definite time delay. Thus, if only the inverse time delay is required, it isimportant to set the definite time delay for that stage to zero.26.3 Inverse characteristics IP15797-1 v2M12388-1 v21Table 687:ANSI Inverse time characteristicsFunction Range or value AccuracyOperating characteristic:( )= + ×-æ öç ÷ç ÷è ø1PAt B tdIEQUATION1651 V1 EN-USReset characteristic:( )= ×-21trt tdIEQUATION1652 V1 EN-USI = Imeasured/Iset0.10 ≤ td ≤ 3.001.5 x Iset ≤ I ≤ 20 x IsetANSI/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=4.6Section 26 1MRK 511 408-UUS AInverse time characteristics888 Phasor measurement unit RES670 2.2 ANSITechnical manual
