*Article* **Use of AMT Transformers and Distributed Storage Systems to Enhance Electrical Feeding Systems for Tramways**

### **Romano Giglioli, Giovanni Lutzemberger \* and Luca Sani**

Department of Energy, Systems, Territory and Constructions, University of Pisa, 56122 Pisa, Italy; romano.giglioli@unipi.it (R.G.); luca.sani@unipi.it (L.S.)

**\*** Correspondence: giovanni.lutzemberger@unipi.it; Tel.: +39-050-221-7311

Received: 18 August 2020; Accepted: 8 September 2020; Published: 10 September 2020

**Abstract:** Tramway systems are more and more di ffused today, to reduce pollution and greenhouse emissions. However, their electrical feeding substations can have significant margin for improvement. Therefore, it is questionable which kind of changes can be introduced, by changing their main features. First of all, transformer technology can be enhanced, by moving from the standard transformer to the amorphous metal one; thus, guaranteeing a significant reduction in losses. Then, by installing one dedicated storage systems for each substation. This solution can help to increase the energy e fficiency; thus, recovering the tram braking energy and reducing the delivered energy from the grid, and also the reliability of the system; thus, guarantee di fferent levels of services, in the case of failure of a feeding substation. This paper investigates in a systematic approach the two proposed solutions. In particular an amorphous metal transformer has been properly designed, and performance compared to the standard one. Then, evaluation of distributed storage installation was performed, and the aspects of reliability for these systems evaluated. Results have shown the general feasibility of the proposed solutions, showing a significant energy saving with respect to the conventional ones.

**Keywords:** amorphous transformer; energy storage; failure; feeding substation; tramway
