Often, the most costly aspect of operating applications is the maintenance of the network model and application database. As Orangeburg DPU examined maintenance costs in detail, it became clear that without an integrated approach to this implementation, costs would be repeated to support private databases and multiple models (of essentially the same distribution feeder network).

To trim both ongoing costs and the complexity of maintenance tasks, the utility needed a solution in which the model and real-time database would be common to all network-based applications.

With the selected applications, the source for Orangeburg DPU's network model is the geographic information system (GIS). Daily updates are made from an ESRI (Redlands, California, U.S.) GIS, the same source used by the outage management system. ACS's DASmap is used to extract the GIS model changes. Orangeburg DPU uses this to build connectivity and export a node-arc-node network model, automatically add the points to the real-time database and create the dynamic map display.

The new file changes are loaded daily into the real-time on-line DMS without downtime. This process takes from 30 minutes to four hours, depending on the size and complexity of the update. A new program version will soon handle incremental updates, speeding up the process as it provides automatic detection of GIS changes from one update to the next.

A Bright Future

To realize the SAIDI gains of the pilot program on a system-wide basis, Orangeburg DPU plans to increase the area under automation control. In the next phase, a feeder-loss minimization application will automate the control of the system's 57 capacitor banks. The power factor for each feeder will be calculated from the telemetered kilowatt and kilovolt-amp reactive. The load flow will be used to determine reactive power requirements at various capacitor bank locations, as well as for the entire feeder. This will be accomplished in real time, and the resulting capacitor switch commands will be presented as either operator action recommendations or automatically executed. Orangeburg DPU plans to add other applications in subsequent phases, including optimized switching, as well as intelligent switch-plan generation for planned outages.

Beginning with self-healing feeders, Orangeburg DPU is deploying an integrated suite of applications. Through careful management of adaptive, common model-derived applications, Orangeburg DPU is now poised to adopt additional applications to capture and sustain the gains in customer satisfaction along with increased reliability, flexibility and efficiency.

John Bagwell (jbagwell@orbgdpu.com) has served as director of the City of Orangeburg Department of Public Utilities (DPU) electric division since 1998. Bagwell came to Orangeburg DPU in 1987 as a control systems engineer, where he installed a SCADA system covering 23 electrical substations, two peak shaving generator plants, a gas distribution system, a 19-MGD water treatment plant and a 9-MGD wastewater treatment plant. He also installed a fiber-optic network consisting of OC3 backbone and 50 miles (80 km) of fiber cable, and was instrumental in installing the department's first personal computer network. Bagwell earned a BSEE degree from Clemson University and is president of the South Carolina Association of Municipal Power Systems.