8-Bit Comparators - GE N60 Instruction Manual

CHAPTER 5: SETTINGS
Application example 2
The phase A current (true RMS value) is to be sent via remote outputs (MMS GOOSE) to several remote IEDs (DNA points 14
through 20). The CT ratio is 5000:5 and the maximum load current is 4200 A. The current should be monitored allowing for
50% overload.
• Phase current with the 50% overload margin: I
• UR base unit for current: I
• Minimum current to be monitored (pu): 6.3 kA/5 kA = 1.26 pu
The following settings are applied:
Using these settings, the output represents current magnitude with the scale of 127 per 6.3 kA; for example, one count of a
digitizer output represents 6.3 kA / 127 = 49.6 A.
The remote outputs are configured as follows:
: "DIGITIZER 1 BIT 0"
DNA- 14 OPERAND
: "DIGITIZER 1 BIT 4"
DNA- 18 OPERAND
: "DIGITIZER 1 BIT 1"
DNA- 15 OPERAND
: "DIGITIZER 1 BIT 5"
DNA- 19 OPERAND
: "DIGITIZER 1 BIT 2"
DNA- 16 OPERAND
: "DIGITIZER 1 BIT 6"
DNA- 20 OPERAND
: "DIGITIZER 1 BIT 3"
DNA- 17 OPERAND
As the input signal (true RMS) is always positive, the sign bit can be ignored and only seven points need to be exchanged.
On the receiving location, incoming bits 14 through 20 are configured to drive remote inputs. The latter together with the
FlexLogic constant "Off" for the sign bit is configured accordingly to use the incoming information (typically via the eight-
bit comparator feature).
The table illustrates this application for four sample current values.
Table 5-42: Sample current values
Current N
out
1.00 kA 20
2.50 kA 50
4.20 kA 85
6.00 kA 121

5.8.13 8-bit comparators

SETTINGS  CONTROL ELEMENTS  8-BIT COMPARATORS  8-BIT COMPARATOR 1(6)
 8-BIT
 COMPARATOR 1
N60 NETWORK STABILITY AND SYNCHROPHASOR MEASUREMENT SYSTEM – INSTRUCTION MANUAL
= 1.5 x 4.2 kA = 6.3 kA
max
= 5 kA (see FlexElements section for further details)
BASE
= "SRC 1 Ia RMS" and
DIGITIZER 1 SOURCE
B7... B0
00010100
00110010
01010101
01111001
8BIT COMP 1

FUNCTION: Disabled
8BIT COMP 1 ARG A0:

Off
8BIT COMP 1 ARG A1:

Off

8BIT COMP 1 ARG A7:

Off
8BIT COMP 1 ARG B0:

Off
8BIT COMP 1 ARG B1:

Off

= "1.260 pu"
DIGITIZER 1 LIMIT
Range: Disabled, Enabled
Range: FlexLogic operand
Range: FlexLogic operand
Range: FlexLogic operand
Range: FlexLogic operand
Range: FlexLogic operand
CONTROL ELEMENTS
5
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