This book contains articles [1-22] that were accepted for publication in a Special Issue of Energies on the subject of "Electric Power Systems Research". Customers request electric utilities to deliver electric power in a stable, reliable, secure, and sustainable manner from a generation system through transmission and distribution systems to end-users. Consequently, the need to develop advanced technologies and novel methods applied to the modern power system is essential. Recently, the concept of smart grids that incorporate renewable generation, power electronics-based facilities, and information/communication technologies has been receiving increasing attention. "Electric Power Systems Research" is a special issue of Energies for the publication of original papers about the generation, transmission, distribution, and utilization of electrical energy. This special issue presents important results of work on power systems. Papers can present applied research, the development of new procedures or components, an original application of existing knowledge, or new design approaches. Authors were invited to submit papers on "Electric Power Systems Research", including, but not limited to, the following areas: