Time Delay - ABB REC650 ANSI Technical Manual

Section 8
Frequency protection
8.2.7.2
8.2.7.3
8.2.7.4
198

Time delay

The time delay for SAPTOF (81) is a settable definite time delay, specified by the setting
tDelay.
If the PICKUP condition frequency ceases during the delay time, and is not fulfilled again
within a defined reset time, the PICKUP output is reset.
Blocking
It is possible to block Over frequency protection (SAPTOF, 81) completely, by binary
input signals or by parameter settings, where:
BLOCK: blocks all outputs
If the measured voltage level decreases below the setting of MinValFreqMeas in the
preprocessing function both the PICKUP and the TRIP outputs are blocked.
Design
The design of overfrequency protection SAPTOF (81) is schematically described in
figure 82.
BLOCK
BLKTRIP
Comparator
V < IntBlockLevel
Voltage
Frequency Comparator
f > PuFrequency
ANSI05000735 V1 EN
Figure 83: Schematic design of overfrequency protection SAPTOF (81)
BLOCK
OR
Time integrator
PICKUP
Definite Time Delay
TimeDlyOperate
TRIP
TimeDlyReset
1MRK 511 287-UUS A
BLKDMAGN
Pickup
&
Trip
Output
Logic
PICKUP
TRIP
en05000735_ansi.vsd
Technical manual