Abstract:According to the actual network failure caused by network storm in UHVDC control and protection system,the relevant mechanism is analyzed,three conditions are put forward to host crashes,and the causes of the accident are given,which ultimately leads to the DC bipolar blocking event. Through the system simulation analysis of the blocking event,it is found that the DCC800 host network packet screening detection function is not perfect,in the emergence of long packets of self lock it cannot be timely remind CPU to take measures to deal with serious defects. Therefore,in the protection of the host the length of the packet screening detection function is added,when the message is more than 255 bytes between the station and the control protection system,the host computer control system selects not to receive. At the same time,in order to verify the performance of the network and analyze the related accidents,the network testing schemes for the control and protection system of UHVDC converter station are proposed. The analysis of actual event shows the correctness of the analysis.