GE D30 Instruction Manual page 248

SYSTEM SETUP
5
The disturbance detector responds to the change in currents of twice the current cut-off level. The default cut-off threshold
is 0.02 pu; thus by default the disturbance detector responds to a change of 0.04 pu. The metering sensitivity setting
(
PRODUCT SETUP  DISPLAY PROPERTIES  CURRENT CUT-OFF LEVEL
accordingly.
5.5.3.4 Example for use of sources
An example of the use of sources is shown in the following figure. A relay can have the following hardware configuration:
This configuration can be used on a two-winding transformer, with one winding connected into a breaker-and-a-half
system. The following figure shows the arrangement of sources used to provide the functions required in this application,
and the CT/VT inputs that are used to provide the data.
5-116
Figure 5-47: Disturbance detector logic
ACTUAL
SOURCE 1
CURRENT PHASOR
_1
_2
_0
ACTUAL
SOURCE 2
CURRENT PHASOR
_1
_2
_0
ACTUAL
SOURCE 6
CURRENT PHASOR
_1
_2
_0
SETTING
PRODUCT SETUP/DISPLAY
PROPERTIES/CURRENT
CUT-OFF LEVEL
_1 - _1' >2*CUT-OFF FLEXLOGIC OPERAND
_2 - _2' >2*CUT-OFF
OR SRC 1 50DD OP
_0 - _0' >2*CUT-OFF
Where ' is 2 cycles old
SETTING
PRODUCT SETUP/DISPLAY
PROPERTIES/CURRENT
CUT-OFF LEVEL
_1 - _1' >2*CUT-OFF FLEXLOGIC OPERAND
_2 - _2' >2*CUT-OFF SRC 2 50DD OP
OR
_0 - _0' >2*CUT-OFF
Where ' is 2 cycles old
SETTING
PRODUCT SETUP/DISPLAY
PROPERTIES/CURRENT
CUT-OFF LEVEL
_1 - _1' >2*CUT-OFF
FLEXLOGIC OPERAND
_2 - _2' >2*CUT-OFF OR SRC 6 50DD OP
_0 - _0' >2*CUT-OFF
Where ' is 2 cycles old
) controls the sensitivity of the disturbance detector
D30 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 5: SETTINGS
827092A3.CDR