Basler Electric BE1-11t - Manual (Page 298)

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BESTCOMSPlus Navigation Path: Settings Explorer, System Parameters, Sensing Transformers
HMI Navigation Path: Settings Explorer, System Parameters, Sensing Transformers
CT Setup
The BE1-11t 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)
𝐼
𝑈𝑛𝑏𝑎𝑙𝑎𝑛𝑐𝑒
=
𝐼
2
𝐼
1
× MIN
where:
MIN =
𝐼
𝐴𝑣𝑒𝑟𝑎𝑔𝑒
𝐼
𝑅𝑎𝑡𝑒𝑑
or 1, whichever is less
Method 2 (Average)
𝐼
𝑈𝑛𝑏𝑎𝑙𝑎𝑛𝑐𝑒
=
�MAXp − I
𝐴𝑣𝑒𝑟𝑎𝑔𝑒
� or �I
𝐴𝑣𝑒𝑟𝑎𝑔𝑒
− MINp�, whichever is greater
I
𝐴𝑣𝑒𝑟𝑎𝑔𝑒
× MIN
where:
MIN =
𝐼
𝐴𝑣𝑒𝑟𝑎𝑔𝑒
𝐼
𝑅𝑎𝑡𝑒𝑑
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 BE1-11t 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. 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 for directional overcurrent protection (67).
Settings
Sensing transformers settings are configured on the Sensing Transformers settings screen (Figure 230)
in BESTCOMSPlus. Setting ranges and defaults are summarized in Table 93.
Configuration BE1-11t