GE Multilin g60 Instruction Manual page 434

5.9 TRANSDUCER INPUTS AND OUTPUTS
The base unit for power (refer to the FlexElements section in this chapter for additional details) is:
The minimum and maximum power values to be monitored (in pu) are:
minimum power
The following settings should be entered:
DCMA OUTPUT H1 SOURCE
DCMA OUTPUT H1 RANGE
DCMA OUTPUT H1 MIN VAL
DCMA OUTPUT H1 MAX VAL
With the above settings, the output will represent the power with the scale of 1 mA per 20.65 MW. The worst-case error for
this application can be calculated by superimposing the following two sources of error:
• ±0.5% of the full scale for the analog output module, or
• ±1% of reading error for the active power at power factor of 0.9
For example at the reading of 20 MW, the worst-case error is 0.01  20 MW + 0.207 MW = 0.407 MW.
EXAMPLE: CURRENT MONITORING
The phase A current (true RMS value) is to be monitored via the H2 current output working with the range from 4 to 20 mA.
The CT ratio is 5000:5 and the maximum load current is 4200 A. The current should be monitored from 0 A upwards, allow-
ing for 50% overload.
5
The phase current with the 50% overload margin is:
The base unit for current (refer to the FlexElements section in this chapter for additional details) is:
The minimum and maximum power values to be monitored (in pu) are:
minimum current
The following settings should be entered:
DCMA OUTPUT H2 SOURCE
DCMA OUTPUT H2 RANGE
DCMA OUTPUT H2 MIN VAL
DCMA OUTPUT H2 MAX VAL
The worst-case error for this application could be calculated by superimposing the following two sources of error:
• ±0.5% of the full scale for the analog output module, or
• ±0.25% of reading or ±0.1% of rated (whichever is greater) for currents between 0.1 and 2.0 of nominal
For example, at the reading of 4.2 kA, the worst-case error is max(0.0025  4.2 kA, 0.001  5 kA) + 0.504 kA = 0.515 kA.
EXAMPLE: VOLTAGE MONITORING
A positive-sequence voltage on a 400 kV system measured via source 2 is to be monitored by the dcmA H3 output with a
range of 0 to 1 mA. The VT secondary setting is 66.4 V, the VT ratio setting is 6024, and the VT connection setting is
"Delta". The voltage should be monitored in the range from 70% to 110% of nominal.
The minimum and maximum positive-sequence voltages to be monitored are:
V
min
The base unit for voltage (refer to the FlexElements section in this chapter for additional details) is:
5-274

P 115 V 120
=
BASE
20.65 MW
–
------------------------------ 1.247 pu,
= = –
16.56 MW
: "SRC 1 P"
: "–1 to 1 mA"
: "–1.247 pu"
: "1.247 pu"

I 1.5 4.2 kA
=
max
I
BASE
0 kA
----------- - 0 pu,
= =
5 kA
: "SRC 1 Ia RMS"
: "4 to 20 mA"
: "0.000 pu"
: "1.260 pu"
400 kV

------------------ -
0.7 161.66 kV,
= =
3
G60 Generator Protection System

1.2 kA 16.56 MW
=
20.65 MW
maximum power -------------------------- -
=
16.56 MW
   –    
0.005 1 1 20.65 MW
–
6.3 kA
=
5 kA
=
6.3 kA
maximum current ---------------- -
= =
5 kA
    6.3 kA 
0.005 20 4
–
400 kV

------------------ -
V 1.1 254.03 kV
= =
max
3
5 SETTINGS
(EQ 5.57)
1.247 pu
(EQ 5.58)
=

0.207 MW
=
(EQ 5.59)
(EQ 5.60)
1.26 pu
(EQ 5.61)

0.504 kA
=
(EQ 5.62)
GE Multilin