Invasion of high voltage direct current till 2014

Electrical power system is an intricate network of transmission lines and its complexity is consistently increasing with induction of distribution generation (DG) which is nonlinear in nature. One of major problem with remotely generated electrical energy is of reliable transportation to ever increasing load center. A solution must be capable to deal with controllable components of power and one strong recommendation is high voltage direct current (HVDC). HVDC is conspicuous substitute to conform high voltage alternating current (HVAC) for bulk power transmission as well as renewable energy resources. In this paper, a comprehensive overview of advances in HVDC technology, its architecture based on line commutated converter-LCC and Voltage source converter-VSC, reliability assessment regarding adequacy and security, HVDC switch gear, control of VSC based Multi terminal HVDC and comparison of different HVDC topologies has been presented.