How are Surge Arresters Classified.

Surge Arresters are classified based on their rating, the amount of energy to be dissipated and their application. 

Surge Arresters are classified into three types.

Station Class Arresters

Station Type arrestors are used in substations where the equipments are connected to the Transmission lines.  These arrestors are designed to discharge high amounts of energy and have elaborate systems of pressure relief.  They are used for equipments whose rating is above 20 MVA

Intermediate Class Arresters

These are used for Transformers and rotating machines of 1 - 20MVA.  Intermediate Class Arresters are a compromise between reliability and economy.  Typical examples of applications would be dry type transformers, switching and sectionalizing equipment. 

Distribution Class Arresters

Distribution Class arresters are used in transformers and rotating equipment with a powe rating below 1000 kVA.  These arresters are used on exposed lines connected to the equipment.