Interaction of lightning and other high power surges withintrinsically safe installations

摘要

It is demonstrated that heavy current surges from faults in powerelectrical equipment and lightning can theoretically create a transientproblem in intrinsically safe circuits. It is argued that in a wellbonded plant with adequate power and lightning earths then in Zone 1 and2 this slight transient risk is acceptable as existing installationsdemonstrate. In the particular case of Zone 0, acceptance of the Germanrequirement for galvanic isolation is advocated for the usual risk, andwhere there is a high potential risk of severe transient potentialvoltages then a more elaborate configuration similar to Dutch practiceis commended. It is believed that these proposals are a practicalcompromise and might remove one major obstacle to creating a uniformEuropean Code of Practice