348 9424200994 Rev N
BESTCOMSPlus Navigation Path: Settings Explorer, System Parameters, Sensing Transformers
HMI Navigation Path: Settings Explorer, System Parameters, Sensing Transformers
CT Setup
The BE1-11g requires setting information on the CT ratios. This setting is used by the metering and fault
reporting functions to display measured quantities in primary units.
Unbalanced Calculation Method
Unbalanced overcurrent protection is provided by the 50 and 51 elements. Two methods are available to
calculate unbalanced current.
Method 1 (I2/I1)
=
× MIN
where:
MIN =
or 1, whichever is less
Method 2 (Average)
=
MAXp I
or I
MINp, whichever is greater
I
× MIN
where:
MIN =
or 1, whichever is less
MAXp = maximum of all three phases
MINp = minimum of all three phases
Connection
This setting defines how the sensing CTs are connected for differential metering.
Phase VT Setup
The BE1-11g requires setting information about the VT ratio, the phase connections, and the operating
modes for the 27/59 and 27R functions. These settings are used by the metering and fault reporting
functions to display measured quantities in primary units. The voltage input circuit settings also determine
which power measurement calculations are used. Most of these connections such as 3W-D, 4W-Y, AN, or
AB are self-explanatory.
Auxiliary VT Setup
The auxiliary voltage input (Vx) connection can be set for AB, BC, CA, AN, BN, CN, or Ground. When set
for one of the phase voltages, the sync-check function can be set to compensate for the phase angle
difference relative to the reference voltage measured at the three-phase voltage inputs. The Vx input
connection is set to Ground when connected to a source of ground unbalance voltage or residual voltage
such as a generator grounding resistor, broken delta VT connection, or capacitor bank star point.
Bus CT Selection
The CT Source setting selects the set of CTs to use in calculations for power protection (32, 40Q) and
impedance protection (21, 40Z, 78OOS) on protection systems equipped with two sets of CTs. The CT
Source setting also selects the set of CTs to use for directional overcurrent protection (67).
Configuration BE1-11g
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