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PRODUCTS
Low Voltage Equipment |
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PRODUCT GUIDE TO LOW VOLTAGE PRODUCTS |
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Nokian Capacitors compensation
equipment helps customers improve performance through energy savings and
better power quality. With our products and solutions customers save
money and reduce the environmental impact of their operations.
Nokian Capacitors compensation
equipment includes a wide range of standard products and one-off
solutions at low voltage levels. We analyze your needs and engineer the
right solution for optimal efficiency and economy.
Product guide to low voltage products (.pdf) |
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ACTIVE FILTER MAXSINE |
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There is an increasing number of electrical
equipment with non-linear voltage-current characteristics connected to
the network. Harmonic currents produced by them cause harmonic voltages in
network impedances, which add to the fundamental system voltage
resulting in voltage distortion. This voltage distortion is experienced
by all electrical equipment connected to the network leading to higher
thermal loading of motors, transformers, capacitors, switchgear and
cabling. Some of the electrical equipment develop more audible noise
when supplied with distorted voltage. Sensitive electronic protection,
control and ripple control systems are likely not to operate properly
when supplied with distorted voltage.
The most effective way to eliminate harmonics
is MaxSine, active filter. Nokian Capacitors’ MaxSine is based on
patented Direct Phase Current Control (DPCC) technology. It provides
your network with efficient and fast harmonics reduction and reactive
power compensation.
Active filter MaxSine (.pdf)
Active filter MaxSine website |
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DW-SERIES DETUNED FILTER CAPACITOR BANKS |
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Nokian Capacitor DW-series automatic
capacitor banks with blocking reactors are intended for power factor
correction in systems where harmonic distortion is present.
New modular and compact design provide space
saving and flexible mounting options for wall or floor mounting. DW-series
is available in two variants, standard and extension. Extension types
includes space for fast and easy power extension. Reactive power
compensation is controlled with high performance reactive power
controller N-6.
DW-series detuned filter capacitor banks (.pdf) |
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WALL MOUNTED AUTOMATIC CAPACITOR BANKS |
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Automatic capacitor banks are used for
central power factor correction at main and group distribution boards.
Power factor correction means that reactive power charges levied by
electricity suppliers can be avoided. Automatic capacitor banks consist
of stages controlled by a power factor controller which ensures that the
required capacitor power is always connected to the system. In
wall-mounted automatic capacitor banks all components (capacitor units,
contactors and fuses) are built into a compact steel enclosure. This
makes installation easy and capacitor banks can also be easily expanded
if necessary. Expansion is allowed for in the cabling recommendations.
When power ratings in excess of 100 kvar are
required cubicle type automatic capacitor banks are used. When selecting
compensation for a system which contains a harmonic generating load,
check the automatic capacitor bank is suitable for the purpose. In
systems where harmonics are present, compensation must be by means of an
automatic capacitor bank with blocking reactors (de-tuned filter) or a
harmonic filter (tuned filter).
Wall mounted automatic capacitor banks (.pdf) |
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CUBICLE TYPE AUTOMATIC CAPACITOR BANKS |
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Cubicle type automatic capacitor
banks are modular in structure. All the components for a single stage
(capacitor unit, contactor and fuses) are built into one module. This
makes maintenance very easy and the capacitor banks can also be easily
expanded. Expansion is allowed for in the cabling recommendations. In
the case of larger banks (over 300 kvar) the modules are installed as
sub-banks in several cubicles with a shared reactive power controller.
In this case each cubicle requires its own fused feeder at the
distribution board.
Cubicle type automatic capacitor banks (.pdf) |
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AUTOMATIC DETUNED FILTER CAPACITOR BANKS |
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Power transmission and distribution systems
are designed to operate with sinusoidal voltage and current waveforms at
a constant frequency. However, when nonlinear loads - such as thyristor
drives, converters and arc furnaces - are connected to the system,
excessive harmonic currents are generated, and this causes both current
and voltage distortion. Power factor correction by means of conventional
capacitor banks is not possible in systems affected by harmonics. This
is because the harmonic-currents are amplified in the parallel resonant
circuit formed by the capacitor and the network. As a result current and
voltage distortion are further increased.
When harmonics are presented in the system,
power factor correction should be implemented by means of automatic
capacitor banks with blocking reactors. Each step of the bank consists
of a capacitor unit with a blocking reactor. These form a series
resonant circuit tuned to a frequency below that of the lowest harmonic.
Wall mounted automatic detuned filter capacitor
banks (.pdf)
Detuned filters (.pdf) |
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HARMONIC FILTERS |
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Harmonic filters consist of
capacitors connected in series with a reactor. Capacitors produce
reactive power at the filter's fundamental frequency ant the circuit is
designed to achieve the required power factor correction. The inductance
of the reactor is chosen so that the filter forms a very low impedance
series resonant circuit at the harmonic frequency. This ensures that a
high proportion of the harmonics enter the filter. A typical harmonic
filter consist of three series resonant circuits tuned to the most
common harmonics (5th, 7th and 11th harmonics). The filters are housed
in steel cubicles. Each consists of a contactor, thermal over current
relay, reactor and capacitors. The unit is generally connected to the
fused feeders on the main distribution board.
Harmonic filters (.pdf) |
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THIRD HARMONIC FILTER |
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Nonlinear one-phase loads such as
fluorescent illuminators and computers which are connected between phase
and neutral are generating third harmonic and multiple of it. All
harmonic currents cause both current and voltage distortion. In addition
to this third harmonic currents accumulate in the neutral wire
increasing the risk of overloading and caused magnetic field having
frequency of 150 Hz. By filtering third harmonic from the network the
above mentioned problems can be eliminated.
3rd harmonic filter consists of capacitor
units which are connected in series with reactors. The harmonic filter
produces reactive power at fundamental frequency in order to reach the
target power factor. The inductance of the reactor has been chosen to
create very low impedance series resonance circuit for 3rd harmonic. As
a result of this most of 3rd harmonic current can be filtered. The
filter cubicle has a contactor, a thermal overload relay, reactors,
capacitors and a voltage control relay.
Third harmonic filter (.pdf) |
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THYRISTOR SWITCHED CAPACITOR BANKS (TSC) |
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Thyristor switched capacitor banks equipped
with a fast control are designed to support the line voltage and to
compensate the reactive power of the load. Thyristor switches make
possible that a fast response is achieved without any mechanical wear,
noise or excessive transient associated with contactor switching. A
control signal can be brought from the compensated equipment and so it
is achieved reactive power compensation almost without delay. All steps
of the capacitor bank are switched on during one network period. Each
step of the bank consists of a capacitor unit with a blocking reactor.
These form a series resonant circuit tuned to a frequency below that of
the lowest harmonic.
Capacitor bank is chosen to be suitable for
load according to the control system, compensation power and load
switching. The compensated equipment can be symmetrical or unsymmetrical
for main or phase voltage switched loads.
Thyristor switched capacitor banks (.pdf) |
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FIXED DETUNED FILTERS |
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Fixed detuned filters are used to compensate
the reactive power in individual, standard-power devices or groups of
devices in networks affected by harmonics.
A fixed detuned filter consists of a reactor
connected in series with the power capacitor unit. With this
construction a resonance phenomenon between network inductance and
capacitor capacitance is avoided.
A fixed detuned filter is usually connected
in parallel with the device or the group of devices to be compensated.
In this way, the capacitor is switched on and off simultaneously with
the load. When necessary, a contactor can be installed inside the box in
a case when the detuned filter is wanted to be controlled separately.
Fixed detuned filters (.pdf) |
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