International Journal of Science and Research (IJSR) ISSN (Online): 2319-7064 Volume 2 Issue 12, December 2013 www.ijsr.net HVDC and Facts in Power System S. Mohamed Yousuf 1 , M. Siva Subramaniyan 2 1 P.G Scholar (Power system), Prist University/S, India 2 Assistant Professor, EEE, Prist University/S, India Abstract: The development of electrical power supplies began more than hundred years ago. At the beginning stage, there were only small DC networks within the local boundaries, which were able to cover of industrial plants. An increasing demand on energy, technology changed to be transmitted from DC to AC power and voltage levels. The driving force for the development of power systems is the increase of electrical power demand. Therefore, power system developed from the regional to national systems. To achieve technical and economic advantages, extend further to large continental systems by applying interconnections to the neighbouring systems. This paper will treat benefits of HVDC and FACTS devices applied in power systems such as increased power transmission capability, improved static and dynamic stability, an increase of a availability and a decrease of transmission losses by using power Electronics techniques. Keywords: Development of HVDC & FACTS, Current status of power electronics techniques, Future development of HVDC & FACTS. 1. Introduction The development of power system is increased demand for electrical energy in industrial countries. In next 20 years, the power consumption is developing and emerging countries is expecting more than double [1, 2]. The basic energy consumption of driven factors is shown in figure 1. As an energy demand growth, high voltages are needed. In industrialised countries, the demand level is increased. There is a gap between transmission capacity and actual power demand, which leads to technical problem in the system like voltage problem, stability limitation etc. This problem can be solved by using interconnection of separated grids. In large AC transmission and synchronous interconnection, technical problems can be expected [3, 4]. Figure 1: Energy driven factor diagram This problem is achieved by using Power electronic devices such as IGTO, IGBT and HVDC light etc., and then the power system will be improved. The main idea of FACTS and HVDC can be explained by the basic power flow concept for transmission in fig 2. Figure 2: Basic power flow diagram for power transmission 2. Development of HVDC HVDC has been introduced in the second half of the past century for long transmission area. The magnitude of transmission power is increased (from few hundred MW into 3-4 GW) by using proper HVDC connections. Basically, back- back and two terminal long distance schemes are used. However, multi terminal HVDC scheme is planned for the future system [3, 5]. The design is illustrated in fig 3. Figure 3: HVDC connections HVDC became a more reliable technology by these developments HVDC transmission has been installed Paper ID: 02013570 133