The Adaptability Study Of The Third Defense Line After UHV AC/DC Access To Jiangxi

According to the demand for electricity of Jiangxi Power Grid and the overall planning of Central China Power Grid,the State Grid Corporation of China is going to construct the UHV AC and DC projects.It is predicted that the Yazhong-Jiangxi±800kV UHVDC project will be putting into operation in 2020,and construct supporting Nanchang convertor station;In 2021,it is also predicted that Jingmen-Wuhan-Nanchang-Changsha-Jingmen 1000kV UHVAC loop network project of the Central China Power Grid will put into operation.After UHV AC/DC put into operation,the maximum voltage level of Jiangxi Power Grid will be continuously spanning from 500kV to 1000kV,the single UHP AC grid architecture will also be transformed and upgraded to UHV AC/DC hybrid grid,all aspects of the grid will change dramatically,such as the UHV AC/DC links up to the grid will greatly complicate the characteristics of AC/DC coupling,dropping the damping torque/inertial level and voltage stability characteristics,the power grid's ability to respond to failures will decline and so on.The recovery capacity of the power grid will also decrease when it is disturbed by serious faults,it is more prone to happen massive blackouts.The safe and stable running of Jiangxi Power Grid will face unprecedented challenges.As the security and stability control system for the extreme emergency state,the third defense line of the power grid can take the most effective and direct measures to relieve the failure when electrical system subjects to the disturb of type III severe fault in order to prevent large-scale blackout and power grid crashes.So carry out the fault simulation of the Jiangxi Power Grid before the UHV AC/DC accessed,research whether the existing configuration of the third defense line in Jiangxi Power Grid can effectively relieve the failure when serious faults occur in Jiangxi Power Grid and make power grid recovery stable operation rapidly have a vital significance.This paper modeling Jiangxi Power Grid which is based on the planning of Jiangxi Power Grid in 2021 and simulating dead-zones fault,middle switchgear malfunction and Yazhong DC crossing fault by PSASP simulation software.The simulation results test and verify that the Hubei-Jiangxi tie line splitting,generator cutting,load shedding and other measures which belong to the security and stability control system of the third defense line can solve most of faults,but there are still some faults that the existing configuration can not solve,we need to take a further improvement for the third defense line on the basis of specific situation.