Why a Grounding System?

“A Grounding System is essential to limit the risk to people, equipment and system to operate within acceptable levels”.

The fault current that flows in the earth can cause a considerable (GPR) Ground Potential Rise on earthing system causing the Touch Voltage, Step Voltage and Transferred Voltage which are the three important parameters to assess the safety of substation earthing.

Without understanding the real complexity of an earthing system and also the lack of specific legislations and researches, history has demonstrated that installed earthing systems are often not adequately safe, sufficiently well configured to ensure personnel safety. Although the situation tends to be better with the publication and updating the several guidelines, code of practice, rules, standards, earth grid software, technical papers by researches and electricity regulations.

There is also an increased awareness of the risk of death or serious injury due to electrical shock by asset owners and the public. Safety by design is therefore paramount at all installations and requires innovative earthing solutions for a wide variety of possible soil profiles.

The table on this page shows some typical overhead line fault rates that can be used to calculate the Risk Assessment.

It is essential that the earthing be properly designed, correctly installed, and regularly tested and maintained to ensure compliance with Australian Standards, safety regulations, relevant laws and other reference document.

By Paulo Araujo & Ian Gray – Protech PAS