Deif PPM 300 - Busbar] Under-Frequency (ANSI 81 U)

Controller type Inhibit(s)
SHAFT generator • Shaft breaker open
SHORE connection • Shore breaker open
3.5.5 [Busbar] under-frequency (ANSI 81U)
Protection IEC symbol (IEC60617) ANSI (IEEE C37.2) IEC 61850 Operate time
Under-frequency f<, f<< 81U PTUF < 50 ms
The alarm response is based on the highest fundamental frequency (based on phase voltage),
from the busbar. This ensures that the alarm only activates when all of the phase frequencies
are below the set point.
For the BUS TIE breaker controller, this is the frequency measured on busbar B.
Set
point
Value
time
Delay
Configure the parameters under Configure > Parameters > [Busbar] > Frequency protections > Under-frequency #, where # is
1 or 2.
Table 3.62
Default parameters
Parameter Range Busbar under-frequency 1 Busbar under-frequency 2
Set point 80 to 100 % of nominal frequency 96 % 93 %
Delay 0.00 s to 1 h 10.00 s 5.00 s
Enable Not enabled, Enabled Enabled Enabled
Latch Not enabled, Enabled Not enabled Enabled
Action Warning Trip [Breaker]*
*Note: For the EMERGENCY genset controller, this alarm action trips the tie breaker to the main busbar. For other controllers: The
controller trips the breaker to the equipment that it controls.
Table 3.63
Default inhibits
Controller type Inhibit(s)
GENSET
• Generator breaker open
• ACM wire break
EMERGENCY genset
• Generator breaker open
• Tie breaker open
• EDG handling blackout
SHAFT generator
• Shaft breaker open
• ACM wire break
SHORE connection
• Shore breaker open
• ACM wire break
BUS TIE breaker • ACM wire break
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