Whole transformer station protection and automation-a local area network approach

The authors introduce an approach to whole transformer substation protection and automation. It describes a local area network (LAN) technique which is especially suitable for power system automation. The LAN permits the interconnection of protection systems, fault recorders, and the host computer. The host computer coordinates the functioning of the equipment in the whole substation, passes any messages from protection relays or fault recorders to a remote control room. The control staff can interact through the host computer with any relay or recorder to effect a change or interrogate the equipment. The LAN uses BITBUS interconnection standards with an isolated dual-host computer with an advanced bus. The system can transmit at a rate of either 375 kbps or 62.5 kbps over a maximum distance (without repeater) of 1200 metres