Includes settings for operation, reactive and resistive boundaries, various timers, base
settings for current levels and several others.
9.3.3.6
Automatic switch onto fault logic (PSOF)
Settings/Setting group N/Distance protection/AutomaticSOTF
Includes five settings. These are operation, rated current (IBase), rated voltage
(UBase), phase current threshold as a percentage of IBase and the phase voltage
threshold as a percentage of UBase.
9.3.4
Current protection
9.3.4.1
Overview
Under Current protection there are settings for Instantaneous phase overcurrent,
Phase overcurrent four step, Instantaneous residual overcurrent, Residual overcurrent
four step, Thermal overload with two time constants, Pole discordance and Breaker
failure. There are several instances of each function with parameter settings for rated
data, operation and many others. The thermal overload functions have temperature
threshold settings as well as many others necessary for adapting the function to a
particular application.
9.3.4.2
Instantaneous phase overcurrent protection (PIOC, 50)
Settings/Setting Group N/Current protection/InstPhaseOvercurrent(PIOC)
Displays three instances of IOC with five settable parameters per instance. Operation
mode, operate current multiplier, operation on or off, operate phase current level as
a percentage of Ibase, and Ibase itself are the settable parameters available here.
9.3.4.3
Four step phase overcurrent protection (POCM, 51/67)
Settings/Setting Group N/Current protection/PhaseOverCurrent4Step(POCM)
Displays three instances of TOC each with over 80 settings. The settings range from
base current and voltage settings to parameters for customer programmable curves.
9.3.4.4
Instantaneous residual overcurrent protection (PIOC, 50N)
Settings/Setting Group N/Current protection/InstResidualOverCurrent(PIOC)
Displays three instances of IEF with four settable parameters per instance. The
settable parameters are operation (On or Off), base setting for current magnitude, the
threshold current as a percentage of Ibase, and the multiplier for the current threshold
level.
Section 9
Read and change settings
RET 670
Operator's manual
1MRK504049-UEN rev. D
47