Permanent Solutions to Temporary Loads: An Alternate Approach to Electrical System Design for Short Term and Mobile Industrial Loading Presented by: Eli ImMasche, P.E. and Aaron Potts, P.E.

2016 IEEE Rural Electric Power Conference Westminster, Colorado Monday, May 16, 2016

Background Oil and Gas Company required infrastructure to develop large field. –Field covers 100 square miles. –Field straddled two utility service areas, 69kV and 34.5kV. –Each square mile could require 7MVA of transformer capacity. Open air substation. –One required every few sections. –Loads would last several years. –Result in large investment of equipment and capital.

Potential Solution Mobile Transformer. –Allows for mobile and temporary loading. –Special training required. –Road registration required. –Maintenance of trailer can be an issue.

Potential Solution Skid Mounted Transformer. –Utilized in mining. –Maintenance not as much of an issue. –NESC clearances not designed to. –Special training required.

New Idea Required Design required that would minimize or eliminate special training. Eliminate as much special equipment as possible. Must be mobile but durable. –Skids are mobile and durable. –Need to be under 16 feet wide to ship with oversized permit. –Under 14 feet wide preferable. Must meet RUS clearances. –For 69kV, largest clearance would be for vertical break switch. –5’-0” phase-to-phase, so 10’-0” outside to outside. Mounting a substation on a skid would be feasible.

Skid Mounted Substation Combines safety of open air substation with mobility of mobile transformer. –No special electrical training required. –No degradation of a trailer. –Highly portable. –Skid Mounted Substation was created.

High Side Skid 7MVA transformer. –69kV or 34.5kv high side voltage. –12.47kV low side voltage. High side H-frame. –69kV fuses for protection. –group operated switch for isolation. –Normally about 27 feet tall. –Too tall for road transportation. –To allow for transportation, H-frame was hinged. –Reduced shipping height to about 13 feet.

Low Side Skid Regulator bank. Cooper Nova recloser. Group operated isolation switches. Control enclosure for SCADA if desired by utility. Steel structures also hinged.

Sub-Transmission & Distribution System 96 Sections (Square Miles) NORTH REA TERRITORY SOUTH REA TERRITORY 115kV Source 115/69kV Substation 115/34.5kV Substation 34.5kV Circuits w/ 12.5kV Underbuild 69kV Circuits w/ 12.5kV Underbuild

Sub-Transmission & Distribution System (Cont.)

System Characteristics RUS single-pole wood structures. Typical span length of 250 to 300 feet. Overhead and underground service drops. Service drop loads of 500 to 3000kVA per well pad.

Initial Build-Out 34.5/12.5kV Lines. –14 circuit miles of line. –40 ft. wide Right-of-Way. –8 skid substation locations. –3 skid substations installed. 69/12.5kV Lines. –16 circuit miles of line. –80 ft. wide Right-of-Way. –10 skid substation locations. –3 skid substations installed.

Challenges Avoid conflicts with parallel and crossing oil & gas infrastructure. Production field is co-located with a United States Air Force Missile Squadron’s alert and launch facilities. National Grassland is interspersed with private lands throughout the production field. Daily coordination with oil & gas company’s pipeline construction personnel.

Skid Substation Sites Relatively level location to minimize grading. Good access for hauling skid substation to site.

Skid Substation Transition Structure Tangent construction. Minimal additional cost vs. typical tangent structure. Provides needed horizontal separation between 69/34.5kV and 12.5kV underbuild.

Skid Substation Installation Site grading and ground grid. Skid substation craned or skidded into position. Skid substation assembled. Flying tap pole installed. Fenced and rocked.

Skid Substation Connection Skid substation oriented 15 degrees from powerline centerline. High-side aligns with flying tap pole. Low-side directly below underbuild.

Complete Skid Substation

Questions??? Eli ImMasche, P.E. (970) Aaron Potts, P.E. (970) ESC engineering, Inc John F. Kennedy Parkway Fort Collins, CO (970) Now Open in Durango, CO 1315 Main Avenue, Suite 326 (970)