Optimal Design of Electric System for Off-shore Wind Power Plant (OWPP)

Abstract

In the recent years, due to land scarcity, off-shore wind power installations have been increased tremendously over on-shore installations. Beside its numerous advantages, high initial investment is the major concern of off-shore wind power installation and it is the main striking hindrance for its development. In view of reducing the investment and operational cost of electrical network integrating Off-shore Wind Farm (OWF) to on-shore grid, the paper proposes a novel Optimal Frequency AC (OFAC) transmission system, designed based on the computation of optimum operational frequency. The proposed system is economically competitive compared to High Voltage AC (HVAC) and Low Frequency AC (LFAC) system for moderate distant power transmission. The optimum operational frequency is the result of tradeoff between investment and operational cost of electric system. The paper presents a comprehensive methodology for the computation of optimum operational frequency for OWPP based on the criterion of minimization of installation and operational cost using Genetic Algorithm (GA). The proposed methodology is applied to an OWF of 160MW capacity. And for the off-shore distances of 50km, 100km, 150km and 200km, the optimum frequencies are obtained as 85Hz, 55Hz, 35Hz and 25Hz respectively. As compared to HVAC and LFAC, the proposed system validates its viability and profitability for the moderate distant power transmission and the results indicate that for the transmission lengths of 100 to 225km, the proposed system yields a saving of about 2 to 10% in the Net Present Value (NPV) of the system. Hence it is concluded that the paper presents a newer dimension for the economical design of OWPP based on optimum frequency and it helps in the promotion of off-shore deployment to the investors.