GE N60 Instruction Manual page 330

5.7 CONTROL ELEMENTS
For critical applications, users should ensure the validity of the digitizer input signal to prevent an undesired response of the
relaying system. For example, configuring the VT fuse failure condition when the digitizer uses the voltage signal.
The digitized output value is available as an actual value for testing, troubleshooting and special applications (refer to the

ACTUAL VALUES METERING
• DIGITIZER 1 SOURCE: This setting specifies an internal analog value to be digitized. A variety of analog actual values
(FlexAnalog parameters) such as power, current amplitude, voltage amplitude, power factor, etc., can be configured as
the digitizer source. Refer to Appendix A for a complete list of FlexAnalog parameters available for the N60.
• DIGITIZER 1 LIMIT: This setting allows setting symmetrical limits for the input signal. The input signal is truncated to
an interval from –LIMIT to +LIMIT before the effective digitization. The base units are defined in the exact manner as
FlexElements™ (see the FlexElements™ section for details).
5
APPLICATION EXAMPLE 1:
A three phase active power on a 13.8kV system measured via UR source 1 is to be sent via Direct Outputs, bits 20 through
27, to a remote location. The following settings are applied on the relay: CT ratio = 1200:5, VT ratio = 120, and VT second-
ary = 66.4 V. The nominal current is 800 A primary and the nominal power factor is 0.90. The power is to be monitored in
both importing and exporting directions and allow for 20% overload as compared with the nominal.
• Nominal three-phase power:
• Three-phase power with the 20% overload margin:
• UR base unit for power:
(see the FlexElements section for further details).
• Maximum power to be monitored (pu):
The following settings should be applied:
Using the above settings, the output represents power with the scale of 127 per 20.65 MW; for example, 1 count of a digi-
tizer output represent 20.65 MW / 127 = 162.6 kW.
The direct outputs should be configured as follows:
DIRECT OUT 20 OPERAND:
DIRECT OUT 21 OPERAND:
DIRECT OUT 22 OPERAND:
DIRECT OUT 23 OPERAND:
On the receiving location, bits 20 through 27 should be configured to drive eight direct inputs. The latter should be config-
ured accordingly to use the incoming information (typically via the 8-bit comparator feature).
5-212
 values for details).
DIGITIZERS
Figure 5–89: DIGITIZER LOGIC
 
P 3 13.8 kV 0.8 kA
=
P

P VT ratio VT secondary CT primary
=
BASE

20.65 MW 9.56 MW
DIGITIZER 1 SOURCE:
" "
DIGITIZER 1 BIT 0
DIRECT OUT 24 OPERAND:
" "
DIGITIZER 1 BIT 1
DIRECT OUT 25 OPERAND:
" "
DIGITIZER 1 BIT 2
DIRECT OUT 26 OPERAND:
" "
DIGITIZER 1 BIT 3 DIRECT OUT 27 OPERAND:
N60 Network Stability and Synchrophasor Measurement System

0.9 17.21 MW .
=

1.2 17.21 MW 20.65 MW
= =
max
 
120 66.4 V 1.2 kA
=
2.160 pu .
=
"SRC 1 P" and
DIGITIZER 1 LIMIT:
"
DIGITIZER 1 BIT 4
"
DIGITIZER 1 BIT 5
"
DIGITIZER 1 BIT 6
"
DIGITIZER 1 BIT 7
5 SETTINGS
.

9.56 MW
=
"2.160 pu".
"
"
"
"
GE Multilin