Presentation is loading. Please wait.

Presentation is loading. Please wait.

Distribution Transformer Size Optimization by Forecasting Customer Electricity Load Jarrod Luze Black Hills Power Rapid City, South Dakota.

Similar presentations


Presentation on theme: "Distribution Transformer Size Optimization by Forecasting Customer Electricity Load Jarrod Luze Black Hills Power Rapid City, South Dakota."— Presentation transcript:

1 Distribution Transformer Size Optimization by Forecasting Customer Electricity Load Jarrod Luze Black Hills Power Rapid City, South Dakota

2 Introduction Electric utilities face common challenges determining transformer sizes. Electric utilities face common challenges determining transformer sizes. Study consists of 960 three phase pad- mounted transformers. Study consists of 960 three phase pad- mounted transformers. Research and categorization of existing transformersResearch and categorization of existing transformers Ideal vs. actual benefit/cost analysisIdeal vs. actual benefit/cost analysis Forecasting future customer power demandForecasting future customer power demand

3 Study of Existing Transformers in Service Compared kVA name-plate rating to peak demand of customer Compared kVA name-plate rating to peak demand of customer R+_ signifies that a transformer is undersized and would ideally require a larger transformer for the load. R+_ signifies that a transformer is undersized and would ideally require a larger transformer for the load. R-_ signifies the transformer is under- loaded, and a smaller transformer would suffice. R-_ signifies the transformer is under- loaded, and a smaller transformer would suffice.

4 Study of Existing Transformers in Service Out of 960, 605 were oversized-63% Out of 960, 605 were oversized-63% Over 10% at least 3 sizes too big Over 10% at least 3 sizes too big 150 kVA, 300 kVA and 500 kVA are the least accurately sized 150 kVA, 300 kVA and 500 kVA are the least accurately sized Very few transformers over-loaded Very few transformers over-loaded Overall results of study show an overly conservative sizing method Overall results of study show an overly conservative sizing method

5 Existing Transformers in Service

6 Study of Existing Transformers in Service

7 Financial Analysis Capital expense of the equipment Capital expense of the equipment Operating cost = No-load power loss Operating cost = No-load power loss Wholesale electricity rate of $0.04/kWH was used Wholesale electricity rate of $0.04/kWH was used

8 Financial Analysis – Capital Estimated by using the price of the most recently purchased transformer of that size Estimated by using the price of the most recently purchased transformer of that size Sums entire purchase price* of the 960 transformers (total capital expense) Sums entire purchase price* of the 960 transformers (total capital expense) *Purchase price includes installation costs Theoretical estimated purchase cost vs. actual estimated purchase cost Theoretical estimated purchase cost vs. actual estimated purchase cost

9 Financial Analysis

10 Financial Analysis – Operating No-load power loss (Watts) No-load power loss (Watts) Not considered: Not considered: Full-load loss, repairs and maintenanceFull-load loss, repairs and maintenance Conservative estimateConservative estimate PF of 0.95 used, if unable to gather from database PF of 0.95 used, if unable to gather from database

11 Financial Analysis No-Load Power Loss (O&M)

12 Financial Analysis - Overall Assuming sizing methods and results are consistent for all BHP transformers Three-phase, pad-mount share of the transformerThree-phase, pad-mount share of the transformer purchase cost is roughly 26% of the $2.5 million annual transformer purchase cost budget purchase cost is roughly 26% of the $2.5 million annual transformer purchase cost budget At 17%, $425,000 annual benefitAt 17%, $425,000 annual benefit

13 Research Application Increase efficiency from the sizing statistics Increase efficiency from the sizing statistics Possibilities Possibilities Review current transformer placement, and change-out existing units based on economic feasibility.Review current transformer placement, and change-out existing units based on economic feasibility. Develop more accurate transformer sizing methodDevelop more accurate transformer sizing method

14 Forecasting Customer Electricity Loads Many factors Many factors Size of structure to be poweredSize of structure to be powered General purpose of structureGeneral purpose of structure Structural componentsStructural components Machines and Appliances to be installedMachines and Appliances to be installed LocationLocation Personnel capacity of building or structurePersonnel capacity of building or structure

15 Customer Categories This study includes This study includes Retail StoresRetail Stores Business officesBusiness offices Apartments (gas heated, electric heat)Apartments (gas heated, electric heat) Many others to be considered, time- constraints limit this studyMany others to be considered, time- constraints limit this study

16 Data Collection and Calculation Cooperation of Customers Cooperation of Customers Tax Equalization office supplied square footage information Tax Equalization office supplied square footage information Averages based on Peak kVA demands Averages based on Peak kVA demands Power factor assumed 0.95 if Unavailable in database Power factor assumed 0.95 if Unavailable in database Calculations of W/sf, mA/sf Calculations of W/sf, mA/sf Consistent values, low standard of deviation in dataConsistent values, low standard of deviation in data

17 Results – Business Offices Averaged 5.76 watts per square foot Averaged 5.76 watts per square foot Highest: 7.09 Lowest: 4.52 W/sqft Highest: 7.09 Lowest: 4.52 W/sqft Averaged 34% of Main Switch Ampacity Averaged 34% of Main Switch Ampacity Mainly fluorescent lighting Mainly fluorescent lighting Gas heated Gas heated

18 Business Offices

19 Results - Retail Stores Averaged 4.98 W/sqft Averaged 4.98 W/sqft High: 8.13 / Low: 2.86 High: 8.13 / Low: 2.86 Averaged 46% of Main Switch Ampacity Averaged 46% of Main Switch Ampacity Mostly Fluorescent Lighting, some spot lighting Mostly Fluorescent Lighting, some spot lighting

20 Retail Stores

21 Results - Apartments Gas Heated, summer peaking, 94.7% occ. Gas Heated, summer peaking, 94.7% occ. Averaged 1.42 W/sqft, %Averaged 1.42 W/sqft, % High: 2.09 / Low: 0.82High: 2.09 / Low: 0.82 Electric Heat, winter peaking, 81.5% occ. Electric Heat, winter peaking, 81.5% occ. Averaged 3.53 W/sqft, %Averaged 3.53 W/sqft, % High: 4.14 / Low: 2.71High: 4.14 / Low: 2.71

22 Apartment Buildings

23 Applications Gives utility representatives statistics when discussing options with customers & contractors. Gives utility representatives statistics when discussing options with customers & contractors. Presents evidence & factual history to help decide on transformer size. Presents evidence & factual history to help decide on transformer size. Provides foundation and structure for further research of future demand and transformer sizing. Provides foundation and structure for further research of future demand and transformer sizing.

24 Summary Sizing analysis shows significant cost avoidance capabilities: Sizing analysis shows significant cost avoidance capabilities: 17% $425,00017% $425,000 O&M savings (NLL only) of 31%O&M savings (NLL only) of 31% Customer demand indicators may help utility reps with transformer sizing, and provide a basis to advance research Customer demand indicators may help utility reps with transformer sizing, and provide a basis to advance research

25 Questions?


Download ppt "Distribution Transformer Size Optimization by Forecasting Customer Electricity Load Jarrod Luze Black Hills Power Rapid City, South Dakota."

Similar presentations


Ads by Google