DEMA DPM 400 D - U - under Frequency Protection

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4.3.4.1 81U – Under Frequency Protection
The overvoltage protection settings are located Menu> Protection Settings> Frequency
Protection Settings> Under Frequency Protection
Working principle; The measured frequency value is the activation of the protection when the
assigned protection falls below the threshold. The time characteristic is DMT (constant time)
characteristic.
Directional phase overcurrent protection is indicated by f<, f<<, f<<<, f<<<<, f<<<<<,
f<<<<<< in IEC 60617 Standards; PIUF_1, PIUF_2, PIUF_3, PIUF_4, PIUF_5 ve PIUF_6 in
IEC 61850; 81-U-1, 81-U-2, 81-U-3, 81-U-4, 81-U-5 ve 81-U-6 in IEEE/ANSI Standards
Under Frequency Protection
IEC 61850
IEC 60617
IEEE-ANSI
-1
PIUF_1
f<
81U-I-1
-2
PIUF_2
f<<
81U-I-2
-3
PIUF_3
f<<<
81U-I-3
-4
PIUF_4
f<<<<
81U-I-4
-5
PIUF_5
f<<<<<
81U-I-5
-6
PIUF_6
f<<<<<<
81U-I-6
Under Frequency Protection Function Symbols
The menu view is as follows. The menu consists of five lines.