Power system protection

Protection engineering tools

Interactive calculators for relay setting and coordination studies on transmission and generation projects. Every input can be edited, and everything runs in the browser.

Overcurrent

IDMT Overcurrent Relay Simulator

Trip-time curves for up to four relays across a transformer, with fault current derived from the transformer data, coordination time intervals, cable and inrush overlays, and PDF and CSV export.

IEC 60255IEEE C37.112Coordination
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Transformer differential

Bias Characteristic Simulator

Compares the bias characteristics of two relays on a common per-unit base, tests operating points from measured phasors with vector-group compensation, and replays COMTRADE records.

87TVector groupsCOMTRADE
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Distance

Distance Reach and Power Swing Sheet

Zone reach criteria with adjacent lines and transformers, residual compensation, resistive reach, load encroachment and power swing blinders on the R/X diagram. Outputs a setting sheet for the relay engineer.

21 / 68 / 78GE L90ABB RED670
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