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| Why
Does Power Get Polluted? |
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Most
of the present day loads are inductive loads (For
instance computer loads, induction motors, power
transformers, lighting ballasts, welding furnaces
etc.) This causes poor load current phase angle
and results in poor power factor at the point
of utilization.
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Many
loads like rectifiers, variable speed drives,
switch mode power systems and other kinds of electronics
loads distort the current waveform substantially.
This results in large current harmonics in the
networks. This harmonic current is a scourge for
all loads connected in the networks as well for
the utility. |
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| This
Pollutions Causes |
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Higher
maximum demand charges and higher tariffs. |
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Overheating
of all upstream and downstream current carrying
cables and components. |
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Higher
wear and tear of all components/equipments and
hence premature ageing of such components/cables. |
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Stray
tripping of breakers and protection relays. |
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Under
utilization of utility power source, as reactive
power use up the capacity with otherwise could
have been used for serving the load. |
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Flickers,
sags and surges. |
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| Benefits
of Power Management |
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There
are considerable direct savings for a company by improving
the power quality. Poor power factor not only attracts
penalties from the utility company, but can also amount
to disconnection of the power itself. Drawing power
at unity input power factor has attractive incentives
from the utility and maximum demand charges are also
reduced considerably. However, major savings come in
the form of higher utilization of source, reliable operation,
(and) increased life of all connected components/equipments
in the distribution network. |
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| There
are stringent standards of compliance applicable today: |
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IEC
61000-3-2 Limits for harmonic current emissions,
equipment < 16A |
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IEC
61000-3-4 Limits for harmonic current emissions,
equipment > 16A |
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With
the privatization of electrical utility companies, the
standards are followed more vigorously.
Further, harmonic current generated also polluted and
cause problems to the neighboring industries when you
are sharing a common distribution transformer; a common
practice is industrial complex and multistoried complex.
It also loads the distribution transformer with reactive
power demand allowing connected users to utilize only
a portion of the capacity of the distribution transformer.
Above all these, poor power factor and harmonics makes
the power generating stations to circulate wasteful
power to support large quantum of reactive power demands,
which is a national waste.
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| MANAGE
POWER WITH DATAGUARDTM |
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|
ePFC
(Active Power Factor Controller) |
|
H-Filters
(Active Harmonic Filters ) |
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| ePFC |
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ePFC
is an active solid state power factor controller capable
of correcting both distortion power factors, compensating
the reactive current drawn by the load with a priority
to correct displacement power factor. ePFC, with adequate
sizing, improves the power factor to near unity (>0.99)
dynamically. Since it is an active compensator, compensating
both inductive and capacitive (+and-) is achieved. This
avoids dangers of resonance and over compensation like
in thyristor switched capacitor banks. Power factor
capacitors are fully eliminated in this configuration.
Systems can also be programmed and set to provide a
specified PF if desired.
ePFC is available in different ratings from 75 KVAR
to 200 KVAR. The connection is in shunt path with three
CTs installed to the 3 phase network, at the point of
correction/compensation required, generally at the output
of premises metering. The systems are simple and capable
of paralleling up to 4 units in a group from a common
CT (200KVA x 4, even different ratings can be paralleled),
allowing modularity of scaling to required rating as
well subsequent augmentation of the equipment ratings.
The three phase network will also get balanced to a
large extended after installation of ePFC equipments.
If higher capacity is required, it can be achieved by
installation of additional CTs and group of ePFC. |
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| Hybrid
ePFC |
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ePFC
can also be connected in parallel with a fixed capacitor
bank. The fixed capacitor bank can be sized to meet
a portion of the AVR demand and balance can be provided
by ePFC. Since ePFC can compensate from minus (-) to
plus (+) dynamically, the corrected PF will be near
unity. This kind of configurations can reduce the cost
of installations. This will also be an ideal way to
connect a ePFC to an existing installation of fixed
capacitor and achieve near unity PF, harmonic contents
in the network are generally negligible. |
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| H-Filter |
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Dataguardtm
offers a wide range of Harmonic Filters. These are DSP
controlled equipments using IGBT as switching devices.
The harmonic compensation is provided till the 40th
harmonic with excellent dynamic response. These are
ideal for all kinds of applications wherein high harmonic
currents are present. Installation of adequately sized
H-Filters can completely nullify the harmonic problems
in the network.
H-Filters
are available for both 3 wire and 4 wire network. Networks
with predominantly single phase based loads, primarily
in large computer installation sites, the neutral currents
pose problems. H-Filters can be installed to compensate
harmonics in the entire network or specific load depending
on the point of connection.
The
system also balances the three phase currents and improves
the input power factor. Many H-Filters (equal or unequal
ratings) can be connected in parallel to meet the adequate
rating demands as well progressive demands through time. |
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| TECHNICAL
SPECIFICATIONS |
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