GE D60 - Page 236

5-102 D60 Line Distance Protection System GE Multilin
5.4 SYSTEM SETUP 5 SETTINGS
5
User selection of AC parameters for comparator elements:
CT/VT modules automatically calculate all current and voltage parameters from the available inputs. Users must select the
specific input parameters to be measured by every element in the relevant settings menu. The internal design of the ele-
ment specifies which type of parameter to use and provides a setting for source selection. In elements where the parameter
may be either fundamental or RMS magnitude, such as phase time overcurrent, two settings are provided. One setting
specifies the source, the second setting selects between fundamental phasor and RMS.
AC input actual values:
The calculated parameters associated with the configured voltage and current inputs are displayed in the current and volt-
age sections of actual values. Only the phasor quantities associated with the actual AC physical input channels will be dis-
played here. All parameters contained within a configured source are displayed in the sources section of the actual values.
DISTURBANCE DETECTORS (INTERNAL):
The disturbance detector (ANSI 50DD) element is a sensitive current disturbance detector that detects any disturbance on
the protected system. The 50DD function is used directly in some elements in the relay, for example VT Fuse Failure detec-
tor or Fault Report. It can also be used to supervise current-based elements to prevent maloperation as a result of the
wrong settings or external CT wiring problem. A disturbance detector is provided for each source.
The 50DD function responds to the changes in magnitude of the sequence currents. The disturbance detector scheme
logic is as follows:
Figure 5–25: DISTURBANCE DETECTOR LOGIC DIAGRAM
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 (PROD-
UCT SETUP  DISPLAY PROPERTIES  CURRENT CUT-OFF LEVEL) controls the sensitivity of the disturbance detector
accordingly.
827092A3.CDR
SOURCE 1
CURRENT PHASOR
PRODUCT SETUP/DISPLAY
PROPERTIES/CURRENT
CUT-OFF LEVEL
PRODUCT SETUP/DISPLAY
PROPERTIES/CURRENT
CUT-OFF LEVEL
PRODUCT SETUP/DISPLAY
PROPERTIES/CURRENT
CUT-OFF LEVEL
SOURCE 2
CURRENT PHASOR
SOURCE 6
CURRENT PHASOR
ACTUAL
SETTING
SETTING
SETTING
ACTUAL
ACTUAL
FLEXLOGIC OPERAND
FLEXLOGIC OPERAND
FLEXLOGIC OPERAND
I_1
I_1
I_1
SRC 1 50DD OP
SRC 2 50DD OP
SRC 6 50DD OP
I_2
I_2
I_2
I_0
I_0
I_0
OR
OR
OR
Where ’ is 2 cycles oldI
Where ’ is 2 cycles oldI
Where ’ is 2 cycles oldI
II_1 - _1’ >2*CUT-OFF
II_1 - _1’ >2*CUT-OFF
II_1 - _1’ >2*CUT-OFF
II_2 - _2’ >2*CUT-OFF
II_2 - _2’ >2*CUT-OFF
II_2 - _2’ >2*CUT-OFF
II_0 - _0’ >2*CUT-OFF
II_0 - _0’ >2*CUT-OFF
II_0 - _0’ >2*CUT-OFF