Provisioning the Power System for the Porter Farms P.D. By: Marnelli Pascual Christian Brothers University 650 East Parkway S, Memphis TN MAESC CONFERENCE

Overview ●What is Porter Farms P.D.? ●Preliminary Designs ●Loop System ●Specifications ●Calculations ●Cost Analysis ●Project Summary

Porter Farms P.D. Consists of 2 Areas Consists of 2 Areas –Area 1, Subdivision with 69 lots –Area 2, Apartments with 52 units, plus 1 clubhouse Located in Collierville, TN Located in Collierville, TN

Project Location

Project Stages Stage 1 Stage 1 –Develop Area 2, Apartments Stage 2 Stage 2 –Develop Area 1, Subdivision

Existing Power Sources 1Ø 3Ø

Design 1 – Two UG Loops

BORE UNDER RAILROAD

Design 1 (cont’d) BORE UNDER THE STREET

Design 1 (cont’d) Advantages Advantages –Feeds are from the closest sources –No tree trimming/removal required Problems Encountered Problems Encountered –Railroad approval takes at least 90 days –Minimum railroad crossing fee of $75,000

Design 2 – Two UG Loops

LAKE NEW 1Ø OVERHEAD LINE

Design 2 (cont’d) Problems Encountered Problems Encountered –Crossing fee and approval from Railroad company required –City of Collierville and the homeowner’s association objected to the design –Involves tree trimming/removal

Design 3 One UG Loop

TEMPORARY OVERHEAD LINE UNDERGROUND PRIMARY

Design 3 (cont’d) BORE UNDER THE STREET

Design 3 (cont’d) Advantages Advantages –No railroad fee or approval required –No tree trimming/removal Problem Encountered Problem Encountered –Cost of $10,000 for the temporary electric

UG Single Loop Calculated Loads Calculated Loads –Apartments = 525kVA –Subdivision = 775kVA –Total = 1300kVA MLGW Requirement MLGW Requirement –Maximum load = 1320kVA

UG Electrical Loop

Transformer Isolation DISCONNECT

Specifications Fuse: (2) 100 A Fuse: (2) 100 A Transformers Used (Area 1 & 2) Transformers Used (Area 1 & 2) – (3) 50 kVA – (14) 75 kVA – (1) 100 kVA Cables & Conduits Cables & Conduits –Primary: #2 insulated copper inside 2” pvc conduit –Secondary: 350 kCM triplex inside 3” pvc conduit Meter Sockets (Apartments) Meter Sockets (Apartments) –(12) 6-Gang Meter – (2) 2-Gang Meter – (1) Single Meter

Specifications (cont’d) 6-Gang Meter Socket 6-Gang Meter Socket RISER ENTRY

Specifications (cont’d) Location of Facilities Location of Facilities – Riser Location

Specifications (cont’d) Location of Facilities Location of Facilities – Transformer Location (Apartments)

Specifications (cont’d) Location of Facilities Location of Facilities – Transformer Location (Subdivision)

Calculations Cost: Software-calculated Cost: Software-calculated Fuse: No calculation needed Fuse: No calculation needed Cables & Conduits Cables & Conduits –Size: Software-calculated based on cable length and load –Length: Measured from map

Calculations (cont’d) Cable Tension, ≤ 850 lbs. Cable Tension, ≤ 850 lbs. – Maximum Tension = 831 lbs. – Software-calculated

Calculations (cont’d) Transformer Size (Apartments) Transformer Size (Apartments) Load from Electrician, kWDemand FactorProjected Load, kW Lighting Receptacle Range Dryer Air Conditioning Total Load per Unit Total Load per Unit=  (Load from Electrician)(Demand Factor) Equation 1

Calculations (cont’d) Transformer Size (Apartments) Transformer Size (Apartments) Transformer Load=(Total Load per Unit)(No. of Unit)(Demand Factor) Equation 2 No. of BuildingsNo. of Units Demand Factor Transformer Load Transformer Size to Use kVA kVA Calculated Total Load per Unit = kVA

Calculations (cont’d) Transformer Size (Subdivision) Transformer Size (Subdivision) Number of LotsLoad Based on Sq. Ft., kVATransformer Size kVA kVA House Square Footage: 2500 sq. ft.

Project Cost SubdivisionApartments Total Cost$109,881.08$65, Cost per Lot/Unit $1,592.48$1, Average Cost per Lot/Unit $1,594.00$679.00

Apartments Cost TransformerSecondary Cable Primary Cable QuantityCost, $Length, ft.Cost, $ Project C Project C

Apartments Cost (cont’d) TransformerSecondary Cable Primary Cable QuantityCost, $Length, ft.Cost, $ Project C Project C

Project Summary –All requirements were met –MLGW and the customer approved the final design –Project is currently under construction

Questions