Office Building Solution

BU I LDI NG SOLUT IONS

8

— Power quality

— The disturbances of greatest interest affecting the operation of an electrical component or user are:

— Origin and effects of power quality disturbances.

• long or short duration power interruptions due to faults in the network; • Voltage variations of short duration due to the insertion of heavy loads or faults in the network; • dissymmetries in the power supply voltage system; • flicker due to large intermittent loads; • the distortion of currents and voltages due to the effect of non-linear loads present in the same system or in the systems of other users, etc.

Disturbance Frequency Variations

Origin

Effects

Disconnection of large generators Switching of large loads Faults Generator set operation Insertion of loads Loads with variable absorption Natural overvoltage Interruption and disconnection

Speed variation in motors Malfunctioning of electronic devices that use frequency

Rapid voltage variations

Untimely intervention of protections Flicker (if the variations are repetitive) Malfunctioning of electronic equipment Irreversible equipment failures Irregularities in the operation of motors Malfunctioning of electronic equipment Improper intervention of relays Malfunctioning of protections Increase in copper losses Increase in dielectric losses Increased iron losses in electrical machines Unstable operation of motors Interference on telecommunication circuits Irreversible damage to power factor correction filters Aging of components

10,70%

Buchi di tensione Voltage dips

Voltage dips and short interruptions

Faults Transients

23,60%

Interruzioni brevi Sho t interruptions

Buchi di tensione

Interruzioni lunghe Long interruptions

Harmonics

Non-linear loads Variable speed drives Fluorescent lamps Static converters Arc furnaces Welders

Interruzioni brevi

Armoniche Harmonics

Interruzioni lunghe

Sovratensioni urges

29%

%

Armoniche

Altro O her

Sovratensioni

18,80%

Altro

Impact of the origin of power qua- lity-related disturbances on costs excluding outages (source LPQI).

5,40%

12,50%

Dissymmetry

Unbalanced loads

Overheating of rotating machines and rectifiers

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