Wednesday, December 13, 2017
Greenfield, Brownfield Substation Projects Reap Design, Collaboration, and Construction Benefits from BIM and Reality Modeling
Whether designing greenfield substation projects from the ground up or performing brownfield design associated with existing substation infrastructure, intelligent 3D substation design employing BIM processes and reality modeling demonstrates cost and time saving benefits.
In a greenfield project in Cambodia, PESTECH undertook a project for Diamond Power Limited for the conceptual design through commissioning of the 230-kilovolt Kratie and Kampong Cham Substation and Transmission System. The project will support the growing population and tourism industry. The Kratie 230/22-kilovolt substation will connect with the Sesan hydropower plant, which is under construction in the upper Mekong area, and also serve as a major collection center of power from several mini hydropower plants, connecting to the national power grid of Cambodia.
Visualization of the 3D substation design was essential to prepare and plan work before and during construction. The site was located far from the town within forest and hilly roads and visualization of the design with accurate dimensions was a significant challenge, which was successfully overcome using Bentley Substation and Bentley Navigator. ProjectWise was used for collaboration across departments on-site and offsite including procurement, management, engineering, and construction. The project is expected to be completed in November 2017 and PESTECH will also be responsible for operating the power transmission system for a concession period of 25 years.
The design of past projects was done manually, via hand-drawn and manual calculation of components and third-party CAD software. This approach was prone to human error, time consuming, and resulted in inconsistent quality. PESTECH’s engineering team reported many benefits of Bentley Substation from the unified design environment facilitating cross-discipline collaboration, automated design drawing and reports, enforcement of engineering standards, and more. These included cost savings in procurement, reduction in errors, and substantial time savings. A detailed analysis comparing the use of Bentley applications with previous methods estimated time savings of up to 70 percent were achieved.
In contrast, approximately 95 percent of Pacific Gas & Electric’s (PG&E) annual USD 1 billion substation budget is spent on existing brownfield substations. Since 2016, PG&E has been pioneering the use of a combination of aerial equipment such as man lifts, unmanned aerial vehicles (UAVs), and on-ground photo equipment to capture images of existing substations. Bentley’s ContextCapture is used to process these images and produce accurate 3D reality meshes, which can be referenced into Bentley Substation to complete the entire substation design in 3D. ContextCapture models allow effective collaboration between the Transmission Line, Land Planning and Zoning, and the Electrical and Civil Substation Engineering departments. ProjectWise is used to manage the models and facilitate collaboration. With up-to-date 3D models, all stakeholders can clearly see the impact of each department on the project, avoiding costly conflicts in the field and allowing for more streamlined, effective, and sustainable long-term planning.
For community and government relations, this method can be used to capture and retain historical infrastructure in 3D before new construction takes place. In areas where thick ballistic walls for security are required by the Federal Energy Regulatory Commission’s (FERC), realistic renderings of the existing substation and new security walls in 3D helps to gain community acceptance. 3D models generated by ContextCapture can also be utilized as a mesh to generate quick and low-cost digital terrain models and enables PG&E to identify and categorize existing substation assets for condition-based maintenance substation asset inventories.
PG&E expects to reduce cost spent on recreating existing substation equipment in 3D by 50 percent, a reduction from 120 hours to less than 60 hours on average. Improving captured 3D model’s accuracy to within inches will eliminate field measurements on cleared and energized equipment. PG&E also expects a 50 percent reduction of substation personnel travels to and from substation facilities.
Ralph Hansen, construction supervisor, PG&E, said, “Having a complete 3D model at the time of constructability review allows us to measure electrical and physical clearance in real time, which helps eliminate costly conflicts during the construction phases. With today’s increasing substation complexity and decreasing substation footprint, having a 3D model is a must.”
The South Street 115/11.5/23-kilovolt Indoor Substation project executed by TRC for National Grid involved rebuilding South Street Substation in Providence, Rhode Island, converting the existing three 115-kilovolt overhead line supply circuits to underground cable circuits, and re-routing the existing 23- and 11.5-kilovolt underground feeder getaway facilities. To complete the project on time and on budget required TRC to integrate existing conditions to the new construction while the substation remained in operation. This project was also in a highly visible and congested area, which caused concern over the aesthetics of the site and building.
The project had a very complicated building design and required incorporating a large number of subcontractor files in third-party formats to a single master design model for cross-discipline checking. These files were placed in ProjectWise and provided an indisputable record of what was received from subcontractors. Bentley Substation was used to integrate these different formats into the Bentley Substation models by TRC staff in design centers across the country. As a result, TRC identified issues before construction or fabrication that would have led to delays at the site and cost overruns. Bentley Substation was used to do full 3D client walkthroughs for interior and exterior design reviews and the 3D models were also used in the renderings for the planning board and for public comment.
Jason Poissonnier, TRC ProjectWise administrator, said, “Bentley Substation along with ProjectWise was instrumental in successfully completing the South Street project, which was in a congested, highly visible area. TRC utilized resources from several offices who collaborated on over 2,000 CAD files as well as Excel, Word, PowerPoint, Outlook, PDF, TIFF, and other files. The ability to incorporate different types of design files from subcontractors into the 3D model made the design reviews truly all-encompassing and resulted in identifying many areas that needed redesign, thereby avoiding costly changes later during construction.”