6.3.6 Monitored dataTable 41:EFPIOC Monitored dataName Type Values (Range) Unit DescriptionIN REAL - A Residual current6.3.7 Operation principleThe sampled analog residual currents are pre-processed in a discrete Fourier filter(DFT) block. From the fundamental frequency components of the residual current, aswell as from the sample values the equivalent RMS value is derived. This currentvalue is fed to the Instantaneous residual overcurrent protection (EFPIOC). In acomparator the RMS value is compared to the set operation current value of thefunction (IN>>). If the residual current is larger than the set operation current a signalfrom the comparator is set to true. This signal will, without delay, activate the outputsignal TRIP.6.3.8 Technical dataTable 42:EFPIOC technical dataFunction Range or value AccuracyOperate current (1-2500)% of lBase ± 1.0% of Ir at I £ Ir± 1.0% of I at I > IrReset ratio > 95% -Operate time 20 ms typically at 0 to 2 x Iset -Reset time 30 ms typically at 2 to 0 x Iset -Critical impulse time 10 ms typically at 0 to 2 x Iset -Operate time 10 ms typically at 0 to 5x Iset -Reset time 40 ms typically at 5 to 0x Iset -Critical impulse time 2 ms typically at 0 to 5 x Iset -Dynamic overreach < 5% at t = 100 ms -6.4 Four step residual overcurrent protection, zero,negative sequence direction EF4PTOCSection 6 1MRK 511 287-UEN ACurrent protection92Technical manual
