The series electromagnet is energized by a coil known as current coil which is connected in series with the load so that it carry the load current. The flux produced by this magnet is proportional to and in phase with the load current.
Intern turn winding fault can be easily detect by differential protection relay. Also detect by buchholz relay (gas operated relay), cause buchholz relay is used to detect the internal fault of transformer.
The second generation of smart meters are known as SMETS 2. Full form of SMET is Smart Metering Equipment Technical Specifications. It is with the previous generation known as SMETS 1. SMETS 2 smart meters were introduced in 2018.