Voltage Units - GE Multilin DFF Instruction Manual

The DFF has 3 voltage units.
Inhibit voltage unit :
This unit supervises the phase voltage used for frequency calculation (phase B, of ABC). This unit is adjusted in the
GENERAL SETTINGS menu as described above. It is set as a percentage of the nominal voltage. The range goes
from 40 to 110 % of the nominal voltage (also adjustable). If the voltage measured in phase B goes below the setting,
all frequency units will be inhibited.
Undervoltage unit :
This unit measures phase B voltage. The settings are as follows:
• The 27P PICKUP setting is the voltage operating value. If phase B measured voltage value goes below this
setting, the unit picks up.
• The TIME DELAY 27P setting is the associated time delay for the undervoltage unit. The unit's trip takes place
only after this time expires, taking into account that the voltage level must be lower than the setting during the
course of the time delay.
• The RESET TIME 27P setting is the time that the unit maintains the tripping contacts closed once the trip
command has been issued and the undervoltage condition has disappeared.
Overvoltage units :
This unit measures phase B voltage. The settings are as follows:
• The PICKUP 59P setting is the voltage operating value. If phase B measured voltage value goes above this
setting the unit picks up.
• The TIME DELAY 59P setting is the associated time delay for the overvoltage unit. The trip takes place only after
this time expires. The voltage level must be higher than the setting during the course of the time delay.
• The RESET TIME 59P setting is the time that the unit maintains the tripping contacts closed once the trip
command has been issued and the overvoltage condition has disappeared.
10
OPERATING PRINCIPLES
Name
27P PICKUP 20.00 – 110.00 Vac
TIME DELAY 27P
RESET TIME 27P
Name
50.00 – 220.00 Vac
PICKUP 59P
TIME DELAY 59P
RESET TIME 59P
DFF Digital Feeder Relay
Limits Default
50 Vac
0.00 - 30.00 s 5 s
0 - 1200 s 0 s
Limits Default
80 Vac
0.00 – 30.00 s 5 s
0.00 – 30.00 s 0 s

2.1.2 VOLTAGE UNITS

Step
0.01 Vac
0.01 s
1 s
Step
0.01 Vac
0.01 s
0.01 s
GEK-106166E