Step-down modification of 600 MW thermal power units transmission line

In Hunan Province,because most of the 600 MW thermal power unit outgoing line all access to 500 kV system,so in the high load time,the 500 kV bus is almost working at high load condition,this is not safe for network.In view of the above situation,a method that the 600 MW thermal power unit outgoing line access from 500 kV system to 220 kV system is introduced.A power company has successfully completed the project,and passed the safety evaluation.This experience can be a reference.