Professional protection relay testing calculator implementing IEEE C37. Calculate pickup values, timing curves, coordination time intervals (CTI), and test injection currents for overcurrent (50/51), differential (87), distance (21), and. This technical report refers to the electrical protections of all 132kV switchgear. All calculations are based on the available documentation/ information. These settings may be revaluated during the commissioning, according to actual and/or measured values. In. Protection relays employ a wide range of configurable parameters to identify defects & trip the breaker in a controlled & selected manner. TSM – Time. LAY S TTIN LAY SETTIN of CT groups fCalculate cable sizes quickly and accurately for various electrical installations. dk is Denmark's transmission system oper-ator.