Viability analysis of HVDC light a case study of Tanga to Pemba Island

Many islands distanced from the mainland use expensive power generation using small and uneconomical plants which are also environmentally unfriendly. Pemba Island is currently supplied by National grid using HVAC submarine cable of 8MW. The fast development of power electronics based on new and powerful semiconductor devices has led to innovative technologies, such as HVDC Light, which can be applied to electric power transmission and distribution systems. The technical and economical benefits of HVDC Light technology represent an alternative to the application of HVAC systems. Some aspects, such as deregulation in the power industry, opening of the market for delivery of cheaper energy to customers and increasing the capacity of transmission and distribution of the existing lines are creating additional requirements for the operation of power systems. Alternating Current (AC) electric power system is the main driving force in the industries and residential areas, but for the long transmission line AC transmission is more expensive than that of direct current (DC) technically, this dissertation work presents a comparative evaluation of HVDC Light and HVAC transmission systems from Tanga to Pemba Island. Voltage Source Convertor based HVDC employing IGBT‟s that operates with high frequency PWM and d-q control technique is presented in this research work. Modeling and simulation results of HVDC Light system using MATLAB/Simulink are presented. The simulation results include when the system is at normal operation condition, three phases to ground fault and unbalance fault.