In order to enable the permanent magnet synchronous generator (PMSG)-based wind turbine (WT) to capture more wind energy while providing fast frequency supports effectively during disturbances, this paper proposes a time-sharing frequency coordinated control (TFCC) strategy. Firstly, a rotor virtual inertia control and a DC-link virtual inertia control are presented, and a new adaptive frequency droop control considering frequency deviation is proposed. Secondly, a novel TFCC strategy, which uses the frequency dead-band to coordinate the frequency regulation priority of above three controls, is proposed. With the proposed strategy, the electrostatic energy stored in the DC capacitor is always first utilized for frequency support, while the rotor rotational kinetic energy is only applied when the DC capacitor energy is used up. Finally, the control performance is studied in PSCAD/EMTDC, whose results indicate that the TFCC has better performance in terms of wind energy harvesting and system stability as compared to traditional coordinated control and cascading control, respectively.

With the continuous increase of renewable energy generation and high voltage direct current (HVDC) power transmission, the system inertia is declining, thus resulting in greater risks of frequency instability. To solve this issue, a dc‐link inertia control is firstly proposed for a point‐to‐point modular multilevel converter based HVDC (MMC‐HVDC) link, which enables the MMC‐HVDC system to provide emulated inertia support by employing the electrostatic energy stored in the dc capacitors. Moreover, in order to maintain reasonable submodule capacitor size as well as provide more emulated inertia support, a virtual capacitor control for MMC‐HVDC connected an offshore wind farm (OWF) is proposed. With the virtual capacitor control, the OWF is able to provide a large capacity virtual capacitor in dc side of MMC‐HVDC link and supply desired emulated inertia support for onshore power system by utilising the offshore wind turbines’ rotor rotational kinetic energy. Furthermore, a procedure for selecting the appropriate virtual capacitor control parameters is proposed. Finally, the performance of the proposed coordinated control is researched in PSCAD/EMTDC, and the simulation results show that the onshore power system inertia is effectively improved with the coordinated control.

Against the crippling assault of power grid, the impact of cyber attack on line-commutated converters based high voltage direct current (LCC-HVDC) system is investigated in this paper when the false data injection (FDI) attacks its control loops. Based on the basic control strategy of LCC-HVDC, the impact on each HVDC control mode is investigated when FDI occurs, including the rectifier side constant DC current control and supplementary damping control, the inverter side constant DC voltage control and constant extinction control. Through the theoretical analysis, it is found that the rectifier side FDI attack would limit the power transmission and increase HVDC’s reactive power demand, which will finally lead to instabilities, where the damping ratio could also be decreased if the rectifier supplementary damping control is attacked. Another important fact is that the inverter side attack could have much more severe impact when the false data is injected because the inverter extinction angle may be decreased and causes commutation failures. The above analysis and conclusions are validated by the simulations finally.

China is taking initiative in energy transition to cope with the long-term controversy of its enormous energy consumption, aiming to use less carbon. Wind power, especially offshore wind energy, has become a prevailing alternative due to its low carbon emissions, renewability, competitiveness, and operation security. The layout of a transmission channel is a key consideration in marine project implementation. This paper investigates the technical characteristics, application status, and viable advantages of a conventional AC transmission, voltage source converter-based high-voltage direct current (VSC-HVDC) transmission, gas-insulated line (GIL) transmission, and hybrid HVDC transmission. A component-resolved evaluation model was proposed to estimate the costs to be incurred of four electrical transmission options for offshore wind power along the coast of Eastern China, with technical feasibility and economical considerations. Cost comparisons and component sensitivity analyses were developed with different transmission distances and capacities. Results suggest HVAC transmission and VSC-HVDC are the preferable solutions for present offshore wind farm development in Eastern China, and the economic potential of the hybrid HVDC makes it feasible for future deployment. Some conclusions can be applied in disparate regions across the globe.