PG&E Streamlines 3-D Design and Modeling of Brownfield Substations With Advanced Image Capture and Latest Software Applications
By Cyndi Smith, Bentley Systems Inc.
San Francisco-based Pacific Gas & Electric (PG&E) is one of the largest combined natural gas and electric energy companies in the U.S. The investor-owned electric utility provides energy services to approximately 16 million people throughout a 70,000-square-mile service area in northern and central California. As a subsidiary of PG&E Corp., PG&E is part of California’s massive electricity generation system, which produces more than 296,000 gigawatt hours each year.
PG&E has experienced near constant growth in demand for energy recently. The number of California households has nearly doubled from 6.5 million in 1970 to 12.5 million today. While the number of consumers has grown, the dramatic way in which consumers use energy and electronics has made the biggest impact on PG&E’s grid operations. Keeping pace with changing demand patterns and a changing generation mix, which now includes intermittent renewable energy, is a significant challenge. PG&E’s grid operations are especially affected by the addition of residential customer-owned solar photovoltaic generation.
The traditional electricity grid has become ill-suited for resourcefully managing higher demand and the two-way flow of electricity. PG&E is just one of several utilities nationwide pushing to modernize the electric grid to make it more efficient, reliable, and responsive to consumer needs. Much of that modernization begins in its substations.
The utility owns and operates more than 1,100 transmission and distribution substations, almost 107,000 miles of distribution lines, and more than 18,000 miles of interconnected transmission lines, spanning two-thirds of California. The 140 employees who comprise the substation engineering department struggle to keep up with the volume of projects because of the push to modernize the grid. The group handles about 280 substation projects each year, including expansions, upgrades and retrofits, and has an annual budget of nearly $1 billion, Nam Trinh, a senior substation engineer at PG&E, said during a presentation at the 2017 Bentley Year in Infrastructure Conference, where PG&E was a finalist for a “Be Inspired Award.”
“Most of the substation work (about 95 percent) is at brownfield sites and we contract out about 65 percent of the engineering and design work to 16 different vendors,” Trinh said.
Substation Retrofit Challenges
Most of the existing infrastructure at the brownfield substation projects are documented by 2-D drawings. PG&E previously converted 2-D drawings to 3-D models for retrofit projects, but the process was time-consuming, and the results were often less than desirable. The laborious process started with the engineers taking the existing 2-D drawings of the facilities and filling in information gaps with field measurements. After about 120 hours of manual effort, the resulting models were frequently inaccurate due to errors in the legacy documentation and because the engineers were unable to go on site to measure energized equipment.
Several years earlier, PG&E had successfully implemented an application called Bentley Substation for 3-D design and modeling of new greenfield substations. The BIM solution switched the focus from 2-D drafting and design to 3-D design and modeling. The software reduced project design time by 40 percent and saved an estimated $5.7 million across approximately 120 substation projects each year. PG&E’s substation engineering department was searching for a method to turn existing brownfield substation infrastructure to 3-D models that it could design in conjunction with new 3-D designs on substation retrofitting projects.
PG&E’s substation engineering department, therefore, looked to Bentley for a solution for its brownfield substation projects. The substation engineering department replaced its laborious, imprecise conversion process with reality modeling using Bentley’s ContextCapture application. This new solution shortened model production time by one third. The highly accurate reality meshes are integrated into the substation platform for intelligent 3-D design of upgrades, then shared among design teams through ProjectWise, which is used as the central repository. This sharing feature is especially important because PG&E uses numerous vendors to help with its design work.
Automating 3-D Model Creation
ContextCapture incorporates advanced image capture and processing technology to create engineering-ready reality meshes from high-resolution photography and laser-scan point clouds. The application provides context for new design, construction and operations by modeling existing conditions.
To capture the imagery of its brownfield substations, PG&E deploys a combination of photographic techniques. “We used smart phones, sometimes with selfie sticks, to collect digital photos,” Trinh said. “And, if the substation was not energized, we used cameras attached to unmanned aerial vehicles (UAVs).” In some instances, employees used man lifts or bucket trucks to capture images, according to Trinh.
The application automatically identifies the relative position and orientation of each photo, reconstructs the images in 3-D, and maps the appropriate textures. The software produces a reality mesh that is then referenced into Bentley Substation. This allows engineers to complete the entire substation retrofit design using intelligent 3-D models that unite electrical and physical design.
Model creation takes less than 40 resource hours, including 16 resource hours for photo capture, 36 hours for automatic processing (no personnel required) and 16 resource hours for retouching.
The new solution eliminates the need for someone to draw all the different 3-D views and it reduces errors and revisions. In addition, PG&E can merge its engineering, procurement and construction 2-D drawings with the photos in ContextCapture.
One Source of Truth
PG&E’s substation engineering department manages project information with ProjectWise, enabling the electrical and civil design teams to seamlessly share the 3-D models and other data. By assigning geo-coordinates to the substation models, facility information can be incorporated into the utility’s geographic information system and be accessible to other departments and disciplines.
The three applications together provide one source of truth in a centralized location. The common data environment improves the accuracy and mobility of design and construction documents and reduces the risk of redesign and rework. Having information and deliverables available on demand improves project performance and accelerates project delivery. These benefits have been instrumental in PG&E’s ability to stay on track with the number of projects scheduled.
Essential Time and Cost Savings
PG&E’s substation engineering department was searching for a method to turn existing brownfield substation infrastructure to 3-D models that it could design in conjunction with new 3-D designs on substation retrofitting projects. With advances in image capture and processing, PG&E can now implement 3-D design more efficiently on existing brownfield projects at significant cost and time savings.
The 3-D models allow effective collaboration between transmission line, land planning/zoning and electrical/civil substation engineering departments. By having up-to-date 3-D reality models, all stakeholders can clearly see the impact of each department on the project. This allows them to avoid costly conflicts in the field and use more streamlined, effective and long-term sustainable planning.
PG&E expects to reduce 3-D modeling costs by 50 percent using reality modeling instead of manually converting 2-D drawings. The new process takes significantly less time to recreate an existing substation as a 3-D model, compared to the previous manual method of creating a 3-D model from 2-D drawings. The automatically generated reality meshes are accurate within inches. The accurate models also eliminate the need to take field measurements. As a result, personnel travel to and from the substation facilities has been cut in half.
“Having a complete 3-D model at the time of constructability review allows us to measure electrical and physical clearance in real time, which helps eliminate costly conflicts during construction phases,” Ralph Hansen, construction supervisor and Modoc Odom substation foreman at PG&E, said. “With today’s increasing substation complexity and decreasing substation footprint, having a 3-D model is a must.”
In addition, PG&E uses the software for tasks beyond the scope of modeling existing substations. The applications can be used to generate a reality mesh of the terrain, producing a quick and low-cost digital terrain model without a full land survey.
“We were able to perform volume calculation without using time and money to hire a surveyor,” Trihn said. “The civil engineers love it.”
The solution also can process images of substation assets that can be categorized, inventoried and used to plan condition-based maintenance.
Beyond the time and cost savings, reality meshes have been powerful communication tools that helps stakeholders outside of PG&E visualize projects. PG&E works collaboratively with surrounding communities to ensure that its facilities are safe, secure, environmentally responsible and compatible with current and future development in the area. Up-to-date reality meshes allow stakeholders to clearly see the impact of projects. These real-time updates help to avoid costly conflicts and changes in the field and they support long-term, sustainable planning.
In compliance matters, reality meshes provide realistic renderings of planned upgrades for existing substations and other facilities. Illustrating the visual impact of a new security wall, for example, helps gain community acceptance of features required by the Federal Energy Regulatory Commission. PG&E has found creative ways to maximize the value of the reality modeling software.
Trihn also mentioned another unique way the utility can use Context Capture. Occasionally, one of the utility’s “vintage” substations cannot be updated and must be replaced. In such cases, Trihn said the software solution is used to obtain photos of old substations for the historical society before the substations are destroyed.
Cyndi Smith is a senior industry marketing director for Bentley Systems’ utilities, water and communications industries. In her 16 years at Bentley, Smith has also led Bentley’s product marketing team and the global utilities solutions strategy as solution executive. She has an extensive background in the development, implementation and marketing of solutions for infrastructure in the communications, defense, oil and gas, and utilities industries.