5-154
N60 Network Stability and Synchrophasor Measurement System
GE Multilin
5.6 CONTROL ELEMENTS
5 SETTINGS
5
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
ÖØ
METERING
ÖØ
DIGITIZERS
values for details).
•
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).
Figure 5–73: DIGITIZER LOGIC
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:
DIGITIZER 1 SOURCE:
“SRC 1 P" and
DIGITIZER 1 LIMIT:
“2.160 pu”.
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:
“
DIGITIZER 1 BIT 0
”
DIRECT OUT 24 OPERAND:
“
DIGITIZER 1 BIT 4
”
DIRECT OUT 21 OPERAND:
“
DIGITIZER 1 BIT 1
”
DIRECT OUT 25 OPERAND:
“
DIGITIZER 1 BIT 5
”
DIRECT OUT 22 OPERAND:
“
DIGITIZER 1 BIT 2
”
DIRECT OUT 26 OPERAND:
“
DIGITIZER 1 BIT 6
”
DIRECT OUT 23 OPERAND:
“
DIGITIZER 1 BIT 3
”
DIRECT OUT 27 OPERAND:
“
DIGITIZER 1 BIT 7
”
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).
842015A2.CDR
DIGITIZER 1 LIMIT:
DIGITIZER 1 SOURCE:
SETTING
SETTINGS
FLEXLOGIC OPERANDS
ACTUAL VALUE
Off=0
DIGITIZER 1 BIT 0
LSB
DIGITIZER 1 BIT 2
DIGITIZER 1 BIT 4
DIGITIZER 1 BIT 6
MSB
DIGITIZER 1 Out
DIGITIZER 1 BIT 1
DIGITIZER 1 BIT 3
DIGITIZER 1 BIT 5
DIGITIZER 1 BIT 7
SIGN
DIGITIZER 1 FUNCTION:
RUN
SETTING
Disabled=0
Enabled=1
P
3
13.8 kV
0.8 kA
×
0.9
×
×
17.21 MW
=
=
P
max
1.2
17.21 MW
×
20.65 MW
=
=
P
BASE
VT ratio
VT secondary
CT primary
×
×
120
66.4 V
1.2 kA
×
×
9.56 MW
=
=
=
20.65 MW 9.56 MW
⁄
2.160 pu
=