Active harmonics
conditioners from 20 to 480 Amps
Invisible,
costly pollution
Nonlinear loads absorb currents.
All currents are made up of:
>
the basic sinusoidal current (50 Hz, for example) called the
fundamental (F),
> sinusoidal "polluting"
currents which are multiples of F (2F, 3F, 4F, 5F, ... nF )
called harmonics.
These harmonics are increasingly polluting the voltages used
by production facilities, pumping stations, data processing
systems, telecommunication switchboards, TV studios, etc. and
consume a significant proportion of available current.
This gives power users three types of problem: |
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> Impact
on the electrical installation with
significant overheating in alternators, transformers, capacitors and
cables ... The hidden costs of accelerated ageing in this type of
equipment can be extremely high.
>
Impact on utilisation of equipment
with unexplained power outages and malfunctions in equipment sensitive
to power quality. These failures cost money and reduce the effect
of capital investment - with a negative effect on the bottom line!
> Impact
on available electrical power as the
current consumed by harmonics is totally lost and can cause up to
30% over-consumption. Utility bills soar even though there is less
power available.
Existing standards
Three sets of standards
designed to reduce the spread of harmonic pollution now apply.
These are:
Standards for equipment
>
IEC 1000-3-2 or EN 61000-3-2 for low voltage appliances absorbing
currents of under 16 A,
> IEC 1000-3-4 or EN 61000-3-4
for low voltage appliances or installations absorbing currents exceeding
16 A.
Standards for mains supply quality
>
EN 50160 defines the voltages supplied by utility low voltage networks,
> EEEI 519 (Recommended Practices
for Harmonics Control in Electrical Power Systems) is a joint recommendation
by utility operators and subscribers to limit the impact of non-linear
loads through a joint effort to reduce harmonics.
Compatibility standards between electrical
networks and products
>
IEC 1000-2-2 and recommendations by CIGRE (Conférence Internationale
des Grands Réseaux Electriques) for public low voltage networks,
> IEC 1000-2-4 for industrial
installations using low and medium voltage. Utilities actively encourage
preventive actions to reduce electricity quality depreciations and
overheating, and to increase the power factor.
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International
