In order to ensure the safe and stable operation of energy storage power station

this paper studies the influence of grid-side impedance

multi-machine parallel line impedance and the number of parallel units on the safe and stable operation of the energy storage power station. Moreover

by establishing a mathematical model of the system

the stability of the system is verified through the eigenvalue root trace method. Firstly

a three-phase grid-connected model is established. Then

by using Norton's equivalent principle

the grid-connected equivalent circuit of single and multiple energy storage converters(PCS) is established

and the multi-machine parallel model transfer function considering line and network impedance is obtained. On this basis

the influence of parallel station number

line impedance and network impedance on the system stability is analyzed

and the correctness of this theory is verified by building a multi-PCS parallel simulation model in Simulink platform.