Over the last few decades, the Progress Energy Carolinas (PEC) service territory has been one of the fastest-growing areas in the United States. To meet this demand, PEC needs to plan, design, construct and retrofit power transmission substations. Reliable operation of a substation requires accurate relay logic design and installation. This in turn underscores the need to produce accurate and detailed protection and control (P&C) construction drawings to mitigate any error precursors and misinterpretations. To achieve these deliverables, a robust engineering process and versatile design tools are imperative.

In addition to PEC's growing demand for power substations, there are industrywide initiatives such as smart grid and distribution supervisory control and data acquisition (D-SCADA) that have increased the P&C engineering workload exponentially. When employing traditional engineering design processes with limited resources, it is not practical to deal with this workload effectively. As a result, PEC's transmission operations and planning department has designed, developed and implemented the Relay Automation Program for Intelligent Drawings (RAPID) process to standardize and automate the P&C engineering design process. The objective of this effort was to eliminate latent design errors, shorten project lead times, enhance quality and elevate the production rate.

Previous Process

To complete the P&C engineering design phase, PEC uses a wide variety of processes. Two design processes have been identified for improvement: three-tiered data entry tasks for project drawing information and multiple data duplication of relay logic data.

The title blocks of project drawings require specific information, including project name, drawing type, drawing title, revision information, drawing number for organized record keeping and drawing identification. This information is entered in a drawing transmittal form (DTF), which lists all the drawings required for a given P&C design project. DTF enables construction personnel to quickly retrieve the appropriate drawing for a relay panel, major equipment installations, wiring and functional testing.

To facilitate this need, the project drawing information entered in DTF also needs to be entered in each computer-aided design (CAD) drawing title block. To perform this task, each drawing used in a project requires the project drawing information to be entered manually, one at a time. This involves significant time and effort. The project CAD drawings are stored in a document management system (DMS) for centralized accessibility, future reference, asset maintenance and potential expansions.

For organized storage and future retrieval of CAD drawings, the project information needs to be entered a third time into the DMS for the corresponding project. Because of this requirement, the user must manually enter the project drawing information as DMS attributes for each drawing.

On the whole, during the life cycle of the project design, any changes to the project information requires the user to manually update the DTF, CAD drawings and DMS attributes, leading to labor-intensive and duplicative processes. With this process in place, there was an urgent need for process improvement to achieve efficiency gains.

Relay logic data is required for reliable and safe substation operation. The criteria for relay logic design are based on the substation configuration, protection scheme, voltage class, existing schemes and application methodology. To control and monitor functional components of a substation, several standard relay panel types have been established, including line, bank, bus, capacitor and tie-breaker panels. A relay panel contains a combination of Schweitzer Engineering Laboratories (SEL) relays and additional hardware. PEC uses SEL-300 and SEL-400 series relays extensively in its transmission P&C engineering design processes.

Several individual relays are used to create the P&C functional (logic) drawing. Each relay used in the functional drawing has its own settings sheet and dc elementary drawing. The relay logic data is primarily designed in the settings sheet. Subsequently, the former data is entered in functional and dc elementary drawings. For instance, a line panel functional drawing consists of the SEL-311C backup relay, SEL-321 primary relay and SEL-351S breaker relay. The user manually enters relay I/O data in individual relay settings files, functional drawings and dc elementary drawings. Also, the line number, breaker number, voltage class, bus number, bank number and so forth must be entered several times. The result is a redundant, highly error-prone and cumbersome process.

A Friendly Solution

To meet the previous process challenges, PEC developed and implemented the RAPID process to streamline P&C engineering design processes. Custom-built toolbars were designed within the CAD application for quick accessibility to various design elements and design tools to produce project-specific P&C drawings. The RAPID process is bifurcated into RAPID I and RAPID II, each providing the solutions to the unique challenges imposed by the conventional processes outlined previously.

To enhance the transmission P&C engineering design process, the RAPID tool provides many features:

  • Interface to enforce standardization
  • Graphic access to relay drawing templates
  • Intuitive relay engineering design process
  • Expedited changes during the design phase
  • Data sync to CAD drawings
  • Single-tiered data entry
  • User-friendly design tools.

RAPID I

RAPID I was devised to eliminate the existing three-tiered data entry of project drawing information in the P&C engineering design process. The premise is to enter the project drawing information in DTF, which should automatically synchronize the corresponding CAD drawings title block information and DMS attributes. To design this automated solution, intelligence was applied to the DTF, drawing title blocks and DMS attributes.

Project drawing information changes made in the DTF are now automatically synchronized to the drawing title block, which in turn synchronizes the DMS attributes. This improvement eliminates three-tiered data entry and embraces single-tiered data entry.

RAPID II

RAPID II streamlines and eliminates the multiple data entry of relay logic data in the P&C engineering design process. This solution enables the user to enter the relay logic data in the settings sheet. The data is transferred to the relay's functional and dc elementary drawings automatically.

Settings sheet templates for various relays have been created in Microsoft Word. Since each relay consists of multiple boards, the I/O data tables for each relay have been categorized into main board and extra board. Intelligence was applied to the data tables to facilitate data transfer to any application easily. Within each settings sheet template, a graphic user interface was developed to populate the I/O fields in the data tables. The fields are based on the project parameters such as voltage class, line, bank, bus, tie-breaker and panel locations in the substation. Designing the relay logic data using the graphic user interface was quick, intuitive and user friendly.

Relay functional templates have been established to create drawings for various applications including line, bank, bus, capacitor bank and tie-breaker panels. Based on the application, the user creates the drawing by selecting the required template from the pre-built design library.

Each SEL relay used in the relay functional drawings requires a dc elementary drawing to show how the equipment is electrically connected and functions in the protection circuit. A centralized design library with predefined dc elementary templates for the SEL-300 and SEL-400 series relays were developed. The RAPID II GUI provides a click button to access the templates from the design library.

Benefits

Application of the RAPID process provides several benefits during the P&C engineering design phase. Historically, design tasks such as entering the project drawing information and the relay logic data in the relay drawings were time consuming. The RAPID process reduced the time required to complete the former design tasks, which directly translates into significant cost savings. Also using the RAPID process, engineers can consistently produce accurate and detailed drawings, all to the benefit of the organization.

Annually, there are about 50 projects in which RAPID I is employed. Each project has about 100 relay drawings, for a total of 5000 drawings per year. The use of the conventional process for drawing generation takes more than 15 minutes per drawing. RAPID I requires less than a minute per drawing. At first, this may not seem significant. But on an annual basis, RAPID I improves productivity by saving about 1200 hours, a cost savings of about US$65,000.

Similarly, there are about 50 projects in which RAPID II is employed on an annual basis. Each project has about 10 relay drawings, for a total of 500 drawings per year. The use of the conventional process for drawing generation takes more than 2.5 hours per drawing. RAPID II requires about 15 minutes per drawing. On an annual basis, RAPID II improves productivity by saving about 1125 hours, a cost savings of about $62,000. Thus, the bifurcated RAPID process is expected to generate in excess of $120,000 per year in savings by increasing productivity by an order of magnitude.

Acknowledgements

The authors extend special thanks to PEC's Mick Vander Ploeg, director of project management, and Rhonda Webb, transmission maintenance manager, for envisioning and laying the platform for a design-automation strategy in the transmission operations and planning department. Thanks also goes to Bill Newell, a principal engineer in Standards & Technical Specifications, Eddie Williamson, senior engineer, and Tom Williams, manager of P&C engineering, for their unparalleled and continuous support that resulted in this project's success and fruition.

Process Number of projects annually Number of relay drawings per year Time using conventional process for drawing generation (per drawing) Time using RAPID process for drawing generation (per drawing) Annual productivity saved (in hours) Annual cost savings (U.S. dollars)
RAPID I 50 5000 15 minutes < 1 minute 1200 65,000
RAPID II 50 500 2.5 hours 15 minutes 1125 62,000
$127,000

Shiva Korremla (shiva.korremla@pgnmail.com) is a mechanical engineer at Progress Energy. His job responsibilities include standardizing and automating the transmission engineering design processes through visual basic programming, database concepts and other process improvement techniques. He received a MSME degree from The University of Texas at El Paso.

Pam Kermon (pamela.kermon@pgnmail.com) is an engineering support specialist in the P&C engineering unit at Progress Energy. Her job responsibilities are to provide technical and electrical design work to the P&C engineering unit. Her scope of work also includes the smart grid initiative, training and identifying process improvement opportunities within P&C engineering design processes. She has working experience of more than 20 years at Progress Energy.

David Webb (david.webb@pgnmail.com) is a senior engineer in the P&C engineering unit at Progress Energy. His job responsibilities include creating project scopes and conceptual designs, project estimates, designs, settings and test instructions for in-house and contracted projects for transmission and generation projects. He received a BSEE degree from North Carolina State University.

Mike Kirkland (mike.kirkland@pgnmail.com) is the manager of the transmission technical specifications and standards unit at Progress Energy. He fostered the design-automation strategy, foreseeing the potential tangible and intangible benefits to the transmission engineering units and the organization as a whole. His role is to monitor and control the design-automation projects by providing required resources. He received a BSEE degree from Auburn University.

Company mentioned in this article:

Schweitzer Engineering Labs www.selinc.com