Packet Analysis of DNP3 protocol over TCP/IP at an Electrical Substation Grid modelled in OPNET

In this paper Intelligent Electronic Devices (IED) that use ethernet for communicating with substation devices on the grid where modelled in OPNET. There is a need to test the communication protocol performance over the network. A model for the substation communication network was implemented in OPNET. This was done for ESKOM, which is the electrical power generation and distribution authority in South Africa. The substation communication model consists of 10 ethernet nodes which simulate protection Intelligent Electronic Devices (IEDs), 13 ethernet switches, a server which simulates the substation Remote Terminal Unit (RTU) and the DNP3 Protocol over TCP/IP simulated on the model. DNP3 is a protocol that can be used in a power utility computer network to provide communication service for the grid components. It was selected as the communication protocol because it is widely used in the energy sector in South Africa. The network load and packet delay parameters were sampled when 10%, 50%, 90% and 100% of devices are online. Analysis of the results showed that with an increase in number of nodes there was an increase in packet delay as well as the network load. The load on the network should be taken into consideration when designing a substation communication network that requires a quick response such as a smart gird.