1. Transmission and Distribution Loss Study
Virgin Islands Water and Power Authority
June 2008

2. Purpose Quantify T&D facility losses using available tools
Provide a basis for recommendations to reduce T&D system losses
Prioritize recommendations based on impact to T&D losses

3. Results of Loss Study - St. Thomas FY 2007

4. Results of Loss Study – St. Croix FY 2007

5. Results of Loss Study FY 2007 System Statistics Type STT STX
Cost of Power (1) ($/kWh)
$0.164
$0.195
Annual Cost of Losses (2) ($/peak kW)
$817.51
$1,032.71
Transmission (mi) 30
N/A
Distribution (mi)
339
479
Number of Customers
32,369
25,839
System Peak (MW)
88.1
54.1
Notes: (1) Based on fuel costs for FY 2007, only (2) Calculated costs of losses based on cost of power for FY 2007.

6. Basis of Analysis & Assumptions
Engineering models of T&D system loads at FY 2007 peak
FY 2007 system energy & peak demand, and financial statistics
VIWAPA and industry standards
Cost of losses based on FY 2007 fuel cost only
Customer load based on transformer size
Secondary lengths and types based on averages
Load factors per customer class based on 2007 system load factor

7. Strategies to Reduce T&D Losses
Support, maintain, and upgrade engineering models
Standardize distribution transformer sizing for more efficient use of capacity
Increase maintenance practices
Use economic analysis to select conductors for construction, upgrades, and conductor replacement program

8. Strategies to Reduce T&D Losses
Implement new DOE Transformer Efficiency Standards
GPS inventory of system facilities
Improve voltage regulation on T&D systems
Add proposed substation for St. Croix
Add line regulation as interim solution for proposed substation
Accelerate tree trimming program
Increase infrared camera inspections

9. Strategies to Reduce Other System Losses
Improve QA/QC of collected metering data
Ensure billing processes are timely and accurate
Implement Automated Meter Reading (AMR) system-wide
Without AMR:
Accelerate meter calibration program
Continue focus on meter resealing and meter lock ring programs
Reconcile unmetered lighting accounts
Field verification of light operation