GE N60 - Page 331

GE Multilin N60 Network Stability and Synchrophasor Measurement System 5-213
5 SETTINGS 5.7 CONTROL ELEMENTS
5
The following table illustrates this application for four sample power values.
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: .
• UR base unit for current: (see FlexElements section for further details).
• Minimum current to be monitored (pu):
The following settings should be applied:
DIGITIZER 1 SOURCE: “SRC 1 Ia RMS” and DIGITIZER 1 LIMIT: “1.260 pu”
Using the above 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 should be configured as follows:
DNA- 14 OPERAND: “DIGITIZER 1 BIT 0” DNA- 18 OPERAND: “DIGITIZER 1 BIT 4”
DNA- 15 OPERAND: “DIGITIZER 1 BIT 1” DNA- 19 OPERAND: “DIGITIZER 1 BIT 5”
DNA- 16 OPERAND: “DIGITIZER 1 BIT 2” DNA- 20 OPERAND: “DIGITIZER 1 BIT 6”
DNA- 17 OPERAND: “DIGITIZER 1 BIT 3”
As the input signal (true RMS) is always positive, the sign bit could be ignored and only seven points need to be
exchanged. On the receiving location, incoming bits 14 through 20 should be configured to drive remote inputs. The latter
together with the FlexLogic constant “Off” for the sign bit should be configured accordingly to use the incoming information
(typically via the 8-bit comparator feature).
The following table illustrates this application for four sample current values.
POWER N
out
B7... B0
15.00 MW 92 01011100
20.00 MW 123 01111011
–5.00 MW –31 10011111
–12.00 MW –74 11001010
CURRENT N
out
B7... B0
1.00 kA 20 00010100
2.50 kA 50 00110010
4.20 kA 85 01010101
6.00 kA 121 01111001
I
max
1.5 4.2 kA 6.3 kA==
I
BASE
5 kA=
6.3 kA 5 kA 1.26= pu