Fast peer-to-peer real-time data transfer can be solved in two ways. One way is to use GOOSE which has very low latency. GOOSE is a relatively mature technology used in substation automation systems, but its configuration is based on Media Access Control (MAC) addresses, resulting in higher configuration requirements for project implementation; and its communication interaction coverage is limited to the same local area network, which affects the workload of distributed control applications. Another way is to use the User Datagram Protocol (UDP), which is widely used for fast data transmission over an Ethernet network. Theoretical analysis and test results show that the transmission delay of UDP mode is not larger than that of SMS transmission if the network traffic is less than 5 Mbps, which can fully satisfy the time delay requirements of distributed control applications. The priority of UDP packets is the same as the priority of communication data (mostly in TCP transmission mode) from the master station. If the network delay is highly dependent on the network load, UDP packets may be lost under heavy network traffic conditions, and therefore, fast peer-to-peer real-time data transmission between STUs cannot be guaranteed.