8
2. Functions
The reactive power and active power por-
tions of the power source are continuously
calculated in the control relay from the
measured voltage and the signals of the
current transformer. If the reactive power
portion exceeds certain threshold values,
which the control relay has measured at
the time of auto-adaption or are set as per
section 5, a switching action will take
place at the switching outputs.
In the case of inductive reactive current
(inductive reactive power) one or more
control contacts of the reactive power con-
trol relay are closed after the prepro-
grammed time delay.
This causes the RM 9606 to switch ca-
pacitor stages onto the power source sup-
ply, as and when required, in order to
achieve the programmed target power
factor. If the inductive reactive current por-
tion of the load is reduced, the excess of
reactive current causes the capacitor
stages to be switched off line.
The Control Relay RM 9606 allows a
variety of possible settings to meet the
conditions on site. The relay's cyclic op-
erations prolong the life of all connected
devices by averaging the length of time
the capacitor stages are switched on. An
effective supervision of the reactive power
control system (capacitor bank) is secured
by the power factor display.
2.1 Automatic Identification of
Voltage and Current Source
When voltage is initially applied to the con-
trol relay, it determines the location of the
current and voltage sources (automatic
phase rotation), i.e. it identifies in which
phase and at which phase angle the cur-
rent path and the voltage path are con-
nected. Should the control relay fail to
identify the current and voltage source due
to power instabilities, repeat the procedure
when the power has stabilized. It is also
possible to programme the phasing
manually (see sections 5.10 and 5.11).
Resetting of the control relay and re-
identification of voltage and current
sources is initiated by pressing but-
tons "+" and "Set" simultaneously for
at least 8 seconds.
2.2 Automatic Identification of the
Connected Capacitor Stages
Having determined the voltage and current
source identification, the RM 9606 auto-
matically calculates the c/k identification.
During the identification process all the
control contacts of the relay are individu-
ally switched on and off again. The stage
currents ascertained are then stored.
These values determine the stage se-
quence. In this way it can also be deter-
mined which switching outputs are in use.
