distributed network protocol (smart grid) (DNP)
The Distributed Network Protocol (DNP3) is an open standard compliant communication protocol for telecontrol. The DNP3 protocol is used for communication between outstations, remote control terminals( RTU), Intelligent Electronic Devices( IED) and the central control station, the master. It is suitable for Supervisory Control and Data Acquisition( SCADA) in electric power plants as well as in power generating and distributing smart grids.
DNP3 is an open, robust and efficient Scada protocol that can carry a wide variety of data types in a single message, as well as segmented messages in multiple frames. In addition, DNP3 has excellent error correction and recovery, where only the transmission of modified messages is sufficient. Besides prioritizing messages, there is also the possibility of generating responses without special requests. DNP3 supports multi-master and peer-to-peer operation and allows user-defined objects and file transfer.
Using the DNP3 protocol, the master station can use predefined control functions to make requests to the outstations, which answer them. In the update of DNP3 there is a mechanism for authentication with which the master station can uniquely assign the correct outstation with which it communicates.