Impact of offshore wind farms to the Brazilian interconnected power system

This paper focuses on the impact of gigawatt-scale offshore wind farms to the Brazilian Interconnected Power System. The paper presents a case study on the connection of 3 GW to a single point in the Brazilian system considering a planned scenario for the year 2032. The selection of the point of common coupling is chosen according to the strength of the point given by its short-circuit ratio, and by the location of the wind farm projects envisaged by TotalEnergies EP Brasil S.A. AC transmission is considered. Positive-sequence and phasor-domain load flow and transient stability analyses, considering the whole Brazilian system, indicate overvoltage problems at the point of common coupling and its vicinity, particularly when the wind sags and there is too much headroom in the subsea cables. The paper shows strategies to mitigate the overvoltage problems that considers fixed and controlled onshore reactive power compensation, the possibility of cable disconnection in low-offshore-wind scenarios, and the operation of the wind farms with a lagging power factor. The paper shows a computational framework to automate the computation of short-circuit capacity of candidate hosting substations, and to automate the onshore generation redispatch to accommodate the gigawatts injected by the offshore wind farms, in selected system future scenarios. The framework uses a Phyton script that coordinates the call of two commercial-grade tools officially utilized by the Brazilian planning and operating entities. The paper also introduces an optimization framework, utilizing a combination of metaheuristics methods, designed to create a computational tool aiding planners in selecting the optimal configuration for connecting offshore wind farms to the Brazilian system.