When it comes to the design and maintenance of electric utility substations, functionality often wins out over aesthetics. Extensive landscaping often works well in rural areas, but in rapidly expanding urban environments, electric utilities often face stringent local laws as well as tight spaces. Westar Energy has met this challenge head on in its service territory, which encompasses both urban and rural areas in eastern Kansas.

Standard fence material for substations is chain link, which is economical, secure and works well in rural locations and small towns. However, most of the larger cities and more developed counties now require more extensive visual screening around substations. In some areas, Westar has achieved this visual screening through landscaping, but local regulations in other areas are so restrictive that the utility must build a solid fence.

Researching Alternatives

Throughout the 1970s and 1980s, Westar used decorative masonry block walls; however, over time as the walls age, they haven't lasted as long as expected. Several of the walls developed serious structural problems after about 20 years and required replacement. Although the masonry walls are a unitized rigid product, the material is very porous and absorbs water. This causes cracking in the walls and joints, making the wall unrecoverable and demanding a considerable cost for installation and repair. For that reason, Westar searched for another option for the solid wall enclosure.

In the mid to late 1990s, a senior engineer for Westar began searching for better alternatives to the masonry blocks. The first alternative was a cast-in-place concrete wall similar to an aboveground basement wall. Westar installed the cast-in-place wall around a few of Westar's substations in the Wichita, Kansas, area. The company, however, wasn't completely satisfied with the finished product. While the decorative forms made an attractive wall, they were expensive and difficult to repair or move.

Westar then opted to partner with Wolf Construction, which performs a lot of Westar's substation earthwork and concrete work. Dave Gary, the president of the company, has been working with Westar on its substation projects since 1981. He started out building the masonry fences to address the zoning requirements for substation construction. Westar challenged him to find a product that would meet zoning requirements without needing much maintenance.

In addition to the cast-in-place system that had been researched, wooden fencing systems had been considered, but the nature of the environment prohibited that option. Combustibles around the volatile equipment within a substation would present major problems if faults were to occur.

Discovering a New Product

With two alternatives eliminated, another option was to install a steel panel or chain link fence with privacy slats. Maintenance issues, however, caused Westar to research precast concrete systems.

In 2005, Gary discovered Verti-Crete, LLC. Based in Bluffdale, Utah, the Verti-Crete System has only been around since 1999. Precast concrete was a proven durable material that Wolf Construction was able to cast in a factory-like setting. This allowed control of the elements used to cast the concrete, such as the flashcrete content and the microfiber content that prevents micro-cracks in the concrete.

Gary then founded Stone-Cast, LLC, an exclusive licensee of the Verti-Crete system and a subdivision of Wolf Construction. Stone-Cast builds an industrial version of precast panel walls. This alternative, although expensive initially, has a life expectancy of about 50 years compared with the 25-year life expectancy of the chain link or masonry block fences. Although the initial price is relatively high, the lifetime cost is actually less than other options because of the longevity of the panels and the fact that they are virtually maintenance-free.

The Ease of Construction

When building a wall, Stone-Cast pours the concrete columns and panels at its shop ahead of time. At the job site, the workers then pour the concrete footings for the columns. They then slide the panels into vertical slots on the sides of the columns. Once the footings are set, the columns and panels can be assembled quickly at the job site whenever weather and scheduling allow.

The fence stands about 9 ft high, with columns spaced at 13 ft, 2 inches. The panels are 6 inches thick, and the foundations are 2-ft-diameter piers, with depth varying with soil conditions. The columns are 20 inches square, which serve as a key weight joint for the panels. This is a loose joint that allows for expansion and contraction in various weather conditions.

Using decorative forms, Stone-Cast constructs the columns and panels so that the walls appear to be made of limestone. The panels are cast on both sides and, if needed, can be reversed in the case of minor damage to the concrete. In addition, the concrete walls can be stained in a variety of colors to look more like stone. Companies can select from 25 colors, but Westar and Stone-Cast worked together to create a Westar-exclusive color called Stone-Cast Beige. If present, graffiti is easily corrected by restaining the wall.

Advantages and Added Security

The Verti-Crete fencing system offers several advantages for use with substations. Unlike chain link fence, which requires grounding built into it, the precast fence isn't conductive, therefore, it doesn't require this grounding, so Westar doesn't need to worry about the fence becoming energized. While gates are installed in the fences to provide access to the substation equipment, Westar can remove the fence panels to provide additional equipment access with a better than 11-ft clearance between the columns. In the case of expansion, the panels can be removed and reused once expansion is complete. If Westar needs to add a bay to a substation, Wolf Construction can remove the walls to accommodate it.

Stone-Cast worked with Westar to accommodate an optimal security system for the substation fences. The 6-inch panels contribute to the security of the fence. Due to the weight and thickness of the panels, they cannot be penetrated or lifted without special equipment. This advantage keeps vandals from harming the substation or themselves, and keeps out any unwanted vermin. In addition, these solid walls offer protection from windblown debris, gunshots, and other hazards. Westar has had problems with damage at substations due to vandals shooting the transformers through a chain link fence. With the solid walls, a high-powered rifle cannot penetrate and cause damage.

Where allowed, some of the walls around the substations include alternating sections of the Verti-Crete walls and coated chain link. These hybrid fences usually are enhanced by additional landscaping. At the same time, they enable police to patrol the equipment easily. In addition, Stone-Cast can pour 6-ft walls, which Westar has used to conceal some of its propane tanks that have been previously subject to vandalism.

Sound attenuation is another advantage that benefits the urban areas. At one substation in the southern part of Westar's territory, decibel readings taken before and after the installation of the fence showed that it had actually reduced levels by 20 to 30 decibels.

Westar installed its first concrete wall around a 138-kV substation located at the south edge of Wichita, Kansas. Due to the success of the concrete wall at this substation, Westar has installed the fences around more than 10 of its substations. By partnering with Verti-Crete, the utility was able to not only balance beauty with functionality, but also safeguard its substations both now and in the future.

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Reba Liggett (reba.liggett@westarenergy.com) is an electrical engineering intern in Westar Energy's substation engineering division.

Cindy Risch (cindy.risch@westarenergy.com) is a senior engineer in the substation engineering division of Westar Energy.

Companies mentioned:

Verti-Crete, LLC www.verti-crete.com

Westar Energy www.westarenergy.com

Wolf Construction www.wolfconstruction.net