ABB RER620 Technical Manual page 206

Section 4
Protection functions
200
Single Phase Mode
V_A_AB
detector
BLOCK
Figure 91: Functional module diagram (Single Phase)
The following description holds good when single 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. 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.
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.
Timer
Once activated, the timer activates the respective phase PICKUP(ST_A_AB) as shown
typically above for respective phase output as well as the common 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 detailed description of the voltage IDMT curves, see the General
function block features section in this manual.
When the operation timer has reached the value set by Trip delay time in the DT mode or
the maximum value defined by the IDMT, the TRIP (OPR_A_AB) for respective phase as
well as the common the OPERATE output are activated.
Level
Blocking
logic
1MAC309294-MB F
Timer
OPR_A-AB
t
t
ST_A_AB
Technical Manual
RER620