Smart transmission system by HVDC and FACTS

Nowadays, more than ever before, electric power becomes fundamental to modern society's existence. The power demand for electricity has been growing very fast during the last decades with a high impact on global climate and environmental conditions. The answer is grid access of large amounts of Renewable Energy Sources (RES), e.g. wind and solar technology. This, however, makes the power systems more complex and consequently changes the grid structure: the linear energy chain, consisting of large centralized power plant with excellent control features (“power on demand”), is rapidly becoming a complex power matrix with Dispersed Generation (DG), of which many are installed on medium and even low voltage levels. Such a grid structure must be “Smart”. For this reason the smart transmission system is a big challenge for the necessary system stability and reliability requirements of the Grid Code. Innovative solutions with HVDC (High Voltage Direct Current) and FACTS (Flexible AC Transmission Systems) with LCC (Line-Commutated Converter) and VSC (Voltage-Sourced Converter) technology play an important role in the smart transmission to enable bulk power long-distance transmissions and grid access of RES, to reduce transmission losses and CO
₂
emissions, to interconnect countries and even continents for an open electricity market and to improve the transmission stability. In this paper, the benefits of the HVDC and FACTS technology for transmission system enhancement are discussed and project applications are presented.