Electric Utility Solutions: Basics of Load Allocation

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Systems engineering and analysis track presentation from Milsoft's 2009 User Conference. It was delivered by Jennifer Taylor and Chris Hammond. The Milsoft Electric Utility Solutions Users Conference is the premier event for both our users and vendors offering interoperable utility management services that enhance Milsoft Smart Grid Solutions. If you’d like to be on our mailing list, just email: missy.brooks@milsoft.com.

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Electric Utility Solutions: Basics of Load Allocation

  1. 1. Basics of Load Allocation Jennifer Taylor, Chris Hammond
  2. 2. What we’ll cover today • Basic overview • Beyond the basics – “tricks of the trade” to simplify complex ways to load allocate
  3. 3. Load allocation • What is it? – The process of distributing kW or Amps per phase load at a given point to the individual circuit elements downline from that point. – Somewhat of an art form, isn’t concrete – Close approximation of actual loading • Isn’t real time
  4. 4. What type of study? • What you are planning to do with the model will determine how you want to approach load allocation: – Planning study = worst case • NCP data for all areas of the study – Specific snapshot in time • Example: planned substation outage – Coincident Data corresponding to the conditions you are examining
  5. 5. Getting started – Gathering Data • First look at what type of data is available – At the “source” (Load Control Point) • Substation: kW or Amp data • Feeders: Amps • Downline LCP – Downline elements • What type of load bearing elements do I have? – Consumers – Line sections
  6. 6. Getting Started – Gathering Data • Decide how to distribute the load – Billing data – AMR data – Distribution transformers – Geographic model
  7. 7. Choose the load allocation method • Length – no billing data required • REA –1950s standard, needs kWh • Seasonal – uses kWh but allows for a % CF (coincidence factor) • Transformer kVA – must have kVA rating for all distribution transformers • kWh – requires kWh from billing file • Diversity – requires kW and maybe kWh or trkVA
  8. 8. Set up Load Groups • Load Groups are used to define “types of consumers.” • Examples of typical load groups: – Residential – kW Demand • Each load group can be assigned a different load allocation method.
  9. 9. Set up Load Groups
  10. 10. Methods and Groups • Deciding on (a) how many load groups and (b) what type of load allocation methods to use go hand in hand. • Understanding how the fixed and allocated methods work together is important in making your decision. • Let’s take a closer look at the Diversity allocation methods.
  11. 11. Diversity: Fixed vs. Allocated • Fixed – Fixed amount of kW for a given load group • Coincidence Factor - % of this fixed amount that will be allocated – Ex. LCP = 10,000kW, Dmd load group total kW =1000kW 80% CF = 800 kW allocated to Dmd load group – Tip: Choose a % CF for your fixed group that will yield the Load Factor that you want for the allocated group.
  12. 12. Diversity: Fixed vs. Allocated
  13. 13. Diversity: Fixed vs. Allocated • Allocated – Allows a load factor to be applied if more than one load group is using an “allocated” method • Ex. Residential users = Residential group Large Power users = kW Demand group Load factor (LF) Residential = 45% Large Powers = 55%
  14. 14. Diversity: Fixed vs. Allocated
  15. 15. More than one group allocated • How does this work? – Step 1: XRESI= Σ kWhRESI / %LFRESI XDMD= Σ kWhDMD / %LFDMD – Step 2: %LCPRESI=LCPTOT* XRESI/(XRESI+ XDMD) %LCPDMD=LCPTOT* XDMD/(XRESI+ XDMD) – Step 3: Allocate kWh group based on kWh. Allocation continues with fixed kW with 100% CF.
  16. 16. What’s Next? • Now that we’ve… – Decided on type of study – Gathered data – Set up load groups – Chosen load allocation methods • Start applying data and allocating load
  17. 17. Billing Download • If you’re using billing information or AMI, you must get that information into the model.
  18. 18. Billing Download • Billing data can be viewed under the Billing Load tab.
  19. 19. Define Load Control Points
  20. 20. Define Load Allocation Settings Run it!
  21. 21. Verify Results
  22. 22. Load Groups Q: Why would you want more—or different—load groups? A: To try and make load allocation better and easier, based on particular characteristics of the load.
  23. 23. Load Groups Available Load Groups Load Allocation Preferences Set Up Load Groups Number of Groups – Up to four (4) Names of Groups
  24. 24. Load Information What type of load information do you have available? kWh kVAr Power Factor Load Factor kW kVA Rate Code Time of Use
  25. 25. Load Information You see your available load information… Now – What do you want to do with it?
  26. 26. Billing Load Setup • Here is the billing load table. Notice the Group Names are down the left side and the load values used are listed across the top.
  27. 27. Billing Load Setup Now you see what is actually used in the load table for allocating load. kW kVAr kWh kVA – Transformer kVA Cons – Number of consumers
  28. 28. Billing Load Setup This is where the rules are set up to place the load into the correct load group. You can even create rules based on data irrelevant to load allocation.
  29. 29. Billing Load Setup These rules allow you to put the load into the correct load groups. Anything in the load file can be used to help filter the load and get sorted into the desired group. In this example, the rate code was used to put load into the Horsepower Load Group. And the “kW > 0” puts the demand loads into the kW Demand Load Group.
  30. 30. Billing Load Setup When setting up Load Rules, if the load fits the rules for one, it will go into it. If there need to be more restrictions, then add the condition in the rules. Example:
  31. 31. Billing Load Setup (1) You know the information that WindMil needs to apply load. (2) Now you need to look at your load file and see what you have. (3) Then you have to figure out how you can use the rules and get the information where you need it.
  32. 32. Billing Load Setup The load file may be either: Space Delimited or Comma Delimited The load file may include the information you want to use. You may have to modify it in another program to get your desired information.
  33. 33. Billing Load File I prefer comma delimited files. They import into Excel very easily for manipulation and checking. In the spreadsheet, the load can be checked for errors. Needed calculations can be performed, such as load factor or power factor.
  34. 34. Load Allocation Now the load can be applied to the groups that you desire. Load Allocation can now be performed.
  35. 35. Why Go Through the Trouble? Separating the load into groups allows you to adjust your load allocation settings to model your circuit best. Diversity Factors, Power Factors, Load Factors
  36. 36. Why Go Through the Trouble? Examples of types of loads that may help load allocation improve your system. Demand loads with poor load factors – actual contribution to peak – coincident factor Pump loads – poor power factor associated with lightly loaded motor conditions Cyclic loads – chicken houses
  37. 37. Why Go Through the Trouble? • To improve system allocated power factor • Having load separated allows the user to adjust the power factor of the residential group and allows the power factor to swing and adjust accordingly for these loads. • Improve existing system model • Improve capacitor recommendations
  38. 38. Why Go Through the Trouble? • For cyclic loads (such as chicken houses). The load may be on only half of month, but the entire demand is on during peak. • For time of use, the load can be allocated for peak condition and for non-peak times to find loading problems with only one load file.
  39. 39. Load Allocation Depending on your available load information, there are ways to improve your system loading to make your model as useful as possible. And all good system models start with good load.

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