Bridging SCADA Islands: A Solution for the Distribution of Information and Commands Among Geographically Separate Control Centers

This paper describes a gas transmission pipeline company with dissimilar local control and Supervisory Control and Data Acquisition (SCADA) systems that had formed over time, and the solution that was put into place to consolidate those systems. Great Lakes Gas Transmission Company (GLGT) had historically operated the pipeline from four geographically different locations with a combination of various local man-machine interface (MMI) control systems and an aging SCADA system. As new control systems were installed at compressor and meter stations, local and corporate data acquisition needs changed. It became apparent that the existing SCADA system which telemetered a minimal set of control data could no longer support growth requirements. The decision was made to replace the old SCADA system with a new “open” state of the art architecture. As a result of competitive bidding, the Valmet OASyS (Open Architecture SyStem) was selected and installed at multiple locations along the pipeline. Each system was connected with a Wide-Area-Network (WAN) and an application which enabled information to be shared among the locations. Operators may view information from any location along the pipeline, and may remotely control devices from authorized locations. In addition, the corporate office in Detroit, Michigan was given the capability to view information from the entire pipeline for administrative and planning purposes. The system installed at Detroit now functions as a gateway for information exchanged between GLGT’s parent companies.