2.2.2 OVERFREQUENCY PROTECTION LOGIC
F>1 TripF>1 Trip
F>1 StatusF>1 Status
V00862
DT
F>1 StartF>1 Start
&
EnabledEnabled
F>1 SettingF>1 Setting
Freq Not FoundFreq Not Found
Averaging
F>1 Timer BlockF>1 Timer Block
All Poles DeadAll Poles Dead
1
FreqFreq
890
1370
1153
1159
1165
Figure 238: Overfrequency logic (single stage)
If the frequency is above the setting and not blocked, the DT timer is started and after this has timed out, the trip is
produced. If the frequency cannot be determined, the function is blocked.
2.2.3
APPLICATION NOTES
2.2.3.1 SETTING GUIDELINES
Following changes on the network caused by faults or other operational requirements, it is possible that various
subsystems will be formed within the power network. It is likely that these subsystems will suffer from a
generation/load imbalance. The "islands" where generation exceeds the existing load will be subject to
overfrequency conditions. Severe over frequency conditions may be unacceptable to many industrial loads, since
running speeds of motors will be affected. The overfrequency element can be suitably set to sense this
contingency.
Chapter 15 - Frequency Protection Functions P543i/P545i
414 P54x1i-TM-EN-1
To Next Page
Loading...
Need help?
General
