This paper expounds the communication structure of control and protection system for the HVDC project

and finds that the communication systems has the problem of high load rate in board PCIF through in-depth analysis of abnormal start case. An optimization method that through modifying software event operation cycle to achieve lower load rate in board PCIF is put forward

which has been verified in practice. Finally

the further optimization and improvement scheme is provided to fundamentally resolve the problem of communication abnormality

so as to improve the reliability of the DC control and protection system.