Kansas City, Kansas, is home to a NASCAR racetrack, a professional soccer stadium, a water park, a new high school, and an outdoor shopping and entertainment district. Multiple highways connect in this one spot, attracting business owners and potential homeowners to settle near this area.
To meet the increasing power demand sparked by the surge in new construction, the Kansas City Board of Public Utilities (BPU) is constructing a new 161-kV transmission line and Wolcott distribution substation in Wyandotte County, Kansas.
The utility is partnering with Capital Electric Line Builders, Longfellow Drilling, and Asplundh Tree Expert Co. on the project, which will interconnect two 50-MVA substations located 8.5 miles apart. Barring any unforeseen stoppages, BPU and its contractors expect to wrap up the project in the second week of January 2014.
Staying on Schedule
The team began the project in spring 2013 with right-of-way clearing and mitigation issues. Foreman Kyle Baur, who has been with Asplundh since 1985, says the construction crews were working on a minimal right-of-way on the new construction for the 161-kV transmission line with an existing three-phase underbuild. To give the line crews more clearance, the vegetation management crews spent one warm, sunny September afternoon trimming a canopy of overgrown sycamore trees.
The crews not only faced challenges with overgrown vegetation but also with the wet weather. While the ground was moist, the workers did a lot of preliminary road and right-of-way work. This summer, the construction crew had a month of dry weather, which helped tremendously following the wet spring. During that time period, the field workforce was able to erect the poles, drill the foundations, and then come back through with the distribution poles and get them planted. While drilling the foundation for the poles, Longfellow Drilling encountered some unexpected issues with the underground utilities. While it slowed down construction, as it dried up, the workers were able to make up some lost time.
Overall, the linemen installed 74 steel transmission poles from TransAmerican Power Products Inc. (TAPP). These poles feature brackets for the hook ladders to enable linemen to use their linemen’s belts and harnesses to climb the steel poles and then tie off around the insulators.
To save time on the project, the linemen assembled all of the insulators on the top section of the pole and erected the completed structure rather than assembling them after the poles had already been set. By installing the insulators on the ground instead of up in the air, the linemen saved more than an hour per structure.
Other issues that the field workforce faced on the project involved the right-of-way. While the transmission line follows a road in Kansas City, it also cuts through an open meadow adjacent to farmland and homes. In order to have enough room for a new substation and the transmission line, BPU purchased 14 acres from a private landowner. While building the line through this cross-country section, BPU had to trim the trees in the right-of-way and focus on getting construction roads built wherever possible.
In this area, the right-of-way was untouched and undisturbed ground. In fact, the line even dips down through a natural spring and creek at the bottom of the valley. When designing the line, Burns & McDonnell, the engineer on the project, took into account the elevation changes. For example, the elevation drops about 80 ft from one of the poles down to the bottom of the creek, so the linemen did not set a pole in the lowest point of the valley.
To meet the environmental restrictions, the workers installed a huge culvert, covered it with gravel and put in a road to go through the bottom of the valley, where there is a natural spring. This kept the creek contained and flowing along its natural route while heavy equipment was being used in close proximity for the construction.
BPU and its contractors not only had to mitigate the creek issue, but they also had to trim the trees and make the road passable for the big pieces of heavy equipment. To transport the heavy vehicles and equipment down into the area, the linemen hauled it in with a bulldozer. Because they could only get limited equipment down in this area, the crew members hoisted or jacked the poles together on the ground and then stood them up as a whole pole rather than in three sections as was the case in other parts of the line.
When working in the cross-country section of the project, the linemen encountered varying terrain. For example, when they got down 12 ft to 14 ft, they hit rock. This forced the Longfellow Drilling crew to change the type of bit they were using on the track hoe and go down into the hole three or four times to reach the necessary diameter. As a result, it slowed down the drilling process considerably.
Another challenge was getting the concrete pumper down in the lower terrain since the workers couldn’t drive the concrete trucks right down to the foundations in some cases. To solve this problem, BPU brought in a pumper truck with a boom that would pump the concrete up the boom and into the foundations.
Overall, they installed 14 structures in this section that spanned about a half-mile to three-quarters of a mile. One of the structures was a three-way dead-end structure, and as such, it had a larger foundation of about 8 ft in diameter and roughly 46 ft deep. The linemen installed this structure to handle additional conductor from the east and out from the west. BPU will be installing another future substation to the north, and this larger pole is also where an additional new feeder will connect.
In addition to setting the steel transmission poles, the linemen also set wood distribution poles for BPU’s spacer cable underbuild. This part of the project will serve as an express back-up feed to a major water supply pumping facility and provide a feeder interconnect to the new Wolcott substation.
The linemen are installing 148 H-class distribution poles to handle the weight and associated bearings of the spacer cable. The spacer cable is 750 MCM, so it is fairly heavy. The spacer cable project is new to BPU, and by pulling the wires together on the spacer construction, it saves room on the pole and limits the right-of-way requirement.
Setting Steel Poles
As of September, Capital Electric had two steel structures left to set, and the linemen were focusing on stringing their rope rig from the substation to two of the remaining structures. One afternoon, the groundsmen were focusing on finishing the foundation for one of the steel structures.
Before they started this process, Longfellow Drilling Services drilled a hole and inserted an interior cage for the foundations, which were about 6 ft in diameter and 24 ft deep. Capital Electric then returned to the site to set the base onto the foundation, and the groundsmen ran the nuts down to where they needed to be and then secured them into position.
The next step for the linemen was to stack the three sections of the pole piece by piece on top of the foundation. The journeymen linemen prepared to lift the three sections of the steel pole off of the truck with a crane, hoist them up and then gently set them into place.
To ensure that the three sections would slide easily together, one of the linemen sprayed a mixture of soap and water on the bottom of the pole section prior to installation. A crane operator then hoisted the section in the air while two linemen in a basket attached to another crane helped to position the pole sections so they would fit together.
Ben Draper, general foreman for Capital Electric Line Builders, was supervising his crew members as they were setting a 130-ft-tall steel structure. Because of the height of the pole, the linemen had to bring out the pole in three separate pieces and then set it piece by piece using a 120-ft, 30-ton crane and a 130-ft, 38-ton crane.
Further down the road, the linemen also installed shorter 60-ft steel transmission poles that were direct buried and had no foundation. The reason why they went with steel rather than wood poles in this residential area was to make the line look more uniform as it approached the north edge of the Legends shopping district.
By working together, the linemen were able to construct the transmission line to feed the new substation, and in the process, expand BPU’s capacity and allow the utility to meet the growing demand for power in western Kansas City.
Jeremy Ash ([email protected]) is the superintendent of electric operations for the Kansas City Board of Public Utilities in Kansas City, Kansas. He has been with BPU for 14 years and is responsible for the oversight of overhead transmission and distribution construction.
Asplundh Tree Expert Co.| www.asplundh.com
Burns & McDonnell | www.burnsmcd.com
Capital Electric Line Builders | www.capitalelectric.com
Kansas City Board of Public Utilities | www.bpu.com
Longfellow Drilling Services | www.quanta.com
TransAmerican Power Products Inc.| www.tappinc.com