1MRS751802-MUM REX 521123Protection RelayTechnical Reference Manual, Standard ConfigurationsFig. 7.4.1.-1 Function block symbol of CB wear7.4.2. TCS1The trip-circuit supervision function block TCS1 does not perform the supervisionitself but it is used as an aid for configuration. The functional part belongs mainly tothe self-supervision tasks of the PS_ card.Fig. 7.4.2.-1 Function block symbol of TCS17.4.3. MCS 3IThe supervision function block MCS 3I detects interruptions in energizing currentcircuits. The function block supervises the energizing circuits by comparing themeasured phase currents. If one or two phase currents exceed the setting “Highlimit”, while the measured phase current in the remaining one or two phases is belowthe setting “Low limit”, the output ALARM is activated after the adjustable alarmdelay.The function block is disabled if all input currents are below the setting “Low limit”.The ALARM output will reset automatically when the fault disappears.The phase current supervision function block operates on the numerically calculatedfundamental frequency component of the phase currents.Fig. 7.4.3.-1 Function block symbol of MCS 3I7.4.4. MCS 3UThe supervision function block MCS 3U detects interruptions in energizing voltagecircuits. The user can select three-phase or two-phase operation. The function blockcan also be set out of use by means of the parameter.OPENBINOPENBINCLOSEALARMCB wearTCSSTATEBS ALARMTCS1ALARMMCS 3I
