Stability analysis and energy storage-based solution of wind farm during low voltage ride through

According to most grid codes, wind farms are required to inject reactive current into the connected power gridduring fault. However, this requirement may lead to the system instability and the failure of low voltage ride-through (LVRT), especially for the wind farms connected to a weak grid. In this paper, we suppose that theinstability of wind farm during LVRT is mainly due to the instability of the phase-locked loop (PLL), thus a state-space model of the wind power system including the PLL under the low voltage condition is established forstability analysis. The mechanism of the system instability phenomenon during fault is investigated and revealed. To address this problem, an energy storage system (ESS)-based stability control strategy is proposed tomaintain the stability of the wind power system during fault. The detailed electromagnetic model of the testsystem including three wind farms is installed in PSCAD/EMTDC environment for simulation studies. Simulationresults verify the correctness of the obtained stability analysis results and the effectiveness of the ESS-basedstability control strategy