It is necessary to study the impact of large-scale wind turbines with virtual inertia control on power system stability considering the effects of frequency measurement. The phase-locked loop (PLL) measures the frequency of the power system. The PLL is deteriorated when grid voltage contains sags, unbalance, high harmonics, and sudden drop frequency, and it is lead to problems of the PLL to track the frequency of the grid voltage. In this paper, adaptive complex least mean square (ACLMS) algorithm is used for estimation of the grid frequency. The ACLMS is an adaptive filter, which can track frequency deviation, accurately and rapidly.