Frequency-Voltage Synergy Support Method based on Grid Strength for VSC-MTDC Integrated Distributed Offshore Wind Farms

The emerging offshore wind farms (OWFs) with increasing installed capacity have an increasing impact on the frequency and voltage stability of onshore power grids. It is a challenge to enable OWFs to participate in frequency and voltage regulation considering the support ability of distributed OWFs and the anti-disturbance ability of onshore grid-connected nodes. To address this challenge, a frequency-voltage synergy support (FVSS) strategy for VSC-MTDC integrated distributed OWFs is proposed with four components: 1) A distributed coordination strategy with leader-follower consensus algorithm is developed for WTs to fairly provide support power; 2) An active/reactive power quantification strategy, which considers equivalent impedance characteristics of local loads and line power flow influence, is established for power requirements of ground side voltage source converters (GSVSCs) for frequency support (FS) and voltage support (VS); 3) A frequency strength quantification (FSQ) and voltage strength quantification (VSQ) strategies are conducted to characterize the anti-disturbance ability of GSVSC; 4) An adaptive power coordination strategy, which considers FSQ and VSQ, is proposed to achieves active/reactive power allocation for FS/VS. Extensive simulation results have validated the effectiveness and correctness of the proposed FVSS under different scenarios.