Changing patterns of demand that new types of load such as electric vehicles (EV) will introduce large and unpredictable fluctuations in the power balance as well as variations in voltage can jeopardize the quality and availability of power. The T&D system has to be stronger and smarter to provide the real-time flexibility needed to efficiently handle the new conditions. Investment needs in the power T&D infrastructure are large and require long term planning and deployment. The environmental concerns and public acceptance issues that often arise when constructing additional conventional transmission lines will require more efficient solutions with lower environmental impact.

This Discussion Paper from ISGAN Annex 6 Power Transmission & Distribution Systems Task 3 and 4 focuses on “Smarter & Stronger Power Transmission” and is a review of feasible technologies for enhanced transmission capacity and flexibility in terms of status and deployment. This includes both the primary AC and DC technology for the high voltage transmission grid as well as the information and communication technology (ICT) required to efficiently supervise and operate the power system. Focus is on the development of power electronics including flexible AC transmission (FACTS) and high voltage DC (HVDC), the standardization within ICT such as IEC 61850 and Common Information Model (CIM) in order to obtain vendor independent interoperability as well as the progress of wide area monitoring, protection and control (WAMPAC). The combination of smarter ICT applications together with power electronics such as FACTS and HVDC can be described as a digitalization of the power system operation offering the required flexibility. Most of the examples given are from the Nordic European power system, reflecting the participation of the authors from ISGAN Annex 6 Task 3 and 4, with additional input from North America and selected International case studies.