Time Delay; Blocking; Design - ABB RET650 Technical Manual

1MRK 504 135-UEN A
10.2.7.2
10.2.7.3
10.2.7.4
Technical manual
percent of the global parameter UBase. To avoid oscillations of the output START
signal, a hysteresis has been included.
BLOCK
freqNotValid
Frequency Comparator
f > StartFrequency
IEC09000033 V1 EN
Figure 106: Schematic design of overfrequency protection SAPTOF

Time delay

The time delay for SAPTOF is a settable definite time delay, specified by the setting
tDelay.
If the START condition frequency ceases during the delay time, and is not fulfilled
again within a defined reset time, the START output is reset.

Blocking

It is possible to block Over frequency protection (SAPTOF) 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 START and the TRIP outputs are blocked.

Design

The design of overfrequency protection SAPTOF is schematically described in
figure 106.
Frequency protection
BLOCK
OR
START
Definite Time Delay
TimeDlyOperate
TRIP
Section 10
BLKDMAGN
Start
&
Trip
Output
Logic
START
TRIP
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