In this paper

the current status and future development plan for the south power grid in Suzhou is firstly introduced. On that basis

the existed problem of voltage stability of the south power grid in Suzhou is studied

the voltage instability mechanism is analyzed

the main factor influencing voltage stability is summarized and such measures as the installation of dynamic reactive power compensation device is proposed. Through the study and verification of such three normally used dynamic reactive power compensation device as phase modifier

static var compensator（SVC）and static synchronous compensator（STATCOM）in their principle

allocation scheme and influence to the power grid after connection

the conclusion and optimization suggestion on solving the voltage stability of the south power grid in Suzhou is proposed. A set of STATCOM compensation device with 300 Mvar will be installed in Wujiang in 2020

which can improve voltage level after fault recovery of system and maintain voltage stability during N-2 fault in the south power grid of Suzhou.