Download Reducing Losses Using Windmil

Reducing Losses Using WindMil
Jennifer Taylor
Distribution System Solutions, Inc
Loss Reduction Analysis Modes
• Feeder Optimization
• Load Balance
• Capacitor Placement
Feeder Optimization
Feeder Optimization
• Aides in finding the optimal location for open
points between feeders to best reduce kW
losses.
Sample Substations
kW Losses = 209kW
Feeder Optimization Setup
Limits the number of switching
operations at each step.
Adds suggested open points.
Feeder Optimization Setup
Set limits based on your design
criteria: contingency or normal
operation?
Use inflated overages if you know
the capacities aren’t accurately
defined in the EQDB.
Feeder Optimization Setup
Choose colors to display results.
Feeder Optimization Results
Feeder Optimization Results
Feeder Optimization Cost Savings
•
•
•
•
•
Losses before feeder opt.= 209kW
3 pairs of switching = $1500
Losses after balancing = 184kW
Reduction in losses = 25kW
30 year present worth = $48,845
Load Balance
Load Balance
•
•
•
•
Voltage shifts: excessive Voltage Drop or Rise
Increased return currents
Wasted use of capacity
Increased losses
– The imbalance of current will increase the I2R
losses.
I2R Losses
• Let’s look at a simple math exercise:
• Total Current = 600A
A
B
C
Balanced
Amps
I2
200 40,000
200 40,000
200 40,000
Total = 120,000
Imbalanced
Amps
I2
A
300 90,000
B
200 40,000
C
100 10,000
Total = 140,000
Sample Circuit – Before Balancing
103kW in losses
Load Balance Setup
Always choose “Fast”
Choose whether to run on whole
circuit or partial
Set up Voltage Drop
Sample Circuit – After Balancing
81kW in losses
Our Sample Circuit: Loss Savings
•
•
•
•
•
Losses before balancing = 104kW
2 tap phase changes = $500
Losses after balancing = 81kW
Reduction in losses = 23kW
30 year present worth = $17,906
Capacitor Placement
Capacitor Placement
• Increase in net kVAR means an increase in kVA
and current levels on the system
– Available capacity on equipment decreases
– Equipment sizes come into question if they were
sized only on kW
– Line losses increase (I2R)
Capacitor Placement
• Proper Capacitor placement becomes
essential
– Need to know where to place Cap units to provide
greatest benefit to our systems
– Where to optimize for biggest loss reduction
Sample Substation
G&T complaining about low power factor at
substation
• Substation nearing kVA capacity limit
• Avg Power Factor = 89.94%
• Load Factor = 54.5%
• Peak kW = 8,500kW
• Peak kVAR = 4,400kVAR
Sample Substation
300kVAR
closed
600kVAR
open
VAR profile over one year
Week Profile
kVAR
kW
Setting up kVAR in model
Known data:
• PF at peak at substation = 88.8
• Peak summer kW = 8,500kW
• Known power factor at 2 industrial sites
Assumptions/Estimates:
• Large/Small Commercial pf = 90%
• Residential pf = 95%
Load Allocation Settings
Force kW Demand (Industrial) to swing.
Load Allocation
Capacitor Placement Setup
Set Power Factor
desired limits.
Capacitor Placement Setup
Set Bank size
restrictions.
Capacitor Placement Setup
Set other
restrictions on
placement.
Capacitor Placement Setup
Choose color
options.
Results at full load:
Add 600kVAR
Add 300KVAR
Results at full load:
VAR profile: All Fixed
2,100kVAR added
Look at Using Some Switched Caps
Add in steps as load increases.
Adjust for any changes in pf
based on load changes.
Adding Staged Capacitors
25072: Switched
24917: Switched
Keep Existing
Fixed
24258: Fixed
56178: Fixed
VAR Profile with Added Caps
600 kVAR more switched
1500kVAR fixed
Our Sample Sub: Loss Savings
• Losses before adding caps = 120kW
• Adding one set of controls and one 300kVAR
switched bank = $12,000
• Losses after adding caps = 112kW
• Reduction in losses = 8kW
• 30 year present worth = $16,950
In closing
• Even small kW loss reduction can amount to
big long-term savings.
• Feeder Optimization, Load Balance, and Cap
Placement features in WindMil can be great
tools to use as starting points for making
decisions to make your system more efficient.