Abstract
Under the background of high wind power permeability, the frequency regulation capability of high voltage direct current (HVDC) sending-end system tends to deteriorate. For this reason, this paper regards the wind farm (WF) and HVDC as a combined frequency regulation system, and a fuzzy-based coordinated control strategy is proposed for the cooperation of HVDC and WF to participate in frequency regulation. First of all, at a system level, in order to realize the dynamic cooperation of the WF and the HVDC to participate in frequency regulation, two fuzzy logic controllers (FLCs) are designed to determine the total power support of the combined system and the participation coefficient of the WF in the frequency regulation according to the frequency characteristics of the sending-end system and the operation state of the WF, respectively. Secondly, at the WF level, considering the rotating kinetic energy and capacity of the wind turbines (WTs), a power allocation strategy is proposed to maximize the utilization of the frequency regulation capacity of the grid-connected WTs in WF. Finally, based on the fast power regulation of HVDC, an active secondary frequency drop (SFD) suppression strategy is proposed to avoid the possible SFD caused by the rotor speed recovery of WTs. The simulation results show that the proposed strategy can make full use of the frequency regulation ability of the WF and HVDC, and can effectively improve the frequency characteristics of the HVDC sending-end system.
Highlights
In order to deal with the energy crisis and carbon emissions, renewable energy has been developed rapidly
A fuzzy logic-based coordinated control strategy is proposed for enhancing the frequency response capability of high voltage direct current (HVDC) sending-end system with wind farm (WF) integration
Through the simulation analysis under different cases, the conclusions can be drawn as follows: (1) At the system level, based on the proposed control strategy, the WF can dynamically cooperate with HVDC to provide frequency support according to its own operation status
Summary
In order to deal with the energy crisis and carbon emissions, renewable energy has been developed rapidly. When the system frequency fluctuates, HVDC and WF provide a fast frequency response according to their respective frequency controllers The effect of this method on enhancing the frequency regulation capability of the sending-end system was proven through small signal analysis in [17]. ∆PSG, ∆PWF, ∆PLoad, and ∆PDC denote the active power change of synchronous generators, the WF, load, and HVDC system, respectively At this time, the frequency regulation resources in the sending-end system will respond to the frequency deviation. Assuming that a f-P droop control loop is added to both the WF and the HVDC control system, the active power support provided by the generation side in the sending-end system can be expressed as follows:. At the same time, the frequency response output characteristic of the sending-end system will be affected by the WF and HVDC
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