5.10.5 Parameters GUID-546BE3C2-EB4B-4877-92B1-A62C22782EC4 v1Table 92: Inverse time earth fault overcurrent function - parametersSignal DescriptionParSet4..1 Parameter for determining in which set of parameters a particular function isactive.CurrentInp Defines the CT input channel. All the current channels are available for selection.c-Setting Setting for the exponential factor determining the shape of the operatingcharacteristic according to BS 142 or for selecting the RXIDG characteristic.k1-Setting Tripping characteristic constantIStart Pick-up setting (initiates the tripping characteristic).tmin Definite minimum time of the tripping characteristic.NrOfPhases Number of phases evaluated for measurement:• 1: neutral current direct from an CT input• 3: neutral current derived internally from the three phasesIB-Setting Reference current to take account of discrepancies with respect to IN.BlockingInp I/P for the external blocking signal.• F: unused• T: function always blocked• xx: all binary I/P's (or O/P's of protection functions)Trip Tripping signalStart Pick-up signal5.10.6 Configuration GUID-7782BCDB-EEF4-4AE5-8B8A-204E8D180EFE v1Protection function enable IStartThe function starts to run when the current applied to the function exceeds the settingIStart.IStart is normally set to1.1 IB.Choice of tripping characteristic c-SettingThe shape of the IDMT characteristic is determined by the constant c.The standard IDMT characteristics according to BS 142 are:normal inverse: c = 0.02very inverse and long time earthfault:c = 1.00extremely inverse: c = 2.00Section 5 1MRK 505 406-UEN BBay protection functions170 Bay protection functions REB500Technical manual© Copyright 2019 ABB. All rights reserved
