A BIEC99000054-3-en.vsdStrongsourceWeaksourceIEC99000054 V3 EN-USFigure 197: Initial condition for weak-end infeed15.5.3 Setting guidelines IP15042-1 v1M13933-4 v5The parameters for the current reversal and weak-end infeed logic for residualovercurrent protection function are set via the local HMI or PCM600.Common base IED values for primary current (IBase), primary voltage (UBase)and primary power (SBase) are set in a Global base values for settings functionGBASVAL.GlobalBaseSel: It is used to select a GBASVAL function for reference of basevalues.15.5.3.1 Current reversal M13933-6 v5The current reversal function is set on or off by setting the parameter CurrRev toOn or Off. Time delays shall be set for the timers tPickUpRev and tDelayRev.tPickUpRev is chosen shorter (<80%) than the breaker opening time, but minimum20 ms.tDelayRev is chosen at a minimum to the sum of protection reset time and thecommunication reset time. A minimum tDelayRev setting of 40 ms isrecommended.The reset time of the directional residual overcurrent protection (EF4PTOC) istypically 25 ms. If other type of residual overcurrent protection is used in theremote line end, its reset time should be used.The signal propagation time is in the range 3 – 10 ms/km for most types ofcommunication media. In communication networks small additional time delaysare added in multiplexers and repeaters. Theses delays are less than 1 ms perprocess. It is often stated that the total propagation time is less than 5 ms.When a signal picks-up or drops out there is a decision time to be added. Thisdecision time is highly dependent on the interface between communication andprotection used. In many cases an external interface (teleprotection equipment) isused. This equipment makes a decision and gives a binary signal to the protectiondevice. In case of analog teleprotection equipment typical decision time is in therange 10 – 30 ms. For digital teleprotection equipment this time is in the range 2 –10 ms.1MRK 511 401-UEN A Section 15Scheme communicationBay control REC670 2.2 IEC 449Application manual
