In a DC substation， one physical device， such as a control system or a protection system， needs to control both high voltage and low voltage equipments in the substation. There are many status and control modes specific to HVDC system not included in IEC 61850 standards. The paper discusses the IEC 61850 modelling approach for HVDC control and protection system. The model includes event logs， remote control， remote modulation， remote measurement and remote communication. For the protection system modelling， the object oriented method is used. The model of protection action matrix（PAM） in IEC 61850 standards is also given. The extensions of logical node type and data object class are also discussed.