Progress Toward Substation LAN Reported at DistribuTECH(TM)
The local area network (LAN) is a promising communications method for electric utility substations but there are no ideal, obvious solutions, reported Ron Farquharson, manager of the substation automation business segment for GE/Harris, at the recent DistribuTECH Asia conference in Singapore. Few substations, even those that are automated, have LANs, he pointed out, even though they offer a good way for linking intelligent electronic devices. A problem is lack of industry LAN standards.
Farquharson said two LAN standards are gaining the most interest among utilities and vendors in North America: Ethernet and Profibus. “Although neither of the LAN standards entirely meets all of the U requirements, both are very economical solutions,” Farquharson said. He reported that although no ideal solution has been identified, GE/Harris has chosen the following LAN technologies and protocols:
Application Layer: DNP 3.00, MMS, Telnet, FTP.
Presentation: Null or implied by application layer.
Session: Null or implied by application layer.
Transport: UDP And TCP.
Network: Internet Protocol.
Data Link: IEEE 802.2 Logical Link Control Type 1, IEEE 802.2x Media Access Control.
Physical: IEEE 802.3 Ethernet.