By Mike Lambert, Bentley Systems Inc.
Editor’s note: The following article is an adaptation of a paper that will be presented at DistribuTECH 2005 in San Diego, Calif., in the Power Delivery track on Wednesday, Jan. 26, at 9:30 a.m.
Computer-aided design (CAD) of power substations has become standard practice since the introduction of commercial computer-aided design and drafting systems in the 1970s. However, two-dimensional (2D) computer-aided design has been used almost exclusively in the utility industry to design and document the physical substation arrangement.
During the same time, other industries have adopted three-dimensional (3D) modeling for applications including process plant design and mechanical design. The benefits of 3D design and modeling in these industries are well acknowledged and documented: Concurrent engineering design, elimination of interferences (hard and soft), increased quality of design, accurate material requirements, faster project throughput, visualization and construction sequencing have all shown quantifiable benefits.
Clearly, the time is ripe for the utility industry to rethink substation design strategies. 3D modeling and content management technologies, combined with new implementation strategies that take advantage of other technologies, will shape a new generation of power delivery systems design and engineering for the coming decades.
Intelligent 3D Design
The basic concept of 3D substation design is to develop an integrated design model that includes the equipment arrangement, structures, foundations, control house, raceway, and grounding, as well as miscellaneous components.
The 3D model must:
- Be spatially correct;
- Include connectivity between components;
- Contain intelligent data about materials, engineering properties, physical details, stock numbers, compatible units and so on;
- Be linked to design database and functional design documents such as one-line diagrams;
- Provide information required to automate the extraction of drawings, schedules and cost estimates; and
- Provide a framework to integrate with both enterprise systems and engineering design and analysis applications.
To benefit from 3D, we must be able to provide users with tools to create new designs and modifications to existing substations. The goal is to automate the process of creating both standardized designs for reuse and unique designs based on advanced 3D modeling techniques.
From the Ground Up
Geospatial information technology can be used to support site selection and design processes. For example, the corporate geographic information system can be queried to determine possible substation sites optimized for line location, population density, environmental considerations, and so on.
A 3D civil site design application might design the site plan, including access road design, storm water retention features and other aspects of the site. Earthworks calculations, including accurate cut and fill, might be derived from the digital terrain model and site design information. Top soil volume may also be calculated.
The calculation of storm water runoff may also be used to design retention facilities. Templates might be provided for access road design, and both vertical and horizontal transport clearances could be calculated for moving heavy equipment such as transformers into place.
The resulting site plan can be referenced to the substation general arrangement.
Substation Arrangement Model
The substation arrangement can be designed by placing equipment, assemblies and materials from the libraries into an intelligent 3D model. Equipment and material definitions should also include details for design drawing extraction and compatible units.
Buses and connections with intelligent connectivity are also placed in the model. Structures and foundations can be placed separately or included in equipment assemblies. Electrical and working clearances are included in the equipment 3D definition. Interference or clash detection routines identify potential problems with the location of equipment, buses, structures, and foundations. Working clearances can also be inspected visually.
Equipment arrangements in the model are modified easily to adapt the design requirement to the site and optimize the design. Other modifications such as replacing equipment types or manufacturers are also quickly and easily accomplished.
From the model, we can extract accurate design drawings, material quantities, and equipment data in a fraction of the time required by manual drafting and design methods. Even isometrics may be automatically extracted and annotated from the model.
Future expansion plans can also be noted in the model. This ensures that future designs can be coordinated with expansion plans, and the expansion design can be rapidly and accurately completed as scheduled.
The resulting 3D substation models can be saved as standardized designs and reused. For example, standard distribution substation designs could be saved as templates. Then, when a new substation design is required, the appropriate template could simply be copied into the design for the new substation as a quick starting point. The resulting model could be modified for site-specific requirements and the design deliverables easily created.
Standardized designs can also be useful to provide rapid response to customer requirements such as proposing and designing dedicated substations for industrial, commercial and institutional clients. The requested design can be created and cost estimates quickly completed.
Unique designs such as those for transmission substations can be created from scratch, or designs can be incorporated from other substation models. As with standardized design templates, deliverable drawings and schedules can be quickly generated from the model.
Working with Existing Substation Designs
The majority of capital improvement projects today are for modifications to existing facilities. In these cases, a substation design application must work with existing drawings, either in vector or raster format, in order to modify the substation’s existing design. As such, it must include tools to work with vector formats (such as MicroStation or AutoCAD files), as well as raster files or electronically scanned drawings that are maintained in a raster format. These drawings can be edited and overlayed with new design information.
Intelligent one-lines, three-lines, schematics, panel, and wiring diagrams can also be created in the design process. These designs are integrated with the 3D model. Detailed designs such as protection and control schematics and wiring diagrams are created in the workflow, ensuring design quality and consistency.
Managing and Delivering Content
A 3D model must be able to produce the deliverable drawings required by the project. As such, new generation substation design applications must be able to automatically extract drawings for the general arrangement plan and elevations, foundation plan, grounding plan, control house layout, and other required deliverable documents. It must also be able to support a range of publishing options, including hardcopy and digital plots, Adobe PDF files, raster images and other formats. In addition, it is essential that the solution allow for Web- based publishing of the project drawings.
Technical content creation is also managed during the design process, and a consistent user interface is available from conceptual design through detailed design, construction, commissioning and operations.
The benefits of 3D design and modeling of substations include:
- Cost savings through design automation, reduction of construction problems and faster throughput of projects;
- Rapid evaluation of design alternatives to optimize design;
- Reduced time-to-market to meet customer demands and competitive pressures;
- 3D standards for advanced engineering, automated drawing and data extraction, and reusability of designs;
- Improved quality and reliability of design;
- Computer-aided visualization of the substation for site selection, permitting and community acceptance; and
- 3D visualization and walkthrough for construction, commissioning, operations and maintenance.
This is only the beginning. In the future, users may integrate engineering design and analysis with the 3D model, readily share model data with manufacturers, perform design reviews in 3D, provide intelligent models for construction and commissioning, and share information with contractors and other stakeholders in a secure manner across the Internet. In fact, many of these operations can be accomplished today.
Mike Lambert is the product manager for substation design at Bentley Systems Inc. He is responsible for developing utility design and engineering applications. He has more than 30 years of experience in electric utility and industrial plant engineering, as well as product management for CAD/CAM/CAE software for electrical design and engineering. Lambert received his B.S.E.E. and M.B.A. degrees from the University of Alabama. He is a member of the IEEE.