Electric Utility Engineers have Traditionally Employed 2-D Computer-Aided Design (CAD) drawings to design substations, even after better technology was developed. Utilities have largely ignored advanced CAD tools, especially 3-D modeling features, even though they are the norm in many industries. For instance, the manufacturing industry has been using 3-D CAD models with associated bill-of-material (BOM) information in its design plans for years.

Progress Energy Carolinas (Raleigh, North Carolina, U.S.) believes the electric utility industry should follow similar processes. Progress Energy is in a good position to reap the benefits of the advanced technology as steady growth in the Carolinas leads to increased demand for electricity, which means building new substations. The utility currently serves 1.4 million customers in North Carolina and South Carolina over a 34,000-sq mile (88,060-sq km) service territory.

GROWTH FUELS DEMAND

To satiate growing demand, Progress Energy must plan, design and construct additional infrastructure including new substations and system-capacity increases. With an eye on cost and a commitment to quality of service, the utility requires detailed engineering drawings and concurrent design data reports. Accuracy and automation of CAD drawings helps to eliminate misinterpretations and construction delays during the project construction phase.

Automation of design and detailing with intelligent 3-D modeling instead of 2-D drafting is beneficial in enhancing engineering and production activity. In order to automate design and detailing, a system must be intelligent.

The Substation Modeling and Automation using Relational Database Technology (SMART) system, developed in Progress Energy Carolinas' Transmission Operations and Planning department, meets this challenge of intelligence. SMART system functionality provides a range of capabilities, including:

• Intelligent 2-D/3-D CAD models for automatic generation of BOM reports

• Synchronization of 2-D sectional and plan view drawings with a single 3-D substation model

• Initial project estimate using intelligent one-line circuit diagrams

• Flattened 3-D models that can be used with existing substations

• Automatic updating of BOM information on standard drawings using pivot table technology.

THE CONVENTIONAL PROCESS

The method most utilities follow for substation design can add unnecessary time, cost and frustration. It usually incorporates two separate processes: an industry-standard 2-D CAD application for plan preparation and a standard BOM database for material and equipment information. These work-flow sequences typically require a user to manually search drawing indices and design data, which results in a cumbersome information-retrieval process.

According to substation engineering personnel, finding, retrieving and manipulating BOM data reports consumes the majority of effort for a project. All construction drawings are in a 2-D nonsynchronized format. For example, a breaker shown in the plan view is a totally separate element from the same breaker shown in the elevation view — even though both represent the same piece of equipment. Each occurrence of a design element must be updated separately from the rest. The result is a time-consuming and potentially error-prone process.

Additionally, standard construction drawings include static BOM information. This crucial catalog of parts and compatibles needs to be accurate for proper installation and future reference. Part changes in the warehouse database need to be updated on several sheets manually, making the process of drawing production and accuracy inefficient.

If savings of time and effort can be realized, then productivity can be maximized, errors can be minimized and duplication can be eliminated — all to the benefit of the organization. These motivations led Progress Energy to envision, design and develop the SMART system.

THE SMART SYSTEM

The primary objective of the SMART system is to provide linked data in the system that can respond to changes seamlessly and with minimal effort. To enable this dynamism, Progress Energy used 3-D parametric CAD models and linked them to appropriate database records. The utility designed the 3-D models from existing 2-D vendor and standard substation designs, then created 2-D and 3-D cell libraries. A cell library is a collection of 2-D and 3-D CAD models of standard equipment and structures that are used repeatedly.

Next, Progress Energy linked the cells to the corresponding data in the centralized database to create intelligent cell libraries for the user. Users choose the cells from these cell libraries to create and modify 3-D substation models. The designs then project specific construction drawings and plan views to generate a project BOM report automatically. Use of these pristine, intelligent cell libraries by end users enforces adherence to standards and informational consistency, which eliminates ambiguities. Figure 1 depicts a virtual 3-D model (a template) of a standard T&D-class substation that was built using cell libraries.