Introduction ................................................................................................................................................1
Measurement Quantities............................................................................................................................1
Volume..................................................................................................................................................1
Pressure................................................................................................................................................2
Energy...................................................................................................................................................2
Estimating Gas Loads................................................................................................................................2
Load Classification.....................................................................................................................................2
Firm Loads............................................................................................................................................2
Off-Peak Loads.....................................................................................................................................3
Interruptible Loads................................................................................................................................3
Benefits of Off-Peak and Interruptible Loads........................................................................................4
Load Analysis............................................................................................................................................4
Single-Family Homes............................................................................................................................4
Customer Group Loads.........................................................................................................................5
Distribution Piping Networks.................................................................................................................5
Application of Load Factors.......................................................................................................................6
Verification of Design Conditions...............................................................................................................7
Gas Load Estimating Example..................................................................................................................7
Demand / Coincidental Factors.............................................................................................................8
Load Factors..............................................................................................................................................9
Annual Load Factors.............................................................................................................................9
Weather Factors..................................................................................................................................10
Applications of the Degree-Day Index.................................................................................................11
Wind Factors.......................................................................................................................................12
Forecasting Future Loads........................................................................................................................13
Computerized Load Gathering............................................................................................................14
Finder Systems...................................................................................................................................14
Errors, Pitfalls, and Sources of Inaccuracy.........................................................................................14
Validation............................................................................................................................................15
Load Growth Patterns.........................................................................................................................16
Information Sources............................................................................................................................17
3-ii GAS DISTRIBUTION SELF-STUDY COURSE
LIST OF TABLES
Page
Table 3-1: Typical Gas Loads for a Single-Family Home.........................................................................5
Table 3-2: Coincidence Load Factors.......................................................................................................8
Table 3-3: Load Factor Adjustments.......................................................................................................10
Table 3-4: Annual Degree-Day Occurrence for Select American Cities.................................................12
Table 3-5: Constants Used in Wind Correction Equation.......................................................................13
Table 3-6. Information Sources for Use in Forecasting Locations and Demands of Small-Volume Residential Consumers........................................................................................................17
LIST OF FIGURES
Page
Figure 3-1: A Single Family Home is a Firm Load....................................................................................3
Figure 3-2: Off-Peak Customer Gas Load................................................................................................3
Figure 3-3: Electric-Generating Plant.......................................................................................................4
Figure 3-4: Typical Gas Appliances..........................................................................................................5
Figure 3-5: Distribution Pipe Network.......................................................................................................6
Figure 3-6: 10-unit Condominium Building...............................................................................................8
Figure 3-7: Figure of Street Intersection Showing Node Numbers and Finders.....................................15
Figure 3-8: Figure of Area Load Growth Patterns...................................................................................16
