NHP Terasaki TemBreak PRO P SE Series, Руководство пользователя

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Measurements and settings
Power Related Measurements
58
TemBreak PRO
P_SE-UM-001-EN
– V1.2.0
Reactive and apparent power calculation convention
Total reactive (Q
tot
) and apparent (S
tot
) power for a 3-phase-3-wire system are calculated in the P_SE OCR using either Arithmetic or Vector convention,
which is selectable during configuration.
Changes to the reactive and apparent power calculation convention can be made using one or a combination of the below methods:
-
TPED
-
TPCM
TPED setting TPCM setting Default
“Calc. convention”
Arithmetic: Arithmetic convention
Vector:
Vector convention
Command ID: 104 “ Calculation formula for Reactive and Apparent power ”
Hex 00 00: Arithmetic convention
Hex 00 01: Vector convention
Vector convention
The selection of either convention depends on user or application preference, however, does impact the calculation of other power related measurements
which utilize total reactive (Q
tot
) and apparent (S
tot
) power. Differences between the results of the calculation convention used are more prominent in
unbalanced 3-phase systems.
Arithmetic convention: Total apparent power (S
totA
) is calculated by adding the absolute magnitude of the apparent power (|S
p
|) of each phase.
S
totA
=
|
S
1
|
+
|
S
2
|
+
|
S
3
|
Therefore, total reactive power (Q
totA
) is calculated by using the known total real power (P
tot
) and the arithmetic S
totA
.
Q
totA
= ± √ S
totA
2
- P
tot
2
Vector convention: Total apparent power (S
totV
) is calculated by adding the known total real power (P
tot
) and total reactive power (Q
totV
).
S
totV
= √ P
tot
2
+Q
totV
2
The calculation of total reactive power (Q
totV
) is performed by adding the vector sum of the apparent power for each phase
(Q
p
).
Q
totA
= Q
1
+ Q
2
+ Q
3
Values which are affected by calculation convention setting are as follows:
Variables Symbols
Total reactive and apparent power Q
tot
, S
tot
Average reactive and apparent power over interval (Demand power) Q
tot Dmd
, S
tot Dmd
Maximum Average reactive and apparent power over interval (Demand
power) since the last reset
Max. of each Q
tot Dmd
, S
tot Dmd
Reactive energy produced, consumed, absolute and signed totals E
r In
, E
r Out
, E
r Abs
, E
r
Apparent energy E
s
Power factor PF
1
, PF
2
, PF
3
, PF
tot
Total displacement power factor Cos
ϕ
tot