GE G60 Instruction Manual page 262

5.8 TRANSDUCER I/O
The nominal three-phase power is:
The three-phase power with 20% overload margin is:
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 MIN VALL
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
5
For example at the reading of 20 MW, the worst-case error is 0.01 × 20 MW + 0.207 MW = 0.407 MW.
EXAMPLE 2:
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.
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 MIN 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 3:
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.
5-180
× ×
P 3 13.8 kV 0.8 kA
=
×
P 1.2 17.21 MW
=
max
× ×
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, maximum current
----------- -
= =
5 kA
: "SRC 1 Ia RMS"
: "4 to 20 mA"
: "0.000 pu"
: "1.260 pu"
G60 Generator Management Relay
×
0.9 17.21 MW
=
20.65 MW
=
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
1.26 pu
---------------- -
= =
5 kA
± × ( ) 6.3 kA ×
0.005 20 4
– =
5 SETTINGS
(EQ 5.45)
(EQ 5.46)
(EQ 5.47)
1.247 pu
(EQ 5.48)
=
±
0.207 MW
=
(EQ 5.49)
(EQ 5.50)
(EQ 5.51)
±
0.504 kA
GE Multilin