Upload
greendot-india
View
62
Download
0
Embed Size (px)
Citation preview
Green Dot AUTOMATIC
POWER FACTOR
CONTROLLER
AN IDEAL SOLUTION for POWER FACTOR
CORRECTION
FIRST TIME IN INDIA
This is 3rd Generation of Development in the APFC Field.
The Market – till today was exposed to
the SECOND GENERATION units that are RELAY TYPE akin to RELAY TYPE
STABILISERS in Voltage stabiliser field. This is SERVO TYPE APFC CONTROLLER –
CONTINUOUSLY CORRECTING TYPE.
This will upgrade your concept of POWER FACTOR CORRECTION.
THE UNBALANCED TYPE APFC provides IDEAL CORRECTION to INDIVIDUAL
PHASES . This objective & advantage is not
possible from RELAY TYPE Power Factor Panels.
AT EXISTING INSTALLATIONS of RELAY
TYPE POWER FACTOR PANEL installations – a SMALL SIZED UNBALANCED TYPE UNIT will further correct POWER FACTOR of INDIVIDUAL PHASES by correcting PF of
INDIVIDUAL PHASES from AVERAGE FIGURES of SAY 0.95-0.97 to 1 & thus further saving 3-4 % on Electricity Bills.
SAY ADD 10 KVAR or 20 KVAR CONSTANTLY VARIABLE CAPACITORS in INDIVIDUAL
PHASES.
An INNOVATIVE PRODUCT
The innovative character of this APFC
controller can be best understood from
the anomaly with the Voltage stabiliser
field.
There are three STAGES of development
in the field of VOLTAGE STABILISERS /
VOLTAGE REGULATORS. The latest is a
SERVO TYPE VOLTAGE STABILISER. –
that maintains Voltage of any
establishment to + 1 % or so accuracies.
Earlier – 1st Stage was when – a Voltage
Regulator of MANUAL ROTARY TYPE was
used to adjust the voltage as is still being
done on Voltage regulators for TV etc.
There is ONE b4,6 or 8 POSITION rotary
switch that is rotated to adjust output
voltage.
In 2nd stage of this development, RELAY
TYPE STABILISERS like those used with
Air Conditioners etc. came in. There are
Steps ( 2,3,4 or 5 ) – and we call them in
the Regulating Transformers that are
Switched ON and OFF to keep output
voltage to say + 10 % or so accuracy.
In the 3rd Stage – the Servo stabilisers
came in that maintain output voltage
accuracy of + 1 % or so by using a Motor
Driven Variable Transformer .
Similarly in Power Factor Controllers, in the 1st Stage – fixed value capacitors are
added in parallel to individual motors or loads. This is a Crude method of Power
Factor Correction.
In the 2nd Stage – is the conventional Power Factor Controller that incorporates a Set of
Discrete value capacitors that are switched ON & Off to the value required through a set
of Contactors & a POWER FACTOR SENSING RELAY . This operation is similar to the
Voltage Stabilisers of Air Conditioners that contains steps & cannot switch on and off the
capacitors to any definite value required . The switching IN & OUT of the Capacitors is in
steps of say 2 KVR or so.
In the 3rd stage, similar to SERVO STABILISERS – there is no APFC that can Continuously feed
VARIABLE CAPACITANCE in the line. GREEN DOT is only ONE & ONE COMPANY in INDIA
that has perfected the technology of Cotinuously varying capacitance and have thus
introduced STEP LESS POWER FACTOR CONTROLLERS.
Further more , the existing system has some serious disadvantages. You cannot have ideal
compensation to reactive power as because of the steps only a near about compensation to Power
Factor is available. The System will always be over compensated or under compensated. The
degree of compensation deviates undesirably from the ideal values. When using six capacitors –
the deviation could be to 1/12 of the compensate value.
There exists a fear of over improvement and a name is given to this as ‘ power factor
correction better than 0.9’. With combination of increments in sizeable capacitor steps,
and abrupt full current switching, , over improvement could cause over voltages of as much
as 40 % on affected power lines and subsequent damage to motor driven equipment under
certain conditions of operation.
With every capacitive switching of capacitors, a surge or spike like , results, thus causing
a perceivable flicker which is extremely detrimental to sensitive electronic switching
loads connected to line. In fact - the capacitor switching is primary cause of trouble in
computer receiving power from lines. True in the Capacitive switching circuits, today
switching is made at ZERO VOLTAGE CROSSING, but this feature achieves a little
because in capacitors, when voltage curve is at zero , the current curve is at peak and vice
versa.
Even in the absence of Sensitive Electronic loads, the operation of contactors is a rough &
violent physical action – resulting in frequently blowing of fuses . This results in watt
losses & in this interim period, the kilowatt demand increases operational expenses until
those fuses are replaced.
If the load in power lines consists of rectifiers and particularly of rectifiers with forced
communication, which as it is known , it generates a substantial reactive power component,
and also very substantial 5th, 7th and 11th harmonics. With rectifier transformer winding
, a resonant circuit develops whose frequency closely coincides with frequency of said 5th
Harmonic, making the current seriously dangerously uncontrollable.
The capacitors used have to be furnished with discharging resistances. When there is a
power failure, a Power Disconnection or a fuse blowing and – fuses blow frequently – the
circuit has no path of discharge any where , and without discharge resistors, the
capacitors would explode at next energization, when added to existing charge. These
discharge resistances have certain cost and also consume power incessantly.
The capacitors work at all time at full rated voltage and at certain switching instances the
peak voltage is enhanced beyond the rated peak voltage of capacitors – which can destroy
or reduce the life time of these components.
Since the switching of multiple capacitors through contactors is involved, plethora of
harmonics gets introduced in the line & thereby LINE FILTERS of suitable rating have to
be installed. It is like first introducing the NOISES & HARMONICS & then putting
circuits & chokes to mitigate their evil effects.
Green Dot Electric Limited has developed a Variac Based Power Factor Panel. A Motorised
Variable Transformer ( the Motorised Dimmer Dot ) is used a source of Variable Voltage
that is applied to the required value of Capacitance rated for 440 Volts or so. The varying
voltage applied to the Fixed value capacitance-makes the Fixed value Capacitance to
Continuously Variable capacitance that is used to correct the Power Factor without steps.
There are no switching of Contactors or interruption of CAPACITIVE CIRCUITS and thus no
harmonics get introduced. The costly harmonics filters are also avoided. In case the supply
goes off & comes in – delay is provided to give time for discharge of capacitors and then to
start again at zero voltage input from the Dimmer Dot. There is further advantage in our
system that the power change is proportional to the square of applied voltage to the
capacitors whereas by comparison to Switching In, and or out Capacitors – the affect is
only to the first power of the capacitor size.
The Power Factor Sensing relay has been developed from an advanced Micro Controller that
senses the existing Power Factor & rotates the Variable Transformer forward or backward –
increasing or decreasing the output voltage of the Variable transformer, to provide required
voltage across the capacitor so that the adjusted & the required power factor is always
maintained with respect to ever varying load of the establishment. The LED Read out panel
of the Relay Box reads Input Voltage & adjusted Power Factor
THE STEP LESS POWER FACTOR CONTROLLER
Thus there is step less Varying capacitance that is made available to suit the varying
load. There is no switching surge & Power factor is maintained accurately. There are no
contactors & no complicated wiring.
3 PHASE STEP LESS POWER FACTOR CONTROLLER
STEP LESS –
THE HYBRID POWER FACTOR CONTROLLER
In this controller
both Variable
transformers &
APFC RELAY units
are built into one
to cut short the
cost.
While 3 Nos. of 1
Phase Power Factor
corrections with
three 1 Phase
Variable
transformers goes
to balance out the
differences in PF
of individual
phases, the relay
type units goes to
provide balanced
capacitor
correction.
Basically – the
unbalanced type
Power Factor
corrector with
Variable
transformers is
installed / can be
installed in addition
to EXISTING
POWER FACTOR
panels to even out
Power Factor
correction and thus
affect further
savings.