ABB RER620

Section 4 1MAC309294-MB F
Protection functions
190 RER620
Technical Manual
Figure 86: Functional module diagram (Three Phase trip mode)
Three Phase Mode
The following description holds good when three phase mode is chosen for the recloser.
The fundamental frequency component of the measured single-phase voltage is compared
to the set value of the Start (pickup) value setting phase-wise. If the measured value is
higher than the set value of the Pickup value setting, the level detector enables the phase
selection logic module. The Relative hysteresis setting can be used for preventing
unnecessary oscillations if the input signal slightly differs from the Pickup value setting.
After leaving the hysteresis area, the pickup condition has to be fulfilled again and it is not
sufficient for the signal to only return to the hysteresis area.
The Voltage selection setting is used for selecting phase-to-ground or phase-to-phase
voltages for protection.
For the voltage IDMT operation mode, the used IDMT curve equations contain
discontinuity characteristics. The Curve Sat relative setting is used for preventing
undesired operation.
Phase selection logic
If the fault criteria are fulfilled in the level detector, the phase selection logic detects the
phase or phases in which the fault level is detected. If the number of faulty phases match
with the set Num of start phases, the phase selection logic activates the timer.
Timer
Once activated, the timer activates the PICKUP(START) output. Depending on the value
of the set Operating curve type, the time characteristics are selected according to DT or
IDMT.
For a more detailed description of the IDMT curves and the use of the
Curve Sat Relative setting, see the General function block features section
in this manual.
For a detailed description of the voltage IDMT curves, see the General
function block features section in this manual.
V_A_AB
V_B_BC
V_C_CA
BLOCK
Phase
selection
logic
Level
detector
t
Timer
t
OPERATE
START
Blocking
logic