Universal Arc Resistance Model Zagreb for EMTP

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Universal Arc Resistance Model Zagreb for
EMTP
Authors Sandra Hutter, HEP ODS d.o.o., DP
Elektra Zagreb, Croatia Ivo Ugleic, Faculty of
Electrical Engineering and Computing Zagreb,
Croatia Michael Muhr, Graz University of
Technology, Austria
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AC arc extinction in the case of short line fault

• after zero passing small post arc current

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Black box models

• mathematical description of the arc electrical
  behavior
• Cassie-Mayr arc equation
• Schwarz modification
• solved numerically with Euler method
• - sufficiently small time interval
  (P,tconst. )

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Benchmark circuit

• Time step has to be sufficiently small
• 60 Hz, Dt 10 ns

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Post zero arc currents

• Model ZAGREB Reference models
• TU Delft

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Arc voltage
Model ZAGREB Reference models
TU Delft
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Arc voltage detail
Reference models TU Delft
Model ZAGREB
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Air blast and SF6 circuit breaker

• Thermal period for SLF

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Air blast and SF6 circuit breaker

• air blast c. b. have longer thermal period

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Application

• Switching overvoltage analysis
• consecutive switching of two or more SF6 or air
  blast c. b.
• Calculation of VFTO in GIS
• during disconnector switching
• Chopping of small
• inductive currents

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Conclusion

• developed arc resistance model for EMTP
• black box model based on Cassie-Mayr arc equation
  
• model tested on a benchmark circuit
• simulation results match well with the referenced
  models

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Thank you!Viel Dank!