Construction activities & Support2

 

CASE 1: Conductor with signs of stain or corrosion was installed (TX)

Issue: The contractor noticed some type of surface defect on the 1272kcmil ACSR Bittern conductor. Initially the subcontractor didn't say anything to anybody and went ahead to install the conductor. TLine FW345-TX

Solution: Southwire was contacted and confirmed a case of water staining. "When conductor reels are stored outdoors, water can accumulate on the conductor on the underside of the reel. If the water contains chemicals from the surrounded atmosphere, a black water stain can appear on the conductor. Water stains are a cosmetic issue; they have no adverse effect on the performance or service life of the conductor. In most environments, the conductor will darken in the first few months after the line is energized, and the stain will no longer be noticeable. Aluminum Association Technical Bulletin TR3, "Guidelines for Minimizing Water Staining of Aluminum" discusses this issue in detail and contains advice for avoiding water staining." 

In summary, while aesthetically displeasing, the stains will have no adverse effect on the conductor.

                     Amarillo-TX

CASE 2: Jumper arm installed incorrectly on the wrong side. (TX)

Issue: The contractor installed the steel jumper arms on the wrong side of the 345kV steel pole.

Review: It was noted as a design-manufacture error by the vendor, not captured during their QA/QC nor the consultant review/approval.

Solution:  Part of the external thru plate was cut and installed/welded on the opposite, right side of the pole. Schedule was a factor to resolve the issue quickly.

a.)Cut the thru plates off on the outside, 4.5" min from the edge. b.)Trim the cut part if necessary to the proper length, and double bevel the weld edges 45 degrees. c.)Remove the galvanizing coating from the butt ends of the thru plates. d.)Fit up the cut part to the thru plate butt ends, the bolt hole MUST be vertical inline and 3" from the shaft face. e.)After fitting up. weld up the cut parts to the thru plate butt ends. Clean the welded areas. f.)Touch up the welded areas with zinc rich paint per ASTM A780 requirement.

CASE 3: 345kV Steel Pole damaged while stringing conductors. (CO)

Issue: The top pole section, where the bracket attaches and is welded, was damaged/dented during the conductors stringing.

Solution: After a quick review with the manufacturer, the top section of the pole was decided to be replaced. Cost: $8,519+freight (Aug.2023)

 

CASE 4: Galloping occurrence on the new 345kV TLine (CO)

Issue: Outage occurred due to galloping effects on a new TLine a couple of months after energizing(Dec. 2023). Airflow Spoilers were already installed to avoid galloping on all East-West sections of the TLine where galloping was noted on another close in-service TLine.

Solution: It's under investigation. Possibly the whole line should have been considered to have airflow spoilers, not only the East-West sections.

Airflow spoilers installation (08.18.2023)

Construction activities & Support1

CASE 1: Conductor damaged during installation:

2x1033.5 kcmil, 54/7, ACSS MA2 Curlew, 35,000Lbs RBS

New 20miles, 345kV Tline, 2050 MVA, 140Ft ROW, IN

Solution: 

1.)Armor Rods=No 

2.)Sleeve repair=Yes, but not immediately available during construction

3.)Splice=Yes, available. Installed.

Result:

CASE 2: Arm deflection:

Issue: The 345kV arm installed on ground didn't show a 2deg. rise design deflection, it was 2" less than designed.

After the review with the manufacturer it was clear 1.) The arm was not manufactured following the design or 2.) Installation was not done properly. It, most probably, was 1.

Solution: After the analysis with the manufacturer it was shown that the missing deflection would Not affect the structure capability itself. The installed arm downward deflection was Not noticeable.

CASE 3: Conductor damaged during installation:

Issue: One of the lineman nicked the wire while hanging jerk ropes. 3 strands were broken and about 5 other were nicked up.

Solution: Armor rods were installed following the PLP repair manual table.

CASE 4: Foundation construction, water presence (345kV Weathered Steel pole, double circuit, double bundle conductor)

Issue: Unexpected water was encountered while drilling the foundation for a 345kV Steel Pole installation.

Solution: Drill an oversized shaft with the use of temporary casing and drilling under water with slurry products. The pole base is 7'-9" in diameter. Contractor looked to drill a 13' diameter shaft down to 45'. The contractor poured concrete via tremie method to fill the shaft. Once the concrete has set-up, contractor drilled drilled through the concrete with a 9' tool to give the pole base 6" of clearance all the way around. Contractor drilled down to 40' leaving at a 5' of concrete below the pole base. Contractor then set the pole base maintaining plumb and twist and backfill with stone and concrete.

This new procedure took place at a new location. 

Notes: -After the review of the geotech report and foundation design, it was determined that the plug within the CMP and lack of concrete backfill around the CMP caused the CMP with plug to float. The new procedure for installation focused to ensure the backfill around the CMP is complete and set prior to pole installation.

-For the hole and CMP that remained at the existing drilled foundation, the contractor was ordered to review if CMP can be removed and hole salvaged. The concrete cured to the CMP  removal is challenging. Contractor was asked to review if there are appropriate means & methods to remove concrete from the CMP, clean out the hole and reset the plug and structure. On the other hand for the hole abandoning option contractor was requested to backfill hole to ensure all voids are filled, including the floated CMP.