Aiming at the problem that the existing static equivalent method of power grid cannot accurately estimate the static equivalent parameters of multi-port network by using the limited historical measurement data of internal network. a static equivalent parameter estimation method of power grid based on limited historical measurement data is proposed. Firstly

for the conventional multi-port interconnection network

the extended voltage source Ward equivalent model considering the ground capacitance is selected to model the external network equivalent

and the external network equivalent parameter estimation model is constructed with the minimum power difference between the external network input to the internal network through the boundary node before and after the equivalent as the optimization goal. The equivalent branch parameters are within the allowable range as the constraint condition. Then

to ensure the reliability of parameter estimation

a selection method of internal network historical measurement data based on voltage-power sensitivity is proposed

which supplements the available internal network measurement data for the external network equivalent parameter estimation model without requiring unplanned operation of the power grid. Finally

based on the grey wolf algorithm

the iterative optimization of the external network equivalent parameter estimation model is realized

and a set of optimal external network equivalent parameters is obtained

so match the state quantity of the grid before equivalence. The simulation results of CEPRI36v7 system verify the correctness of the proposed method.