Issue February 2002
Document Number: 13124
- 5 -
2. General
2.1.
ESTAmat PFC
Controller– Application and Operation
The
ESTAmat PFC
Controller
can be applied wherever automatic control of the power factor is
required. All functions of the
ESTAmat PFC
are controlled by a microprocessor. A protective gear
(watchdog) continously monitors the processor to guarantee its faultless operation. There are no
internal time or date functions.
The measurable variables current and voltage are conducted across a 50/60Hz band-pass filter.Thus
harmonics existing in the network cannot affect the measurement process. Both measurement entries
are potential-free. The measuring voltage shall be in the range of 58V-690V and may be connected, at
option, between phase to neutral or phase to phase. The current measuring range is 25mA to 5A, and
there is no need to differentiate between X/1A or X/5A current transformer.
A measuring cycle lasts 0.5 seconds and comprises the measurement of values, the calculation of all
required parameters, such as power factor, current, harmonic current, etc., and if necessary, the
initialization of certain actions, e.g. switching the steps, activating alarm, etc.
2.2. Automatic identification of C.T. location and of capacitor step output
The
ESTAmat PFC
Controller
is capable of determining by itself , during the start-up procedure, the
location of the current transformer as well as the output rating of the connected capacitor steps by
means of test switchings.
Three modes of initialization are possible:
•
Fully automatic initialization
AU1
The
ESTAmat PFC
Controller
identifies the location of the current transformer, the output
and number of capacitor steps, and the switching program.
•
Semi-automatic initialization
AU2
The
ESTAmat PFC
Controller
identifies, upon presetting of the C.T. location, the output and
number of capacitor steps, and the switching program.
•
Manual initialization
AU3
The C.T. location, output and number of capacitor steps, and the switching program have to be
set by the operator.
2.3. C/k value
The C/k-value is the pick-up value of the
ESTAmat PFC
Controller
. The value represents the
reactive current response threshold of the Controller in Ar (ampere reactive). In case the reactive
current portion of the load exceeds the set C/k value, one of the two LEDs "
ind
" or "
cap
" will indicate
the trend. The calculation of the C/k value is described under item 6.3.5.
2.4. Switching in circular sequence
Switching in circular sequence means that capacitors which have been switched in first, will also be
switched out again first. Switching follows the FIFO principle: First-IN-First-OUT. If the switching-in
follows the order 1-2-3-4-5, then also the switching-out of the capacitors will follow that same order .
1-2-3-4-5.
