Provisioning the Power System for Provisioning the Power System for the Porter Farms P.D.the Porter Farms P.D.

By: Marnelli PascualBy: Marnelli Pascual

Christian Brothers UniversityChristian Brothers University650 East Parkway S, Memphis TN 38104650 East Parkway S, Memphis TN 38104

MAESC CONFERENCE - 2005MAESC CONFERENCE - 2005

OverviewOverview

● What is Porter Farms P.D.?What is Porter Farms P.D.?

● Preliminary DesignsPreliminary Designs

● Loop SystemLoop System

● SpecificationsSpecifications

● CalculationsCalculations

● Cost AnalysisCost Analysis

● Project SummaryProject Summary

Porter Farms P.D.Porter Farms P.D.

Consists of 2 AreasConsists of 2 Areas– Area 1, Subdivision with 69 lotsArea 1, Subdivision with 69 lots– Area 2, Apartments with 52 units, plus Area 2, Apartments with 52 units, plus

1 clubhouse1 clubhouseLocated in Collierville, TNLocated in Collierville, TN

Project Location

Project StagesProject Stages

Stage 1Stage 1– Develop Area 2, ApartmentsDevelop Area 2, Apartments

Stage 2Stage 2– Develop Area 1, SubdivisionDevelop Area 1, Subdivision

Existing Power Sources

1Ø

3Ø

3Ø

Design 1 – Two UG Loops

Design 1 – Two UG Loops

SUBDIVISION

APARTMENTS

25

27

32

28 20 18

12

10

17

13

19

11

BORE UNDER BORE UNDER RAILROADRAILROAD

Design 1 (cont’d)

WINCHESTER

SUBDIVISION

APARTMENTS

BORE UNDER BORE UNDER THE STREETTHE STREET

Design 1 (cont’d)Design 1 (cont’d)

AdvantagesAdvantages– Feeds are from the closest sourcesFeeds are from the closest sources– No tree trimming/removal requiredNo tree trimming/removal required

Problems EncounteredProblems Encountered– Railroad approval takes at least 90 Railroad approval takes at least 90

daysdays– Minimum railroad crossing fee of Minimum railroad crossing fee of

$75,000$75,000

Design 2 – Two UG Loops

Design 2 – Two UG Loops

19

17

SUBDIVISION

APARTMENTS

11

13

LAKE NEW 1Ø NEW 1Ø OVERHEAD OVERHEAD LINELINE

Design 2 (cont’d)Design 2 (cont’d)

Problems EncounteredProblems Encountered– Crossing fee and approval from Crossing fee and approval from

Railroad company requiredRailroad company required– City of Collierville and the City of Collierville and the

homeowner’s association objected to homeowner’s association objected to the designthe design

– Involves tree trimming/removalInvolves tree trimming/removal

Design 3One UG Loop

Design 3One UG Loop

TEMPORARY TEMPORARY OVERHEAD OVERHEAD LINELINE

UNDERGROUNUNDERGROUND PRIMARYD PRIMARY

Design 3 (cont’d)

WINCHESTER

SUBDIVISION

APARTMENTS

BORE UNDER BORE UNDER THE STREETTHE STREET

Design 3 (cont’d)Design 3 (cont’d)

AdvantagesAdvantages– No railroad fee or approval requiredNo railroad fee or approval required– No tree trimming/removalNo tree trimming/removal

Problem EncounteredProblem Encountered– Cost of $10,000 for the temporary Cost of $10,000 for the temporary

electricelectric

UG Single LoopUG Single Loop

Calculated LoadsCalculated Loads– Apartments = 525kVAApartments = 525kVA– Subdivision = 775kVASubdivision = 775kVA– Total = 1300kVATotal = 1300kVA

MLGW RequirementMLGW Requirement– Maximum load = 1320kVAMaximum load = 1320kVA

UG Electrical Loop

Transformer Isolation

DISCONNECTDISCONNECT

SpecificationsSpecifications Fuse: (2) Fuse: (2) 100 A100 A Transformers Used (Area 1 & 2)Transformers Used (Area 1 & 2)

– (3) 50 kVA(3) 50 kVA– (14) 75 kVA(14) 75 kVA– (1) 100 kVA(1) 100 kVA

Cables & ConduitsCables & Conduits– Primary: #2 insulated copper inside 2” pvc conduitPrimary: #2 insulated copper inside 2” pvc conduit– Secondary: 350 kCM triplex inside 3” pvc conduitSecondary: 350 kCM triplex inside 3” pvc conduit

Meter Sockets (Apartments)Meter Sockets (Apartments)– (12) 6-Gang Meter (12) 6-Gang Meter – (2) 2-Gang Meter(2) 2-Gang Meter– (1) Single Meter(1) Single Meter

Specifications (cont’d)Specifications (cont’d)

6-Gang Meter Socket6-Gang Meter Socket

RISER ENTRY

Specifications (cont’d)Specifications (cont’d)

Location of FacilitiesLocation of Facilities– Riser LocationRiser Location

Specifications (cont’d)Specifications (cont’d)

Location of FacilitiesLocation of Facilities– Transformer Location (Apartments)Transformer Location (Apartments)

Specifications (cont’d)Specifications (cont’d)

Location of FacilitiesLocation of Facilities– Transformer Location (Subdivision)Transformer Location (Subdivision)

CalculationsCalculations

Cost: Cost: Software-calculated Software-calculated

Fuse: Fuse: No calculation neededNo calculation needed

Cables & ConduitsCables & Conduits– Size: Software-calculated based on Size: Software-calculated based on

cable length and loadcable length and load– Length: Measured from mapLength: Measured from map

Calculations (cont’d)Calculations (cont’d)

Cable Tension, Cable Tension, ≤ 850 lbs.≤ 850 lbs.– Maximum Tension = 831 lbs.Maximum Tension = 831 lbs.– Software-calculatedSoftware-calculated

Calculations (cont’d)Calculations (cont’d)

Transformer Size (Apartments)Transformer Size (Apartments)

  Load from Electrician, kW Demand Factor Projected Load, kW

Lighting 4.00 0.5 2.00

Receptacle 4.00 0.4 1.60

Range 7.00 0.6 4.20

Dryer 6.00 0.6 3.60

Air Conditioning 3.50 0.8 3.92

Total Load per Unit 15.32

Total Load per Unit = (Load from Electrician)(Demand Factor)Equation 1

Calculations (cont’d)Calculations (cont’d)

Transformer Size (Apartments)Transformer Size (Apartments)

Transformer Load = (Total Load per Unit)(No. of Unit)(Demand Factor)Equation 2

No. of Buildings No. of Units

Demand Factor

Transformer Load

Transformer Size to Use

2 8 0.7 85.792 100 kVA

1 4 0.8 49.024 50 kVA

Calculated Total Load per Unit = 15.32 kVA

Calculations (cont’d)Calculations (cont’d)

Transformer Size (Subdivision)Transformer Size (Subdivision)

Number of Lots Load Based on Sq. Ft., kVA Transformer Size

4 36.7250 kVA

5 44.56

6 52.36

75 kVA

7 61.58

8 65.69

9 68.62

10 70.38

House Square Footage: 2500 sq. ft.

Project CostProject Cost

Subdivision Apartments

Total Cost $109,881.08 $65,701.85

Cost per Lot/Unit

$1,592.48 $1,239.66$1,239.66

2003 Average Cost per Lot/Unit

$1,594.00 $679.00

Apartments CostApartments Cost

 

Transformer Secondary CablePrimary Cable

Quantity Cost, $ Length, ft. Cost, $

Project 1 1 2586 200 1710 C

Project 2 2 5170 80 844 C

Apartments Cost (cont’d)Apartments Cost (cont’d)

 

Transformer Secondary CablePrimary Cable

Quantity Cost, $ Length, ft. Cost, $

Project 1 1 2586 200 1710 C

Project 2 2 5170 80 844 C

Project SummaryProject Summary

– All requirements were metAll requirements were met– MLGW and the customer approved the MLGW and the customer approved the

final designfinal design– Project is currently under constructionProject is currently under construction

QuestionsQuestions