GE T35 Instruction Manual page 206

5.4 SYSTEM SETUP
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 (

UCT SETUP DISPLAY PROPERTIES
5
accordingly.
EXAMPLE USE OF SOURCES:
An example of the use of sources is shown in the diagram below. A relay could have the following hardware configuration:
INCREASING SLOT POSITION LETTER -->
CT/VT MODULE 1
8 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.
5-72
ACTUAL
SOURCE 1
CURRENT PHASOR
I_1
I_2
I_0
ACTUAL
SOURCE 2
CURRENT PHASOR
I_1
I_2
I_0
ACTUAL
SOURCE 6
CURRENT PHASOR
I_1
I_2
I_0
Figure 5–18: DISTURBANCE DETECTOR LOGIC DIAGRAM

CURRENT CUT-OFF LEVEL
CT/VT MODULE 2 CT/VT MODULE 3
4 CTs, 4 VTs 4 CTs, 4 VTs
F 1
DSP Bank
F 5
Source 3
U 1
Volts Amps
V
V
Volts Amps
M 1
Source 4
M 1
M 5
Figure 5–19: EXAMPLE USE OF SOURCES
T35 Transformer Protection System
SETTING
PRODUCT SETUP/DISPLAY
PROPERTIES/CURRENT
CUT-OFF LEVEL
I I
FLEXLOGIC OPERAND
_1 - _1' >2*CUT-OFF
I I
_2 - _2' >2*CUT-OFF
OR SRC 1 50DD OP
I I
_0 - _0' >2*CUT-OFF
I
Where ' is 2 cycles old
SETTING
PRODUCT SETUP/DISPLAY
PROPERTIES/CURRENT
CUT-OFF LEVEL
I I FLEXLOGIC OPERAND
_1 - _1' >2*CUT-OFF
I I
SRC 2 50DD OP
_2 - _2' >2*CUT-OFF OR
I I
_0 - _0' >2*CUT-OFF
I
Where ' is 2 cycles old
SETTING
PRODUCT SETUP/DISPLAY
PROPERTIES/CURRENT
CUT-OFF LEVEL
I I
FLEXLOGIC OPERAND
_1 - _1' >2*CUT-OFF
I I
_2 - _2' >2*CUT-OFF OR SRC 6 50DD OP
I I
_0 - _0' >2*CUT-OFF
I
Where ' is 2 cycles old
827092A3.CDR
) controls the sensitivity of the disturbance detector
Source 1 Source 2
Amps Amps
51BF-1 51BF-2
87T
A W Var
A W Var 51P
UR Relay
5 SETTINGS
PROD-
GE Multilin