EQUATION1981-ANSI V1 EN (Equation 426)
Thereafter the current I
C
at the actual measured voltage VB can be calculated as:
EQUATION1982-ANSI V1 EN (Equation 427)
In this way the measured LV currents can be adjusted so that the capacitor bank current
will not influence the calculation of the circulating current.
Three independent capacitor bank values Q1, Q2 and Q3 can be set for each
transformer in order to make possible switching of three steps in a capacitor bank in
one bay.
Power monitoring
The level (with sign) of active and reactive power flow through the transformer, can be
monitored. This function can be utilized for different purposes for example, to block
the voltage control function when active power is flowing from the LV side to the HV
side or to initiate switching of reactive power compensation plant, and so on.
There are four setting parameters P>, P<, Q> and Q< with associated outputs in
TR8ATCC (90) and TR1ATCC (90) function blocks PGTFWD, PLTREV, QGTFWD
and QLTREV. When passing the pre-set value, the associated output will be activated
after the common time delay setting tPower.
The definition of direction of the power is such that the active power P is forward when
power flows from the HV-side to the LV-side as shown in figure
285. The reactive
power Q is forward when the total load on the LV side is inductive ( reactance) as
shown in figure 285.
Section 3 1MRK504116-UUS C
IED application
672
Application manual
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