Key Players Covered Some of the major companies that are present in global transformer service market are ABB, Eaton, Schneider Electric, Siemens, GE, Honeywell, KONÄŒAR Group, Hyundai Power Transformers USA, Qualitrol, hioTron, Mitsubishi Electric Automation, Inc., Lumasense, Dynamic Ratings, Creative Micro Systems, and Power Substation Services.