In order to improve the voltage stability of the grid connection point and reduce the commutation failure rate

the line communicated converter based high voltage direct current (LCC-HVDC) system uses a static synchronous compensator (STATCOM) to compensate for reactive power in the converter station. However

with the large-scale integration of renewable power

the power grid strength gradually weakens

and the stability problem of LCC-HVDC converter station systems containing STATCOM in weak power grid environments is becoming increasingly prominent. This article proposes a stability improvement method for LCC-HVDC converter stations with STATCOM in the weak grid

based on the synergy of admittance reduction and phase compensation. First

this paper employs a small signal method to establish the admittance model of the converter station in the dq coordinate system. Then

based on the characteristics of the LCC and STATCOM admittance models

a method for improving the stability of the converter station is proposed. That is

the admittance remodeling factor is introduced into the control loop of the LCC to reduce its admittance amplitude

making it more difficult for the characteristic value trajectory of the system’s return ratio matrix to surround the (1

0) point. The negative damping interval of the admittance element is further eliminated through the phase compensation of STATCOM to provide positive damping for the system

thereby enhancing system stability. Finally

the reshaping method is validated through Matlab/Simulink and RT-LAB experimental platforms

demonstrating the effectiveness of the proposed approach.