ON IT Consolidated Edison’s Experience with On-line Monitoring and Mitigation of Geomagnetic Disturbances Gary R. Hoffman, Advanced Power Technologies Sam Sambasivan, Consolidated Edison Vincenzo Panuccio, Consolidated Edison Mypsicon, November 2016 1
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ON IT
Consolidated Edison’s Experience with On-line
Monitoring and Mitigation of Geomagnetic Disturbances
Gary R. Hoffman, Advanced Power TechnologiesSam Sambasivan, Consolidated Edison
Vincenzo Panuccio, Consolidated EdisonMypsicon, November 2016
1
ON IT
Agenda
2
• Overview of GIC Activities at Con Edison
• Selecting the vulnerable transformers
• GIC Monitoring according to IEEE Std. C57-163-2015
• GIC Modeling of 345 kV Autotransformers
• Results of Analysis
• Conclusion
ON IT
Selection of Vulnerable Transformers According to IEEE Std C57.163-2015
3
• Total susceptibility to effects of GIC is determined by:
– Transformer Design – Based Susceptibility
– GIC Level – Based Susceptibility
• Design – Based Susceptibility
– Category – A: Transformers not susceptible to effects of GIC
– Category – B: Transformers least susceptible to core saturation
– Category – C: Transformers susceptible to core saturation and structural parts overheating
– Category – D: Transformers susceptible to both core saturation as well as possible damaging windings and / or Structural parts overheating
• GIC – Level susceptibility divides transformers into 3 categories: Three ranges of GIC levels (High, Medium, and Low)
ON IT
Selection of Vulnerable Transformers at Con Edison
4
• Which Transformers to Monitor– Conducted review of 2012 EPRI Sunburst data
– Commissioned a CEATI study to rank transformers based on GIC susceptibility
– Conducted comparison of highest observed GIC levels at Con Edison and results given by GIC calculation study conducted by CEATI
– Selected transformers based on these results
ON IT
5
Location Core Design CEATI Relative Ranking(GIC)
Transformer 1 Shell Form 1
Transformer 2 Shell Form 2
Transformer 3 Shell Form 2
Transformer 4 Shell Form 3
Transformer 5 Shell Form 3
Transformer 6 Shell Form 4
Transformer 7 Shell Form 4
Transformer 8 Shell Form 5
Transformer 9 Shell Form 6
Transformer 10 Shell Form 5
Transformer 11 Shell Form 5
Transformer 12 Shell Form Not modeled in CEATI study
• GIC Susceptible Transformers
Selection of Vulnerable Transformers at Con Edison
ON IT
GIC Monitoring
6
• Why Monitor?– Provides the ability to see real time what is happening when GIC
events occur
– Continuous monitoring and operation response procedure is an effective and less costly alternative to both passive and active blocking schemes.
– Provides the gathering of data for post event analysis to help us better understanding system strengths and weaknesses during a GMD event
ON IT
GIC Monitoring
7
• Monitoring According to IEEE Std. C57.163-2105
─ Measure GIC of neutral current
─ Measure harmonics on bushing CTs
─ Deploy GIC or part-cycle core saturation detection
─ Place fiber optic temperature sensors at strategic locations on new and re-built transformers
─ Perform DGA of transformers when there is evidence of part-cycle core saturation at elevated levels of GIC
ON IT
GIC Monitoring
8
• GIC & Harmonics According to IEEE Std. C57.163-2105
─ GIC is quasi-dc that requires ultra low frequency measurement of GIC from X0, H0, Y0, or X0H0 bushing
─ Hall effect current sensors desensitized at power system frequency is recommended
─ Monitor current harmonics in three-phase transformers on the outer pahases
─ The magnitude of even current harmonics due to part-cycle core saturation dominate odd current harmonics1
1 US Patent 9,018,962 and Foreign Patents Pending
ON IT
GIC Monitoring
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• Typical GIC Waveform
-40
-30
-20
-10
0
10
20
30
40
50
GIC,
Amp
sADC
IEEE Std C57-163-2015™- Reprinted with permission from IEEE. Copyright IEEE 1983-2015. All rights reserved. Any comments or interpretations of the Material are the Author’s and do not represent the views of IEEE, its members or affiliates.
ON IT
GIC Monitoring
10
• Typical GIC Waveform
IEEE Std C57-163-2015™- Reprinted with permission from IEEE. Copyright IEEE 1983-2015. All rights reserved. Any comments or interpretations of the Material are the Author’s and do not represent the views of IEEE, its members or affiliates.
ON IT
GIC Monitoring
11
• Current Harmonic Order of Part-Cycle Core Saturation
IEEE Std C57-163-2015™- Reprinted with permission from IEEE. Copyright IEEE 1983-2015. All rights reserved. Any comments or interpretations of the Material are the Author’s and do not represent the views of IEEE, its members or affiliates.
ON IT
GIC Monitoring
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• Part-Cycle Core Saturation Detection on Three-phase Auto
ON IT
13
• How we Monitor?– Comprehensive GIC monitoring
device installed at all vulnerable transformers
– Device monitors:
– Temperature
– Load Current
– Harmonics
– DC Neutral Current
– Device collects data and generates alarms that operations uses to determine system status and take action during GIC events
• DC Model of High Voltage Transmission System (GIC Network Model)
• Model Validation – Rotate E-Field from 0o to 180o
– Compare simulated neutral currents to measurements
GIC Modeling
ON IT
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PT-1 max E-field estimated by year
Max
E-fi
eld
by y
ear f
or v
ario
us re
gion
s (m
V/km
)
• Study Database– NYISO planning model, load flow base case modified for Con Edison peak
load– Geographic Long.=74W, Geographic Lat.=41N (Mag. Lat=48) corresponds to
Piedmont (PT-1) region from US Geological Survey (USGS) – Conductivity High for PT-1 Region– Geo-electric fields (E-field) since 1985 less than 2V/km (USGS)
GIC Modeling
ON IT
• Transmission Perf. During GMD Draft TPL-007-1 standard:
Epeak =8 × 𝛼 × 𝛽 (V/km)
Epeak =8 × 0.3 × 1.17 V/km= 2.28 V/km
8 V/km is a reference peak geoelectric field amplitude derived from
statistical analysis of historical magnetometer data
𝛼 scaling factors to account for local geomagnetic latitude
𝛽 scaling factors to account for local earth conductivity
19
GIC Modeling
ON IT
• GIC Flows Analysis– Simulation done at 1 V/m electric field
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TransformerNeutral GIC Flows in Ampere for Different Electric Field