In version 2.0, a typical starting time delay of 24ms is subtracted fromthe set trip time delay, so that the resulting trip time will take theinternal IED start time into consideration.25.3 Inverse characteristicsTable 959:ANSI Inverse time characteristicsFunction Range or value AccuracyOperating characteristic:( )1PAt B k tDefIæ öç ÷= + × +ç ÷ç - ÷è øEQUATION1249-SMALL V2 ENReset characteristic:( )21= ×-trt kIEQUATION1250-SMALL V1 ENI = Imeasured/Isetk = (0.05-2.00) in steps of 0.01 ANSI/IEEE C37.112 ,± 2.0% or ± 40 mswhichever is greaterANSI Extremely Inverse A=28.2, B=0.1217, P=2.0 ,tr=29.1ANSI Very inverse A=19.61, B=0.491, P=2.0 ,tr=21.6ANSI Normal Inverse A=0.0086, B=0.0185, P=0.02,tr=0.46ANSI Moderately Inverse A=0.0515, B=0.1140, P=0.02,tr=4.85ANSI Long Time Extremely Inverse A=64.07, B=0.250, P=2.0,tr=30ANSI Long Time Very Inverse A=28.55, B=0.712, P=2.0,tr=13.46ANSI Long Time Inverse A=0.086, B=0.185, P=0.02,tr=4.61MRK502052-UEN B Section 25Inverse time characteristics1253Technical manual
