After the operation of 1 000 kV Xiaoxiang-Ganjiang UHV AC double circuit line

the transient voltage stability characteristics of Hunan power grid have been significantly improved. However

due to the mismatch between power supply construction and load growth

there are still voltage stability problems in Hunan power grid in wet and heavy load periods.Distributed synchronous condenser can provide strong moment of inertia and fast reactive power support for the system

and it is an important technical means to solve the problem of voltage stability of the receiving end power grid. Firstly

this paper compares the transient voltage support effects of different voltage levels in different substations in central and southern Hunan

and obtains the optimal configuration scheme of the condenser in Hunan power grid. Then it is proved that after the central China UHV AC loop network is put into operation

the new condenser can improve the transient voltage stability level of the power grid

release the standby of thermal power units and replace the startup of thermal power units

so as to play a great role in improving the Qi-Shao DC power transmission capacity

the overall power supply capacity of the whole province

the clean energy consumption capacity and the flexibility of power grid operation mode.