GE L60 Instruction Manual page 313

5 SETTINGS
examples). The setting is entered in per-unit values. The base units are defined in the same manner as the FlexEle-
ment™ base units.
The
DCMA OUTPUT H1 MIN VAL
the
DCMA OUTPUT H1 SOURCE
NOTE
Three application examples are described below.
EXAMPLE 1:
A three phase active power on a 13.8 kV system measured via UR-series relay source 1 is to be monitored by the dcmA H1
output of the range of –1 to 1 mA. The following settings are applied on the relay: CT ratio = 1200:5, VT secondary 115, VT
connection is delta, and VT ratio = 120. 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 compared to the nominal.
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
: "–1 to 1 mA"
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 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:
GE Multilin
and
DCMA OUTPUT H1 MAX VAL
is set to FlexAnalog value based on power factor measurement).
× ×
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"
: "–1.247 pu"
: "1.247 pu"
×
I 1.5 4.2 kA
=
max
I
=
BASE
0 kA
----------- - 0 pu, maximum current
= =
5 kA
L60 Line Phase Comparison Relay
5.8 TRANSDUCER INPUTS/OUTPUTS
settings are ignored for power factor base units (i.e. if
×
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
(EQ 5.23)
(EQ 5.24)
(EQ 5.25)
1.247 pu
(EQ 5.26)
=
±
0.207 MW
=
(EQ 5.27)
(EQ 5.28)
(EQ 5.29)
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