A few years ago, a sales-engineering team from a large multi-national architectural and engineering (A/E) firm visited Public Service Company of New Mexico (PNM; Albuquerque, New Mexico, U.S.) with a proposal to outsource PNM's entire engineering department. The firm met with a senior vice president and presented a package showing how it could reduce costs and respond faster than an internal engineering department. The executive listened and then asked how long it would take the A/E firm to design a typical distribution substation. The answer was about six months. PNM's engineering department was doing this same task in about eight hours and had reduced the cost by 25%. The A/E firm departed, and the engineering department continued meeting the engineering needs of PNM.

Standardization Saves Money

This efficiency was the result of three colleagues taking the time to develop a computer program to make their lives simpler. They called their program 3-Dimensional Design And Substation Layout or 3D-DASL (see “The Point and Click Distribution Substation,” T&D World, March 1999). This story is about how the three developed an automated design tool to produce a complete set of detailed construction drawings (plot plans, sections and elevations, along with grounding, conduit and foundation plans) for a distribution substation.

In the process, they realized that when you strip away all of the engineering jargon, there are only so many ways to arrange bus and equipment economically and efficiently. It was a process waiting to be standardized. They found that the cost to build the facility is reduced if it is repeatable. Equipment costs are reduced if the same equipment is purchased from the same supplier year after year. Spare parts inventory is reduced if all the equipment is the same. Maintenance of the facility is done faster if each station has the same equipment, and they are all alike.

But that is not the end of the story. As it turned out, it was only the beginning. The three were not content to rest on their laurels. They keep pushing the envelope, and the program continues to evolve as they ask each other, “What if we could…?” They knew the distribution substation was only the tip of the iceberg. They proved that 3D-DASL works great for a “new” distribution station. By automating the entire task, 3D-DASL does all the busy work. The repetitive tasks are programmed into menus allowing the engineer to point and click. The automated portion of the program can turn out the detailed construction drawings for a new distribution substation quickly, but what about adding to an “existing” distribution substation? What about a transmission station — could it too be automated? A transmission station is bigger with more equipment, but it consists of the same equipment and material as the distribution station. It also fits the criteria of a standardization process. Many questions had to be answered, but the challenge was there and the colleagues continued to “play” with 3D-DASL.

User-Friendly Process Spells Success

Much of the success of 3D-DASL came from its user-friendly menu system and the fact that it does not rely on a highly trained workforce of technicians or draftsmen. The engineer simply launches AutoCAD to access the program. AutoCAD's tool bar (menu across the top of the screen) has been modified to include a “3D-DASL” button. When selected, a pull-down menu appears. To produce the distribution substation drawings, the engineer selects “Distribution Substation” from the menu. He is then prompted by a series of dialogue boxes to specify the type of design (based on PNM's design philosophy). But what about adding functionality to work on an existing station? If the program becomes more complex to use, the engineers may not utilize it. The prime directive could not change. The engineers are not expected to be AutoCAD technicians nor are they expected to know 3-D drawing (in the X, Y and Z-axis) techniques. 3D-DASL had to remain a design tool to enhance the engineer's flexibility in manipulating station designs, not a drafting tool.

PNM Develops Search Engine Technology

The first problem encountered with 3D-DASL working with existing station drawings was the drawing itself. The majority of the drawings were paper or velum (hard copies). They had to be changed into a format the program could work with without requiring a lot of man-hours invested in the transformation. Timing is everything, and the 3D-DASL developers got lucky. Independent of the 3D-DASL developments, PNM decided something had to be done about the extremely large library of drawings maintained by the drafting department. Literally tens of thousands of drawings were on file in cabinets in the drafting department. They took up a large amount of valuable floor space and continued to grow each year.

A project initiated by PNM's Innovative Software Solutions department (ISS) scanned every drawing (transmission lines, substation, switching station, control and communications) into an electronic TIFF format in the PNM file system and stored them on a server. Having the drawings in the TIFF format was only part of the project. They had to have a user-friendly retrieval system as well. ISS researched the commercial search engine technology available, but found nothing that met PNM's needs. Once again, PNM developed its own software and called it “DrawBase.”

DrawBase was developed using the same technology driving today's popular Internet search engines. In a fraction of a second, a user can easily find any drawing in PNM's library. The drawing search can be initiated by discipline (controls, communications, station and line), drawing name, CAD file name, drawing number or station name. Once the drawing has been found, users may view the drawing from their browser, load a scalable file into AutoCAD, or print out a full or reduced size hard copy for markup and later reference. The user also has a choice of retrieving one drawing at a time or in a complete station drawing set. It has proven to be useful over the years; engineers no longer have to respond to a telephone request for information with “I'll call you back after I find the drawing in drafting.” They can look at the drawing right on their computer. Anyone with access to the PNM Intranet now has access to the entire drawing library.

The pieces of the puzzle were coming together. DrawBase made it possible to access any drawing in the PNM drawing library, and AutoCAD allowed these TIFF files to be scaled and manipulated. 3D-DASL had to be expanded with new routines to allow for easy placement on equipment anywhere on the drawing by the engineer. It also would be nice if the routine allowed the engineer to select the type of equipment (disconnect switch, breaker and transformer), the voltage level (115-kV, 138-kV, 230-kV and 345-kV), and single- or three-phase devices. Someone else asked for the ability to draw the bus at any height just by telling 3D-DASL the desired height. This brought another wish: to be able to tell 3D-DASL how high the bus support should be. The wish list grew, and the developers continued to find new solutions for each of the wish list tasks.

Dialogue Boxes Simplify Menu Selections

Dialogue boxes were developed to simplify the process and shorten the menu choices. Because the dialogue box worked so well in the automated selections, it was thought they would simplify single- and three-phase equipment choices as well. One example of a new dialogue box is found in the bus support column selection. When selected, a dialogue box pops up asking the engineer to select the voltage level, bus tubing size, height of bus and type of equipment (for example, insulator, surge arrester, instrument transformer or disconnect switch). Each voltage level has its defaults based on PNM's standard bus supports, but there is also the ability to define the height of the steel. If three-phase was selected, the phase spacing may also be defined. The voltage level selects the required station post insulator. A 3-D graphical representation of the selection is drawn “on-the-fly.” In other words, in all cases, a routine has been developed to draw what the designer selected.

Once all of the routines were added to the program, the developers had a system capable of dealing with the “existing” station. The existing drawing (now a TIFF file) is imported into 3D-DASL and placed on a unique layer. Using the TIFF image as a guide and a toolbox of handy routines from 3D-DASL, the designer can quickly trace any or all of the information to the appropriate layers. Once the existing information is transferred to the new drawing, the old file layer is turned off and frozen. The designer now has a new 3-D drawing to work from for the new addition. This process normally takes just a few hours to trace all of the old drawing's details to the new 3-D drawing.

Standardization of Process is Proven

The next challenge for the developers was the standardization of switching stations. Station dimensions, phasing and equipment placement were relatively easy to standardize, but critical issues with configurations were not. If the station starts life as a ring bus, it must be expandable to a breaker-and-a-half configuration. For a 115-kV station with two through six terminations, the configuration was pure ring bus, but at the seventh termination, the configuration will change to breaker and a half.

PNM's policy for 230 kV and 345 kV was a little different. The ring bus converts to breaker and a half configuration at four terminations. It was intended to automate these designs and add them to the 3D-DASL “pull-down” menu. Regrettably, before the coding could be completed, the concept of transmission switching station standardization was given an acid test. PNM was called on to design, procure and build the Taiban Mesa 345-kV switching station for the New Mexico Wind Energy Center (see “Wind Power,” T&D World, November 2003). The design philosophy had been developed, as had the 3D-DASL routines. This gave the team a tremendous head start on the project. As a result, the station went into service in a little over four months.

The Taiban Mesa switching station proved standardized station designs work. As a result, 3D-DASL automation continues forward. When completed, it will include 115-kV, 230-kV and 345-kV transmission switching stations. The developers completed standardized designs for all switching stations in the 115-kV and 345-kV voltage levels. The 230-kV station design is expected to be completed in 2005. Coding for the dialogue boxes has begun. After the implementation of the 115-kV station, the process will be modified for 345-kV switching stations. As each voltage level is completed, it will be added to the menu and PNM's engineers will access an automated process for all voltage-level switching stations.

Where Do We Go Next?

PNM applied for a patent for 3D-DASL. Hearings were held at the U.S. Patent Offices in Washington, D.C., earlier this year, and PNM was notified in October that it had been awarded the patent for 3D-DASL. From a simple idea to set limits on drawings has come a process that has changed the way PNM does business. 3D-DASL has reduced the time required to design distributions substations from more than 600 hours to less than 8 hours. Overall, PNM estimates a savings of approximately 25% for the average distribution substation. The challenge will be to realize the same type of time and cost savings with the switching stations. PNM feels this has verified the concept of standardization of process.

Gene Wolf, a contributing writer for T&D World, is principal engineer with Public Service Company of New Mexico, where he is responsible for the design and construction of EHV station facilities.
gwolf@pnm.com