GE L90 Instruction Manual page 100

5.2 PRODUCT SETUP
The
CURRENT CUT-OFF LEVEL
power cut-off level is calculated as follows:
power cut-off level
For example, given the following settings:
CURRENT CUT-OFF LEVEL
VOLTAGE CUT-OFF LEVEL
PHASE CT PRIMARY
PHASE VT SECONDARY
: "208.00 : 1".
PHASE VT RATIO
We have:
1.0 pu current = CT primary = "100 A", and
1.0 pu voltage =
PHASE VT SECONDARY
The power cut-off is therefore:
power cut-off =
CURRENT CUT-OFF LEVEL
= 0.02 pu × 0.015 pu × 100 A × 13811.2 V
= 416 watts
Any calculated power value below this cut-off will not be displayed. As well, the three-phase energy data will not accumu-
late if the total power from all three phases does not exceed the power cut-off.
Lower the
VOLTAGE CUT-OFF LEVEL
as valid measurements. Unless dictated otherwise by a specific application, the default settings of "0.02
pu" for
NOTE
CURRENT CUT-OFF LEVEL
5
5-10
and the
VOLTAGE CUT-OFF LEVEL
×
CURRENT CUT-OFF LEVEL
=
: "0.02 pu"
: "1.0 V"
: "100 A"
: "66.4 V"
x
PHASE VT RATIO
×
VOLTAGE CUT-OFF LEVEL
and
CURRENT CUT-OFF LEVEL
and "1.0 V" for
L90 Line Differential Relay
are used to determine the metered power cut-off levels. The
×
1.0 pu current
VOLTAGE CUT-OFF LEVEL
= 66.4 V x 208 = 13811.2 V
× 1.0 pu current × 1.0 pu voltage
with care as the relay accepts lower signals
VOLTAGE CUT-OFF LEVEL
5 SETTINGS
×
1.0 pu voltage
are recommended.
(EQ 5.3)
GE Multilin