The interfacing of high voltage switchgear and distributed control system in a large cogeneration facility

The functional interface between a process-related distributed control system (DCS) and the high-voltage switchgear in a large cogeneration plant was accomplished using a programmable logic controller. A description is given of the project background, the overall system, interface selection considerations, development, and commissioning of this interface. It is shown that the controller was the only single equipment item which could perform all the required functions. Point costs were inexpensive, standard contact ratings were adequate, it was easily programmed, and, of particular importance, the direct data transfer to and from the DCS utilized identical protocol and was field proven