Choosing the right surge arrester(s) is a key factor to guarantee correct protection of the installation. A poorly designed Lightning & Surge protection system may lead to early ageing of the SPD and potential failure of the protective devices in the installation allowing damage to the primary systems up stream, thus defeating the rationale behind the protection being installed.
Prosurge does not provide a set of rules and guides to support acorrect design of the protection system according to the application. However we follow the IEC and UL lightning and surge protection standards. With this in mind we provide a cascaded system as laid down in the rules of the standard, not the rules of Prosurge.
In the field of industrial applications, a standard practice is to install a cascaded protection system based on several coordinated protective devices installed at different stages (LPZ’s). The benefit of this strategy is the fact that it allows a high discharge capacity close to the installation entrance along with a low residual voltage (level of protection) at the main incomer of installation of sensitive equipment.
The design of such a protective system is, amongst other factors, based on the assessment of information such as existence of a lightning rod (Lightning Protection System) and type of incoming power supply lines, secondary primary equipment and data systems.
The solutions provide protection against either Transient or Permanent (TOV) overvoltages or against both of them (T+P) simultaneously.
The final product choice depends on parameters such as: type of installation, type of network disconnection (operation on MCB or RCD), auto reclosing, breaking capacity, etc.
Usually you can refer IEC61643- Low-voltage surge protective devices – Part 12:Surge protective devices connected to low-voltage power distribution systems -Selection and application principles