Disturbances in electronic systems and earthing systems

Choice of earthing system

In today’s society, power and signal processing (analog, digital) electronics are omnipresent in all types of building. Information technology, automation control, hierarchical control and monitoring systems, weave a web around the electrical networks that supply them.

Although non-linear loads (rectifiers, variable speed drives, power controllers, switch mode power supplies, etc) create disturbances, low current electronic systems are affected by all kinds of electrical and magnetic disturbances. The choice of Earthing System is an important factor for electronic systems, especially when they use digital links (bus) to communicate.

This “Cahier Technique” first examines the disturbance found on LV installations and then looks at the advantages and disadvantages of earthing systems in terms of the cohabitation of “high” and “low” currents.

An electrical wave is characterized by:

• its frequency,
• its voltage,
• its intensity.

In the large supply networks of industrialized countries, the frequency is perfectly stable. It may vary when network splitting on a private installation involves the use of replacement sources, but this variation has little effect on the earthing systems and protective equipment required.

AUTHOR: Schneider Electric expert | Jacques DELABALLE