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