Section 9 Secondary system supervision9.1 Current circuit supervision CCSRDIF (87)9.1.1 IdentificationFunction description IEC 61850identificationIEC 60617identificationANSI/IEEE C37.2device numberCurrent circuit supervision CCSRDIF - 879.1.2 FunctionalityOpen or short circuited current transformer cores can cause unwanted operation of manyprotection functions such as differential, ground-fault current and negative-sequencecurrent functions.It must be remembered that a blocking of protection functions at an occurrence of open CTcircuit will mean that the situation will remain and extremely high voltages will stress thesecondary circuit.Current circuit supervision (CCSRDIF, 87) compares the residual current from a threephase set of current transformer cores with the neutral point current on a separate inputtaken from another set of cores on the current transformer.A detection of a difference indicates a fault in the circuit and is used as alarm or to blockprotection functions expected to give inadvertent tripping.9.1.3 Function blockANSI08000055-1-en.vsdCCSRDIF (87)I3P*BLOCKIREFFAILALARMANSI08000055 V1 ENFigure 86: CCSRDIF (87) function block1MRK 511 287-UUS A Section 9Secondary system supervision203Technical manual
