Frequency-Constrained Coordinated Planning of HVDC and Generation

High-voltage direct current (HVDC) technology has been extensively employed for long-distance transmission of renewable energy due to its advantages of high efficiency and controllability. However, large capacity HVDC lines can bring serious challenges to the frequency security of the power grids. Therefore, the planning of HVDC needs to match the frequency regulation capacity of the AC power grid. In this paper, a coordinated planning of HVDC and generation is proposed for renewable energy integration. For the optimal sizing of HVDC, the capacities of candidate HVDC lines are regarded as decision variables, and the investment model for HVDC is considered. The frequency security constraints under HVDC N-1 contingencies are extracted and embedded into the planning model. The case study validates that the proposed planning model can effectively guarantee frequency security under HVDC N-1 contingencies.