km What does this calculation give me again? Electric Field to use in GIC power flow calculation Conservative value used in Maine 2014 study

19 Maine GMD Study Specifics Scope: Includes a GIC model within the Maine transmission system (a few buses into NB and NH) Focuses on 200+ kv Analyze Geoelectric fields from 4.53 V/km to 29 V/km in Maine Discuss system improvements and cost: Possible replacement of electromechanical relays Possible upgrades to capacitor banks to improve 5 min recovery time

20 2014 CMP GMD Analysis Review the transmission system per NERC GMD Planning Guide Establish the worst orientation of the Geoelectric Field Report the Effective GIC flows in transformers Report system impact to voltages

21 GMD Field Orientation PU Voltage vs. Geoelectric Field Orientation Shunt Switching_Chester Offline w/ Step-up out PU Voltage Entire Study Area State of Maine Degrees

22 GMD Field Orientation PU Voltage vs. Geoelectric Field Orientation Shunt Switching_Chester Offline w/ Step-up out Entire Study Area State of maine

23 Results from GMD field orientation effects match the orientation of the transmission in Maine. 23

24 CMP Results Mvar Transformer Mvar Consumption vs. Geoelectric Field 88 Chester SVC 18/345 kv Yarmouth GSU 22/345 kv #4 Keene Road GSU 115/345 kv Orrington 345/115 kv #1 Orrington 345/115 kv #2 South Gorham 345/115 kv #1 South Gorham 345/115 kv #2 Mason 345/115 kv #1 Macguire Road 345/115 #1 Keene Road 345/115 kv #1 Coopers Mill 345/115 kv #3 Surowiec 345/115 kv # V/km Geoelectric Field Albion Road 345/115 #1 Larrabe Rd 345/115 #1

25 CMP Results 1.04 Maine 345 kv Transmission Voltage vs Geoelectic Field V PU CHESTER SVC ORRINGTON COOPERS MILL RAVEN FARM MAINE YANKEE SUROWIEC YARMOUTH SOUTH GORHAM BUXTON MASON ALBION ROAD LARRABEE RD MAGUIRE ROAD KEENE ROAD V/km Geoelectric Field

26 CMP Results Reactive Reserves vs. Geoelectric Field Mvar 800 Online Capacitive Reactive Devices Total Installed Capacitive Reactive Devices V/km *Excludes Generator Reactive Capability, which is a significant source of reactive power

27 GMD Field Orientation Effective GIC A/phase for Maine transformers Degree Amp Max 4.53 V/km 14 V/km 20 V/km 23.5 V/km 29 V/km NERC 1 in 100 year Benchmark Study team assumed 1 in 50 year event Study team assumed 1 in 100 year event Study team assumed 1 in 200 year event Study team assumed 1 in 500 year event 2 winding delta - wye Chester SVC 18/345 kv Yarmouth GSU 22/345 kv # winding Auto Xfmrs Keene Road GSU 115/345 kv Orrington 345/115 kv # Orrington 345/115 kv # South Gorham 345/115 kv #1[1] South Gorham 345/115 kv # Mason 345/115 kv # Macguire Road 345/115 # Keene Road 345/115 kv # Coopers Mill 345/115 kv # winding Auto xfmrs Surowiec 345/115 kv # Albion Road 345/115 # Larrabee Rd 345/115 #

28 CMP Results Transformer Effective GIC using Each transformers most Impactful Geoelectric Field Angle Chester SVC 18/345 kv Yarmouth GSU 22/345 kv #4 Keene Road GSU 115/345 kv Orrington 345/115 kv #1 Effective GIC A/Phase Orrington 345/115 kv #2 South Gorham 345/115 kv #1 South Gorham 345/115 kv #2 Mason 345/115 kv #1 Macguire Road 345/115 #1 Keene Road 345/115 kv #1 Coopers Mill 345/115 kv #3 100 Surowiec 345/115 kv # Geoelectric Field Magnitude V/km Albion Road 345/115 #1 Larrabe Rd 345/115 #1

29 CMP Assumptions Change Results PU Voltage vs. Geoelectric Field 15V/km Entire Study Area State of maine

30 CMP Assumptions Change Results PU Voltage vs. Geoelectric Field 15V/km_No Shunt Switching_Chester Offline w/ Step-up in-service Entire Study Area State of maine

31 Maine Analysis Results Voltage performance of the Maine transmission system was very good Worst GMD storm angle ~88 degrees Each transformer had different angles which excited them the most Only Chester above 75 A/phase GIC recommended for thermal screening a 8 V/km benchmark event At 29 V/km field tested 8 transformers above thermal screening threshold

32 Not Covered But Important Harmonic Analysis May cause unintended tripping, but newer relays can filter No great method found to analyze GMD Harmonic effects

33 Maine Analysis Prospective Monitoring Chester Neutral current since 1991 GIC has been present and the power system has had voltage changes due to it Peak GIC neutral flow of 98 A (~33A/phase) Simulations of 75 A/phase during benchmark 8 V/km Capacitors, SVC Filters, and potential UPS functionality issue during events No customer outages No associated customer equipment damage reported

34 Maine Analysis Next Steps Reassemble previous study team Perform recommended thermal assessments of transformers Scope GMD monitoring for installation

35 Questions? 35

36 References [1] NERC GMD Project Page TPL GMD Task Force Planning Guide Benchmark Geomagnetic Disturbance Event Description Thermal Screening Criterion White Paper Transformer Thermal Impact Assessment White Paper Application Guide [2] Geomagnetic Location Calculator - [3] R. Horton, D. Boteler, T.J. Overbye, R. Pirjola, and R.C. Dugan, A Test Case for the Calculation of Geomagnetically Induced Currents, IEEE Transactions on Power Delivery, Vol. 27, No. 4, October 2012, pages [4] X. Dong, Y. Liu, J. G. Kappenman, Comparative Analysis of Exciting Current Harmonics and Reactive Power Consumption from GIC Saturated Transformers, Proceedings IEEE, 2001, pages [5] K. Patil, Modeling and Evaluation of Geomagnetic Storms in the Electric Power System, C4-306, CIGRE, 2014