Colorado Interstate Gas Company has developed a fully integrated Gas Control Planning System. It incorporates an automatically dialed weather forecast service, a gas load forecaster, a gas supply manager with storage scheduler, and an extensive computerized SCADA system. The output of these programs plus real-time data make up the input to steady-state and transient flow pipeline models that provide the Gas Controllers with a 48- hour forecast of pipeline operations. This paper describes the development and implementation of the project, the development of the load forecaster and supply manager programs, and use of the system by Gas Controllers for daily operations planning. It includes descriptions of the menu system, reports, and graphical output.
Colorado Interstate Gas Company (CIG) was formed in 1927 and began operations in 1928. Its original function was moving natural gas from the Texas Panhandle to Colorado Fuel and Iron Company in Pueblo, Colorado, and to the city of Denver, Colorado. The company is headquartered in Colorado Springs, Colorado. In 1973, CIG became a subsidiary of Coastal States Gas Corporation, now The Coastal Corporation, with headquarters in Houston, Texas. CIG operates as a federally regulated interstate transmission company with major gas supplies in Wyoming, Utah, Colorado, Kansas, Oklahoma, and Texas. The principal markets are along the Front Range of the Rocky Mountains from Cheyenne, Wyoming, to Raton, New Mexico. Figure 1 illustrates CIG's pipeline in its supply and market areas. CIG operates over 6,000 miles of pipeline and over 324,000 horsepower for gas compression. Approximately one-half of the pipeline mileage is for transmission and the remainder is for gathering and storage. Similarly, about one-half of the compression horsepower is for transmission and the remainder is for gathering and storage. CIG has developed and operates four underground storage facilities: three in eastern Colorado and one in western Kansas. These storage fields can supply a peak-day volume of 550 MMcf per day and an annual volume of 30 Bcf. The locations of the storage fields are indicated by triangles on Figure 1. In addition to its role as principal supplier of natural gas to the Rocky Mountain Front Range, CIG has become a major transporter of gas for other gas producers and pipeline companies. In 1987, 60 percent of the gas transported by CIG was Transportation & Exchange (T&E) volumes. OPERATIONS CONTROL BEFORE CURRENT PROJECT In the late 1970s and early 1980s, CIG adopted and implemented a distributed data processing and control philosophy. Eight DEC PDP 11/23+s and 11/24+s were established at widespread district field locations. We call these computers Remote Masters (RMs). The RMs gather data from Remote Terminal Units (RTUs) installed at key locations along the pipeline. The RTUs are incorporated in CIG's in-house-developed Supervisory Control and Data Acquisition (SCADA) system.