In recent years，wind-turbines have been required to possess the fault ride-through capability，especially the low voltage ride-through（LVRT）during grid fault.It has been included in the latest grid codes of many countries.The paper firstly analyses the grid code requirements on the wind farm grid connection in this regards and then the doubly fed induction generator（DFIG），a popular type of wind turbine，is taken as an example to explain the key points of LVRT technologies，from the viewpoint of secure grid-connection，reactive power support and optimized operation.Finally，the current technologies are reviewed and compared in order to present the latest progress in the LVRT technologies，and discusses its future possible development.