APS Tempe Town Lake 230 kV OH/UG Conversion Project(The Rio Salado Project Phase II)

By:Ted Nishioka

Introduction

• Our customer, the City of Tempe, requested a conversion of overhead transmission lines to underground near Rio Salado Parkway Road and Farmer Ave alignment to Priest Rd.

• The City of Tempe needed these overhead lines relocated to construct their proposed Performing Arts Building near the Tempe Town Lake.

• Two-230 kV and one-69 kV overhead lines had to be relocated within the area. One spare 230 kV trench was included in this conversion.

Tempe Performing Arts Building

Project Management

• APS managed the engineering design and installation of the 230 kV underground lines.

• Klondyke, Inc. was the APS trench and conduit installation contractor.

• Pirelli Power Cables and Systems North America provided the electrical materials and installation.

230 kV Installation Route• The phase II 230 kV OH/UG lines conversion site begins

at the existing pull through manholes located at the Farmer Ave alignment and Rio Salado Parkway Rd., and transitions on the west side of Priest Rd. for a trench distance of approximately 6120 ft.

• Four parallel trenches were installed along this route for the following circuits.

1 ) Ocotillo to Lincoln St 230 kV circuit.2 ) Ocotillo to Kyrene 230 kV circuit.3 ) One spare 230 kV trench.4 ) Tempe to Jackson St 69 kV circuit.

230 kV Installation Route

•The phase II 230 kV circuits and trench ties into and extends each of the phase I 230 kV circuits and trench from the west pull through manholes.

•The existing Ocotillo to Lincoln St. and the Ocotillo to Kyrene 230 kV circuits from phase I were energized approximately 3 years ago, and the installation length for each circuit was approximately 4,000 circuit ft.

Fig No.1Rio Salado UG Transmission Line Route Phase I

Fig No.2Rio Salado UG Transmission Line Route Phase II

230 kV Trench Design

• 6”PVC conduit with 10”separation at depth of 48” to top of conduit.

• Concrete encased.• Select backfill used to

backfill trench to grade.• Two 24’ L by 10.5’ W

by 8’ H manholes per 230 kV circuit.

New Pavement Section

Select Backfill

4/0 Copper Conductor

Concrete Encasement

6” PVC Conduit (Typ.)

230 kV Trench Installation

• The trenching began on July 15, 2002 and was completed in the first week of October.

• The parallel trench separation was kept at 10 ft between trench centerlines.

• West of Hardy, landfill material was sporadically encountered for a distance of 600 ft.

• Hydro Geo Chem, Inc. in Tucson, Arizona provided information on methane abatement.

Fig No.2Rio Salado UG Transmission Line Route Phase II

230 kV Cable Installation

• Cable installation began on November 12, 2002.• The cable is a 230 kV 2000 kcmil copper

conductor, 945 mil wall XLPE cable.• Metallic sheath is 12 mil aluminum foil laminate.• The extruded semiconducting polyethylene Jacket

is a minimum 110 mil thickness.• Cable was pulled from the west end at the steel

transition poles to the first manholes. There were three circuit pulls at approximately 2000 ft each per line segment.

Cable Accessories• Requested Pirelli to supply the 230 kV joints and

terminations.• The 230 kV terminations were composite housing

(non-porcelain).• The height of the terminations is approximately

8.7 ft with a weight of 800 lbs. (including fluid).• The BIL rating is 1050 kV.• The 230 kV splice is a one piece premolded click-

fit joint.• The complete splice is approximately 5.25 ft long

and weighs about 154 lbs.

Date of Energization

• The Ocotillo - Lincoln Street 230 kV line was energized on January 21, 2003.

• The Ocotillo - Kyrene 230 kV line was energized on March 7, 2003.