11.2.2 Functionality SEMOD113820-4 v12The aim of the fuse failure supervision function (FUFSPVC) is to block voltagemeasuring functions at failures in the secondary circuits between the voltagetransformer and the IED in order to avoid inadvertent operations that otherwisemight occur.The fuse failure supervision function basically has three different detectionmethods, negative sequence and zero sequence based detection and an additionaldelta voltage and delta current detection.The negative sequence detection algorithm is recommended for IEDs used inisolated or high-impedance earthed networks. It is based on the negative-sequencequantities.The zero sequence detection is recommended for IEDs used in directly or lowimpedance earthed networks. It is based on the zero sequence measuring quantities.The selection of different operation modes is possible by a setting parameter inorder to take into account the particular earthing of the network.A criterion based on delta current and delta voltage measurements can be added tothe fuse failure supervision function in order to detect a three phase fuse failure,which in practice is more associated with voltage transformer switching duringstation operations.11.2.3 Function block M13678-3 v9FUFSPVCI3P*U3P*BLOCKCBCLOSEDMCBOPDISCPOSBLKTRIPBLKZBLKU3PHDLD1PHDLD3PHSTDISTDIL1STDIL2STDIL3STDUSTDUL1STDUL2STDUL3IEC14000065-1-en.vsdIEC14000065 V1 EN-USFigure 136: FUFSPVC function block1MRK 505 394-UEN A Section 11Secondary system supervisionLine differential protection RED650 2.2 IEC 287Technical manual
