GE D60 Instruction Manual page 126

5.3 SYSTEM SETUP
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 parame-
ter 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 50DD element is a sensitive current disturbance detector that detects any disturbance on the protected system. 50DD
is intended for use in conjunction with measuring elements, blocking of current based elements (to prevent maloperation as
a result of the wrong settings), and starting oscillography data capture. 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:
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 (
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UCT SETUP DISPLAY PROPERTIES
accordingly.
An example of the use of sources, with a relay with two CT/VT modules, is shown in the diagram below. A relay could have
the following hardware configuration:
INCREASING SLOT POSITION LETTER -->
CT/VT MODULE 1
CTs
This configuration could be used on a two winding transformer, with one winding connected into a breaker-and-a-half sys-
tem. 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.
5-42
ACTUAL
SOURCE 1
CURRENT PHASOR
_1
_2
_0
ACTUAL
SOURCE 2
CURRENT PHASOR
_1
_2
_0
ACTUAL
SOURCE 6
CURRENT PHASOR
_1
_2
_0
Figure 5–12: DISTURBANCE DETECTOR LOGIC DIAGRAM
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CURRENT CUT-OFF LEVEL
CT/VT MODULE 2 CT/VT MODULE 3
VTs not applicable
D60 Line Distance Relay
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
827092A3.CDR
) controls the sensitivity of the disturbance detector
5 SETTINGS
PROD-
GE Multilin