Phoenix Contact played host to the SAIMC Johannesburg branch on 17 August, with a thought-provoking presentation given by the company’s own Cameron Taylor. As the business unit manager for power solutions, Cameron put to educational use his seven years of industry experience specialising in the field of surge and lightning protection.
Surge currents and overvoltage impulses caused by lightning strikes or switching action can cause damage to sensitive electronic components and power networks, and thus reduce the availability of these networks significantly. The use of surge protective devices (SPDs) with a tailored protective function can effectively reduce the risk of damage caused by surge currents or surge voltages. To achieve this, the protection circuit needs to be adapted as much as possible to the application, and various types of protection mechanisms are commercially available to serve this end. Cameron’s presentation covered the aspects at play in these scenarios by explaining the methodology, fundamentals and design of application-specific surge protection circuits for power supply systems.
He went into detail about the three main categories of surge and lightning events, namely ESD (electrostatic discharge – low energy), SEMP (switching electromagnetic pulses – low to medium voltages) and LEMP (lightning electromagnetic pulse – high energy, in fact high everything…very high in many cases). Videos filmed at Phoenix Contact’s test laboratory in Germany illustrated these effects in graphic, destructive detail.
The protective device types (Type 1, 2 and 3) and the differences between them were examined, as were the coupling mechanisms employed, those being inductive, galvanic and capacitive. The primary takeaway was that a single protective device, or a single device type, is usually not sufficient to cater for most surge and lightning events. Instead, a cascaded approach is the wisest, and safest, course of action.
Questions from the audience included South African regulations and the confusion caused by various government bodies having their fingers in the same pie, as well as considerations for the growing solar photovoltaic (PV) market. Although the same electrical principles apply, complexity is compounded with PV installations since both AC and DC circuits need to be protected, as well as the batteries that store the solar energy.
Thanks go out to Cameron and the Phoenix Contact team for their hospitality and slickly presented, informative session.
| Tel: | +27 11 312 2445 |
| Email: | ina@saimc.co.za |
| www: | www.saimc.co.za |
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