HVAC Transmission System for Offshore Wind Power Plants Including Mid-Cable Reactive Power Compensation: Optimal Design and Comparison to VSC-HVDC Transmission

The design distance of offshore wind power plants connected through HVAC transmission systems might be extended due to the introduction of mid-cable reactors for reactive power compensation purposes and the latest developments of AC cables for higher voltages. Therefore, the applicability limits between HVAC and HVDC systems must be revised. This paper analyzes the contribution that mid-cable reactive power compensation has on increasing the distance limits of HVAC transmission systems. A methodology is developed to determine an optimal design of such transmission systems. In this methodology, cost of power losses and reactors are minimized for multiple wind speed conditions. As a result, the optimal HVAC voltage level and the optimal number of reactors and their location are determined for different OWPP rated powers and distances. Also, the final transmission system is selected between HVAC and HVDC equivalent configurations based on total costs.