Identification...................................................................................... 63Function block................................................................................... 64Signals...............................................................................................64Basic part for LED indication module......................................................65Identification...................................................................................... 65Function block................................................................................... 65Signals...............................................................................................65Settings..............................................................................................66LCD part for HMI function keys control module...................................... 67Identification...................................................................................... 67Function block................................................................................... 67Signals...............................................................................................67Settings..............................................................................................67Operation principle..................................................................................68Local HMI...........................................................................................68Display..........................................................................................68LEDs.............................................................................................71Keypad......................................................................................... 71LED....................................................................................................73Functionality................................................................................. 73Status LEDs..................................................................................73Indication LEDs............................................................................ 73Function keys.....................................................................................82Functionality................................................................................. 82Operation principle....................................................................... 82Section 6 Differential protection.......................................................... 85Transformer differential protection..........................................................85Functionality ......................................................................................85Transformer differential protection, three winding T3WPDIF (87T)... 86Identification................................................................................. 86Function block.............................................................................. 87Signals..........................................................................................87Settings.........................................................................................88Monitored data..............................................................................90Operation principle............................................................................ 90Function calculation principles......................................................91Fundamental frequency differential currents................................ 92Differential current alarm.............................................................. 97Bias current.................................................................................. 98Table of contents2Technical manual
