Electrical disturbances in LV

Improving the quality

LV networks are highly polluted and subject to a large number of aggressions. Electrotechnical equipment and in particular electronic devices, that are increasingly numerous and process ever lower signals, must withstand a harsh electromagnetic environment. At the same time availability requirements, whether for production, management or commerce, are increasingly great.

To improve the quality of the “electricity product” and avoid malfunctioning and in some cases destruction of the components of the electrical network and/or sensitive loads, it is essential to understand the origin of the disturbances and evaluate their risks. This is the purpose of this “Cahier Technique”, which is an introduction to the vast field of electromagnetic compatibility and immunity from 50 Hz through to radioelectric frequencies.

In this document the author deals with all parameters and their main “anomalies” used to characterise an electrical supply:

• amplitude: variations – interruptions – dips – overvoltages,
• frequency: variations,
• waveform: harmonics – transients – carrier currents,
• phase: unbalance,
• power: short-circuits – overloads (effects on voltage).

LV industrial voltages

All networks undergo or create disturbances. However, loads, as well as control/monitoring and protection devices, are sensitive to the quality of the voltage applied to them. Knowledge and consideration of these electrical power supply requirements are thus justified:

Manufacturers of electrotechnical and electronic equipment designed for an international market must allow for tolerances that vary from country to country.

AUTHOR: Schneider Electric expert | Roland CALVAS