Power Flow Controlling Devices as a Smart and Independent Grid Investment for Flexible Grid Operations: Belgian Case Study

The electric power system in Europe is fundamentally changing, due to the liberalization of the energy market, the internationalization of electric power system operations, the shift towards renewable energy sources and the increased difficulty to install new transmission lines. The transmission system operators face new problems and they require new means to solve them. One option is to resort to the use of power flow controlling devices to manage the energy flows in the transmission system and to provide a secure operation under varying circumstances. Through the use of power flow controlling devices, the TSO gains a double advantage: investments in new (overhead) transmission lines can be avoided and it allows more flexible grid operations. This paper describes the Belgian case for different stages of the grid management: investment, planning, scheduling and operations using power flow controlling devices, including practical aspects. The Belgian case study comprises two technologies: the traditional phase shifting transformer and voltage source converter HVDC, each with their advantages and disadvantages.