Basler Electric BE1-11t - Manual (Page 295)

9424200995 Rev H 283
C B A 3
Vars Vars Vars Vars
+ + =
φ
where:
X PN P
I V
∠ − ∠ = φ
For Sensing Type: Three-wire
In three-wire sensing mode, the equivalent LN voltages are determined from the LL voltages assuming
3V
0
= 0V. This allows per-phase watts and vars to be determined and provides improved accuracy over a
two-element method when neutral current is present.
) V
ˆ
V
ˆ
( 3 / 1 V
ˆ
CA AB AN
− ⋅ =
) V
ˆ
V
ˆ
( 3 / 1 V
ˆ
AB BC BN
− ⋅ =
) V
ˆ
V
ˆ
( 3 / 1 V
ˆ
BC CA CN
− ⋅ =
Using the computed PN voltages, watts and vars are then computed using the equations listed under
four-wire sensing type, above.
For Single Phase Sensing Types: AN, BN, CN, AB, BC, CA
In single-phase sensing mode, the unknown PN voltages are calculated. Assuming a balanced three-
phase voltage is applied, the unknown PN voltages can be determined by scaling and rotating the
measured voltage as follows:
ABC Rotation
AN Sensing: ° − ∠ ⋅ =
120 1 V V
AN BN
° ∠ ⋅ =
120 1 V V
AN CN
BN Sensing: ° ∠ ⋅ =
120 1 V V
BN AN
° − ∠ ⋅ =
120 1 V V
BN CN
CN Sensing: ° − ∠ ⋅ =
120 1 V V
CN AN
° ∠ ⋅ =
120 1 V V
CN BN
AB Sensing: ° − ∠ ⋅ =
30 1 V V
AB AN
3
1
° − ∠ ⋅ =
150 1 V V
AB BN
3
1
° ∠ ⋅ =
90 1 V V
AB CN
3
1
BC Sensing: ° ∠ ⋅ =
90 1 V V
AB AN
3
1
° − ∠ ⋅ =
30 1 V V
AB BN
3
1
° − ∠ ⋅ =
150 1 V V
AB CN
3
1
CA Sensing: ° − ∠ ⋅ =
150 1 V V
AB AN
3
1
° ∠ ⋅ =
90 1 V V
AB BN
3
1
° − ∠ ⋅ =
30 1 V V
AB CN
3
1
ACB Rotation
AN Sensing: ° ∠ ⋅ =
120 1 V V
AN BN
° − ∠ ⋅ =
120 1 V V
AN CN
BN Sensing: ° − ∠ ⋅ =
120 1 V V
BN AN
° ∠ ⋅ =
120 1 V V
BN CN
CN Sensing: ° ∠ ⋅ =
120 1 V V
CN AN
° − ∠ ⋅ =
120 1 V V
CN BN
AB Sensing: ° ∠ ⋅ =
30 1 V V
AB AN
3
1
° ∠ ⋅ =
150 1 V V
AB BN
3
1
° − ∠ ⋅ =
90 1 V V
AB CN
3
1
BC Sensing: ° − ∠ ⋅ =
90 1 V V
AB AN
3
1
° ∠ ⋅ =
30 1 V V
AB BN
3
1
° ∠ ⋅ =
150 1 V V
AB CN
3
1
CA Sensing: ° ∠ ⋅ =
150 1 V V
AB AN
3
1
° − ∠ ⋅ =
90 1 V V
AB BN
3
1
° ∠ ⋅ =
30 1 V V
AB CN
3
1
Using both the measured and calculated PN voltages, watts and vars are then computed using the
equations listed under four-wire sensing type above.
BE1-11t Configuration