Lightning protection – where it matters most

by A Barwise, DEHN protection South Africa


Published in: Transformers and Substations Handbook: 2014

Chapter 2: Design and installation of a substation - page 40

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Protecting personnel in the event of an arc fault: An arc flash is part of an arc fault, a type of electrical explosion that results from a low-impedance connection to ground or another voltage phase in an electrical system. The light and heat produced from an arc flash can cause substantial damage or harm, fire or injury. There are many methods of protecting personnel from arc flash hazards – including arc flash protective equipment.

Lightning protection systems for substations and transformer stations: Lightning protection systems protect structures, including substations, from fire or mechanical destruction, and people in buildings from injury and death. The external lightning protection system is made up of three elements, i.e. air termination, down conductors and grounding systems. Internal lightning protection prevents hazardous sparking inside the building or structure.

Surge and lightning protection for electrical and electronic systems: A lightning protection system protects people and material assets of value in the buildings. It does not protect the electrical and electronic systems. Lightning up to a kilometre away can cause damage to sensitive and electrical and electronic equipment. Electronic equipment can be protected from the potentially destructive effects of high voltage transients by protective devices such as lightning barriers, surge arrestors, lightning protection units.


Take note

  • An arc fault is the most catastrophic event that can occur in an electrical enclosure.
  • Lightning does not have to strike a facility directly to do real damage.
  • Five safety rules are mandatory when working on electrical installations.