Subsurface Utility Engineering & Asset Management. American Council of Engineering Companies/Maryland

Transcription

1 PHI s Underground Use of SUE in Transmission Design Process Subsurface Utility Engineering & Asset Management American Council of Engineering Companies/Maryland Presented by: Pepco Underground Transmission March 28,

2 Agenda Background About Pepco Holdings Pepco holdings Quick Facts PHI UG Transmission Design Process (Civil) UG Transmission Design Engineering Cost SUE Benefits / Challenges UG Electric Lines UG Electric Lines Construct Working In Close Proximity To Pepco Underground Facilities PHI UG Transmission Engineering Contact Q & A 2

3 About Pepco Holdings Approximately 2 million customers in Delaware, the District of Columbia, Maryland and New Jersey Atlantic City Electric, Delmarva Power and Pepco provide regulated electricity service Delmarva Power also provides natural gas service 3

4 Pepco Holdings Quick Facts Service territory: 8,340 square miles Customers served Atlantic City Electric: 547,000 electric Delmarva Power: 515,000 electric 130,000 natural gas Pepco: 842,000 electric Total population served: 5.4 million PHI Service Territory As of 2/19/16 4

5 PHI UG Transmission Design Process (Civil) Underground Transmission Design Guide Formally Issued in June 2016 Project Steps: Initiate Based on system need a concept is created Route Analysis o Level D survey for all possible routes o Level B survey in and around substations to ensure feasibility of approaching subs o Preferred route selected based on Route Matrix 30% Design Conduct Site Topography and Level B Survey Design Horizontal Alignment 60% Design Conduct Level A survey Complete Soil Borings & Geotech report Design Vertical Alignment 90% Design Complete Design details Obtain Applicable Permits Finalize design Issue for Construction Complete SOW for bid and award Example of PHI Design Checklist Checklists created to verify all information is provided during the each step of the design Complete Design Review at 30%, 60%, 90% and IFC stages In-field Constructability Review completed at 30%, 60% and as needed 5

6 PHI UG Transmission Design Process (Civil) 30% Design Topographic survey completed Level B Survey completed Horizontal alignment designed Constructability and Design reviews completed Example of 30% Design Submittal from Civil Design Consultant 6

7 PHI UG Transmission Design Process (Civil) 60% Design Example of 60% Design Submittal from Civil Design Consultant Level A Survey Completed Soil Borings completed and reviewed Design Review and Constructability Review completed 7

8 UG Transmission Design Engineering Cost Total Engineering costs is about 6% of the total project construction cost (excluding cost of materials) Subsurface Utility Engineering (SUE) cost is 50% of the total Engineering cost ( 3% of the total construction cost) 8

9 SUE Benefits Previous Projects Change Order Comparison Due To Utility Conflicts Level of SUE Performed Change Orders Received (Percentage of the Project Construction Cost) Project Construction Cost None 10% $66M MISS Utility Marking and test Pitting Utility Designation and Test Pitting 3% $32M 1.4% $22M 9

10 SUE Benefits (Continued) More accurate design More realistic budget and schedule Less risk for the contractor More contractor participation in the bid Proposals are within tolerance of the cost estimate. Less change orders Less design changes Less risk of dig-ins SUE Challenges Added engineering/design cost (upfront cost) Longer design phase Not all SUE services are equal 10

11 UG Electric Lines Hi Voltage Cables High pressure Pipe Type (HPPT) Self Contained Fluid Filled Gas Oil Dry Cables EPR (Ethylene propylene rubber) XLPE (Cros)s-linked polyethylene Pipe type SCFF XLPE EPR 11

12 UG Electric Lines Construct Pipe Type Duct Banks Direct buried Submarine Manholes (Vaults) Trenchless installations Pipe type Direct Buried 12 Concrete Encased Duct Bank

13 Working In Close Proximity To Pepco Underground Facilities See PROCESS AND PROCEDURES FOR WORKING IN CLOSE PROXIMITY TO PEPCO UNDERGROUND FACILITIES Transmission vs. Distribution Functions Standards Management Records In addition to submitting utility request through Pepco regular channel, please contact PHI Transmission Engineering directly. (Contact info provided at the end of this presentation) Test Holes General Pipe Type Feeders Only PHI approved contractors are qualified to do test holes on PHI transmission lines 13

14 PHI UG Transmission Engineering Contact For UG Transmission utility requests contact: AaRae Alexander Associate Engineer and copy Afshin Avvali, P.E. Sr Engineer or Mousa Hejazi, P.E. Manager Engineering

15 Q & A 15