This document discusses load allocation, which is the process of distributing electrical load from a source point to downstream circuit elements. It covers gathering load data, setting up load groups, and choosing a load allocation method. The key points are:
- Load allocation involves distributing kW or amps from a source to downstream circuits based on available load data.
- Gathering load data from sources like substations, feeders, and billing records is the first step.
- Load groups are then set up to define different types of consumers. Common groups include residential and demand loads.
- A load allocation method is chosen for each group, such as length, seasonal, or diversity, depending on the available data and study goals.
2. What we’ll cover today
• Basic overview
• Beyond the basics
– “tricks of the trade” to simplify complex ways
to load allocate
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. 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. 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. Getting Started – Gathering Data
• Decide how to distribute the load
– Billing data
– AMR data
– Distribution transformers
– Geographic model
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. 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.
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. 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.
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%
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. 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. Billing Download
• If you’re using billing information or AMI,
you must get that information into the
model.
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. Load Groups
Available Load Groups
Load Allocation Preferences
Set Up Load Groups
Number of Groups – Up to
four (4)
Names of Groups
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
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. 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. 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. 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. 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. 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. 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. 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. Load Allocation
Now the load can be applied to the groups
that you desire.
Load Allocation can now be performed.
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. 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. 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. 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. 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.