GE L90 Instruction Manual page 298

5.8 TRANSDUCER I/O
The relay checks the driving signal (x in equations below) for the minimum and maximum limits, and subsequently re-
scales so the limits defined as
ing equation is applied:
where: x is a driving signal specified by the
I and I
min max
k is a scaling constant calculated as:
The feature is intentionally inhibited if the
< 0.1 pu. The resulting characteristic is illustrated in the following figure.
VAL
5
The dcmA output settings are described below.
• DCMA OUTPUT H1 SOURCE: This setting specifies an internal analog value to drive the analog output. Actual values
(FlexAnalog parameters) such as power, current amplitude, voltage amplitude, power factor, etc. can be configured as
sources driving dcmA outputs. Refer to Appendix A for a complete list of FlexAnalog parameters.
• DCMA OUTPUT H1 RANGE: This setting allows selection of the output range. Each dcmA channel may be set inde-
pendently to work with different ranges. The three most commonly used output ranges are available.
• DCMA OUTPUT H1 MIN VAL: This setting allows setting the minimum limit for the signal that drives the output. This
setting is used to control the mapping between an internal analog value and the output current (see the following
examples). The setting is entered in per-unit values. The base units are defined in the same manner as the FlexEle-
ment™ base units.
• DCMA OUTPUT H1 MAX VAL: This setting allows setting the maximum limit for the signal that drives the output. This
setting is used to control the mapping between an internal analog value and the output current (see the following
examples). The setting is entered in per-unit values. The base units are defined in the same manner as the FlexEle-
ment™ base units.
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.
5-208
and
MIN VAL MAX VAL
I if x

min

I if x
I

=
max
out

(
k x
 MIN VAL
–
SOURCE
are defined by the setting
RANGE
k ------------------------------------------------ -
=
MAX VAL
MAX VAL
I
max
I
min
MIN VAL
Figure 5–117: DCMA OUTPUT CHARACTERISTIC
L90 Line Differential Relay
match the output range of the hardware defined as
<
MIN VAL
>
MAX VAL
)
I otherwise
+
min
setting
I I
–
max min
MIN VAL
–
and settings are entered incorrectly, e.g. when
MIN VAL
DRIVING SIGNAL
MAX VAL
5 SETTINGS
. The follow-
RANGE
MAX VAL
842739A1.CDR
(EQ 5.22)
(EQ 5.23)
–
MIN
GE Multilin