Power system engineers all face a similar dilemma at one time or other when trying to identify which product offers the quality they require – especially in today’s global market with its many competing suppliers.

As surge protective devices, arresters mitigate the impact of events that might otherwise trigger outages and monitoring them has become part of an industry-wide trend toward greater condition assessment of key network components.

Two types of fault currents can appear on power systems: ground and phase-to-phase. The more important when it comes to surge arresters is the first, which is basically the current that flows through the circuit when there is a short to ground.

American Transmission Company (ATC) own and operates transmission lines in the States of Wisconsin, Michigan, Minnesota and Illinois. The system originally belonged to local utilities that had different standards and this resulted in a variety of different line surge arrester installations at 69 kV and 138 kV.

What is the kJ/kV Uc rating of a Class 1, 10 kA arrester? This type of question has often been asked when it comes to distribution arresters. Yet finding an answer was never easy since these arresters (formerly referred to as Class 1) never had energy ratings.

At some point, all electrical equipment has an end-of-life-event (EOLE). Sometimes this event can be as benign as being removed and replaced with a newer device, but it can also be the by-product of a thunderous overload.