Zone Selective Interlock - ZSI

Zone Selective Interlock - ZSI

Zone Selective Interlock Modeling & Evaluation

ZSI Scheme for Protective Device Evaluation & Arc Flash Mitigation Technique
Circuit Breaker Zone Selective Interlock (ZSI) capability in ETAP evaluates, verifies, and confirms the operation and selectivity of the ZSI scheme for various types of faults for Star Automated Protection & Selective studies and Arc Flash analysis.
Zone Selective Interlock - ZSI
  • Improve Safety & Minimize Equipment Damage
  • Validate ZSI Mitigation Technique & Scenarios
  • Intuitive & Graphical Zone Selective Interlocking
  • Fast & Efficient Modeling of ZSI Settings

Key Features

  • Consideration of ZSI scheme for Arc Flash analysis & mitigation technique 
  • Simulation & verification of tripped ZSI element via Star SQOP
  • Evaluation of ZSI Scheme in Star-Auto Evaluation
  • Compliance with NEC 240.87
  • Evaluate & compare ZSI performance
  • Manufacturer specific ZSI schemes per device
  • Simulate ZSI operation for various fault types
  • Display of Restrained and Unrestrained TCC curves
  • Model any interlock wiring scheme
  • Fast & efficient modeling of CBs & zone based interlock wiring
ZSI SQOP Summary Report Narrow
ZSI Device Settings Report wComparison


  • ZSI enforced or adjustable settings
  • ZSI logic modeling for Solid State Trip (SST) devices
  • Supports delay bands & thresholds
  • Phase & Ground zone interlock modeling
  • Short-Time, Instantaneous & Ground fault ZSI
  • Simplified user-defined modeling capability
  • V&V Library includes Manufacturer specific breakers with ZSI capabilities
  • Device settings report with ZSI settings in different formats
  • Comparison of ZSI device settings in Base and Revision data
  • Simulation comparison report with or without ZSI
  • Enable global ZSI feature via Study Case
  • Enable individual circuit breaker ZSI
  • Plot Restrained & Unrestrained TCC curves
  • Device settings report for adjustable ZSI elements
  • Star Auto-Evaluation graphical & tabular reports for ZSI what-if scenarios



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