OPERATING PRINCIPLES
GEK-106166E
DFF Digital Feeder Relay
9
GENERAL SETTINGS DESCRIPTION
•
RELAY STATUS
: The relay can be switched in or out of service (
NO SERV
/
IN SERV
)
•
FREQUENCY
: Defines the nominal frequency of the network ( 50 Hz / 60 Hz )
•
NOMINAL VOLTAGE
: Defines the secondary phase-phase Vac nominal voltage applied to the relay.
•
INHIBIT V
: The relay incorporates an inhibit voltage element with a user settable threshold
INHIBIT V
.
•
SEMICYCLES SET
: The DFF includes a counter that increments in semi cycles during an underfrequency
situation. For example 5 semi cycles of 50Hz is equivalent to 50ms delay. This acts as a time delay to filter
spurious variations in the input signal to the frequency unit. The counter is initially frozen if the frequency restores
and it is reset by the operation of the
SEMICYCLES RESET
counter. This counter activates the Frequency
Element pick up signal when the count exceeds the
SEMICYCLES SET
threshold.
•
SEMICYCLES RESET
: The DFF includes a counter that increments in semi cycles when the frequency restores.
This counter resets the
SEMICYCLES SET
counter when the count exceeds the
SEMICYCLES RESET
threshold.
•
PHASE VT RATIO
: Defines the ratio of the HV phase voltage transformer.
•
GROUND VT RATIO
: Defines the ratio of the HV zero sequence voltage transformer.
SETTINGS FOR EACH INDIVIDUAL FREQUENCY ELEMENT (for example 81 N1)
•
The
FUNCTION TYPE
setting adjusts the operation of the frequency unit as absolute frequency or rate of change
of frequency (
df/dt
).
•
The
81 PICKUP
is the pickup value for the unit if it is set as
FREQ
and for the underfrequency supervision
element if it is set as
df/dt
.
•
The
TIME DELAY
is the intentional time delay of the unit to produce a trip after pick up.
•
dF/dT
is the instantaneous value of the rate of change of frequency that will produce a trip if the
FUNCTION
TYPE
is set as
df/dt
, and the supervision elements have operated.
•
RESET TIME
is the time the frequency units maintain the tripping signal after the condition that caused the trip
has disappeared.
OPERATION IN FREQ MODE:
Select the setting
FUNCTION TYPE
as
FREQ
. (The setting value of
dF/dT
is now ignored). The operation time of
this unit will depend on the setting of
TIME DELAY
. The pickup will occur once the adjusted “number of semi-cycles”
expire, (common setting for all units), and the trip will take place when the time delay ends (note that tripping
conditions should persist during all the time delay).
OPERATION IN DF/DT MODE:
To adjust a unit as rate of change select the setting
FUNCTION TYPE
as
dF/dT
.
In order to issue a trip in this operating mode the frequency has to be lower than the adjusted value in setting
81
PICKUP
AND the rate of change of frequency must be more negative than the setting value of dF/dT.
Summary of Contents for Multilin DFF
Page 5: ...TABLE OF CONTENTS 4 DFF Digital Feeder Relay GEK 106166E ...
Page 25: ...EQUIPMENT CONFIGURATION 24 DFF Digital Feeder Relay GEK 106166E ...
Page 29: ...TECHNICAL CHARACTERISTICS 28 DFF Digital Feeder Relay GEK 106166E ...
Page 43: ...ACCEPTANCE TESTS 42 DFF Digital Feeder Relay GEK 106166E ...
Page 45: ...KEYPAD AND DISPLAY 44 DFF Digital Feeder Relay GEK 106166E ...
Page 60: ...FIGURES GEK 106166E DFF Digital Feeder Relay 59 10 FIGURES ...
Page 67: ...FIGURES 66 DFF Digital Feeder Relay GEK 106166E Figure 7 Panel Mounting for 19 rack models ...
Page 70: ...FIGURES GEK 106166E DFF Digital Feeder Relay 69 Figure 10 Dimensions Diagram for rack models ...
Page 71: ...FIGURES 70 DFF Digital Feeder Relay GEK 106166E Figure 11 Front View for 19 rack models ...
Page 72: ...FIGURES GEK 106166E DFF Digital Feeder Relay 71 Figure 12 Rear View for 19 rack model ...
Page 73: ...FIGURES 72 DFF Digital Feeder Relay GEK 106166E Figure 13 Front View for rack models B2213F3 ...
Page 74: ...FIGURES GEK 106166E DFF Digital Feeder Relay 73 Figure 14 Rear View for rack models B2213F2 ...