ABB RET650 Applications Manual page 238

Section 11
Control
232
en06000635_2_en.vsd
IEC06000635 V2 EN-US
Figure 85: Setting of a positive value for P<
Q>: When the reactive power exceeds the value given by this setting, the output
QGTFWD will be activated after the time delay tPower. It shall be noticed that the
setting is given with sign, which effectively means that the function picks up for all
values of reactive power greater than the set value, similar to the functionality for
P>.
Q<: When the reactive power falls below the value given by this setting, the output
QLTREV will be activated after the time delay tPower. It shall be noticed that the
setting is given with sign, which effectively means that the function picks up for all
values of reactive power less than the set value, similar to the functionality for P<.
tPower: Time delay for activation of the power monitoring output signals
(PGTFWD, PLTREV, QGTFWD and QLTREV).
Parallel control (ParCtrl)
OperationPAR: Setting of the method for parallel operation.
OperCCBlock: This setting enables/disables blocking if the circulating current
exceeds CircCurrLimit.
CircCurrLimit: Pick up value for the circulating current blocking function. The
setting is made in percent of I2Base.
tCircCurr: Time delay for the circulating current blocking function.
Comp: When parallel operation with the circulating current method is used, this
setting increases or decreases the influence of the circulating current on the
regulation.
If the transformers are connected to the same bus on the HV- as well as the LV-
side, Comp can be calculated with the following formula which is valid for any
number of two-winding transformers in parallel, irrespective if the transformers are
of different size and short circuit impedance.
´ D
2 U
= ´ ´
Comp a 100%
´
n p
EQUATION1941 V1 EN-US
where:
P
P<
1MRK 504 169-UEN A
(Equation 57)
Transformer protection RET650 2.2 IEC
Application manual