Abstract: The voltage support capacity of the centralized onshore wind farms is weak, and the active power transmission distance is often long. With the increase of their active power generation, the voltage stability of the system cannot be ignored. For the voltage oscillation instability phenomenon caused by the low voltage ride through (LVRT) control mode in the actual power grid under no fault condition, this paper analyzes the mechanism of the phenomenon based on a simplified model and extends criteria applicable to multi-machine systems. In theory, the phenomenon corresponds to high output excited low voltage ride through control induced non-smooth Bifurcation (HLINB), and the boundary conditions of HLINB and Saddle node bifurcation (SNB) is analyzed. In criterion, based on the second-order cone algorithm, the critical criterion of HLINB is given. Specifically, based on actual cases, the onshore wind farm voltage oscillation phenomenon caused by the LVRT control under no fault is analyzed, which indicates that the oscillation phenomenon corresponds to HLINB. Further, the boundary conditions of HLINB and SNB are derived. The results show that under the typical LVRT control mode of the onshore wind farms, wind farms with high active power output are more prone to experiencing HLINB rather than SNB in the actual power grid. Secondly, the influence of other wind farm reactive power control methods on the maximum active power output of the wind farm to be evaluated is analyzed. Also, based on the second-order cone algorithm, considering the reactive power control methods and reactive power constraints of the wind farms, the calculation method of the maximum active power output of the wind farm with HLINB constraints is given. Finally, the simulation examples of 3 machines 9 buses and 10 machines 39 buses show that as the proposed method considers the control mode of the wind farms, it can more effectively evaluate the voltage stability of the system.