2013 uc voltage optimization and cvr case study - tyler patton
TRANSCRIPT
Conservation Voltage Reduction and Voltage Optimization
Tyler Patton - SAIC
Overview • System statistics and drivers for CVR / VO • What is CVR? • Why does CVR work? • What is VO? • Why implement VO? • Case study
CVR = Conserva-on Voltage Reduc-on VO = Voltage Op-miza-on
System Statistics • 198.8 MW peak • 640,620.5 MWh annual energy purchases
• 603,030.3 MWh annual energy sales
• 31,200 members
• 7 distribution substations
• 2,200 miles of distribution
• Distribution is operated at 12.5/7.2 kV
MW = Megawatt MWh = Megawatt-hour kV = kilovolt
Potential Drivers for a Utility • New technologies can improve operation, monitoring, and
control • New rates from power supplier • Opportunity to receive grant funding from the power supplier • Support robust SCADA implementation plan • Stewards of our systems
– Optimize to improve efficiency and leverage existing assets – Postpone expensive system upgrades or investments – Provide cost-effective solutions for utility and members
SCADA = Supervisory Control and Data Acquisition
What Is Conservation Voltage Reduction?
End of Feeder
At Substation
Minimum Allowable Voltage on Primary Line
∆V = 1.5V
5 V = Volts
Why Does Conservation Voltage Reduction Work? Load Types
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Source: IEEE Std 399-1980 – Recommended Practice for Industrial & Commercial Power System Analysis (Brown Book)c
S Si
V Vi
= k( )( )
k = 0 Constant SPQ
k = 1 Constant I k = 2 Constant Z
PU = Per Unit S = Constant Power Si = Constant Power V = Volts Vi = Voltage SPQ= Constant Power I = Constant Current Z = Constant Impedance IEEE = Ins-tute of Electrical and Electronics Engineers
What Is Voltage Optimization?
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1. Voltage optimization • Combina-on of distribu-on efficiency and conserva-on voltage reduc-on
2. Why distribution efficiency? • System improvements reduce losses and flaJen voltage profile • More distribu-on systems can take advantage of CVR • Ensures a certain level of distribu-on system stability • Reduces risk of supplying low voltage to customers
CVR = Conserva-on Voltage Reduc-on
126 Volts
120
114
121 126 125 124 122 123
Nor
mal
Vo
ltage
O
pera
tion
Average Voltage Standard Practice
Normal Voltage Operating Range in Current Practice by Utilities
What Is Voltage Optimization?
Feeder Length
Voltage At Min
Voltage At Peak
8
126 Volts
120
114
CVR
– L
ower
Vo
ltage
Average Voltage Standard Practice
Average Voltage CVR
ΔV
Feeder Length
Conservation Voltage Reduction – Lowering the Voltage
Apply Line Drop Compensation: • Changes voltage profile and allows additional voltage reduction
121 126 125 124 122 123 120 124 123 123 121 122
9 CVR = Conserva-on Voltage Reduc-on V = Volts
126 Volts
120
114
Volta
ge
Opt
imiz
atio
n
Average Voltage Standard Practice
Average Voltage CVR
ΔV
Feeder Length
Voltage Optimization
Voltage Optimization: • Flattens voltage profile and allows additional voltage reduction
120 124 123 123 121 122 115 120 119 118 116 117
Average Voltage VO Practice
• Mitigates/prevents risk of low voltage and customer power quality issues.
ΔV Increased
!
10 CVR = Conserva-on Voltage Reduc-on V = Volts VO = Voltage Op-miza-on
Case Study: Substation A • (2) 161-12.47 kV, 25/33.3/41.6-46.7 MVA transformers • (6) 12.5/7.2 kV distribution feeders • 300 miles of distribution • 4,600 members • 19.9 MW peak at 96% Pf (Summer) • 20.6 MW peak at 98% Pf (Winter) • Regulated at 126 V
11 kV = kilovolts MVA = Megavolt-‐amperes MW = MegawaJ Pf = Power Factor V = Volts
Case Study: Strategies • Strategies evaluated
– Load balancing – Capacitor placement – Reduce voltage with LTC and regulators – Add monitoring points, as needed
• Other strategies available – Multi-phasing – Feeder and substation load optimization – Reconductor backbone
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Goal: Reduce losses
and flatten voltage profile
LTC = Load Tap Changer
Case Study: Performance Thresholds
1. Phase balancing – loss savings > 1 kW
2. Feeder power factor > 99%
3. Voltage at meter > 114 V and < 126 V (ANSI® range)
4. Monitoring points for voltages > 115 V
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ANSI is a registered trademark of American National Standards Institute in the U.S. and/or other countries.
MW = MegawaJ V = Volts ANSI = American Na-onal Standards Ins-tute kW = kilowaJ
Case Study: Voltage Reduction Event
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• Percentage Voltage Reduction – 5.0% (T1); 3.5% (T2)
• Percentage Demand Reduction – Unknown – Used same time period for three days prior to the event to trend change in demand
• Estimated % Demand Reduction – 4.47% (T1); 2.09% (T2)
• CVR Factor = % 𝐷𝑒𝑚𝑎𝑛𝑑 𝑅𝑒𝑑𝑢𝑐𝑡𝑖𝑜𝑛/% 𝑉𝑜𝑙𝑡𝑎𝑔𝑒 𝑅𝑒𝑑𝑢𝑐𝑡𝑖𝑜𝑛
– 0.89 (T1); 0.60 (T2) T1 = Transformer 1 T2 = Transformer 2 CVR = Conserva-on Voltage Reduc-on
Case Study: Load Mix (Summer)
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• Transformer 1 CVR Factor = 0.89 – %Z = 8 – %I = 82 – %PQ = 10
• Transformer 2 CVR Factor = 0.60 – %Z = 7 – %I = 53 – %PQ = 40
CVR = Conserva-on Voltage Reduc-on Z = Constant Impedance I = Constant Current
Case Study: Recommendations
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Jena Substation Change Phase of
Taps
Regulators Capacitors Add Monitoring Points Add Remove Add Remove
Transformer 1
Feeder 1 1 1
Feeder 2 3 1 1 1
Feeder 3 1 1 1 1
Transformer 2
Feeder 1 2 1 1
Feeder 2 1 2 1
Feeder 3 3 2 1
Case Study: Analysis Summary
17 MW = MegawaJ
Case Study: Analysis Summary
10.0
20.0
30.0
4:00
4:20
4:40
5:00
5:20
5:40
6:00
6:20
6:40
7:00
7:20
7:40
8:00
8:20
8:40
9:00
9:20
9:40
10:00
Dem
and (MW)Estimated Reduction with CVR/VO
CVR/VO
Substation A
18 CVR = Conserva-on Voltage Reduc-on VO = Voltage Op-miza-on MW = MegawaJ
Case Study: Analysis Summary
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Notes: 1. Assumes CVR event at summer and winter peak at a demand rate of $8/kW 2. Assumes four-hour duration of CVR event for the summer and winter peaks and an energy rate of $0.05/kWh
Average Voltage
Reduction (ΔV)
Estimated Demand Savings (1)
Estimated Energy Savings (2)
Total Estimated Annual Savings
($) (kW) Annual ($) (kWh) Annual ($)
Summer Peak 3.5 V (2.78%) 3,505 $28,040 14,020 $701 $28,741
Winter Peak 3.8 V (3.10%) 3,868 $30,944 15,472 $773 $31,717
Annual Total - 7,373 $58,984 29,492 $1,475 $60,459
V = Volts CVR = Conserva-on Voltage Reduc-on kW = kilowaJ kWh = kilowaJ-‐hour
Thank You
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Tyler Patton Associate Engineer, Transmission and Distribution Planning and Analysis 131 Saundersille Road, Suite 300 | Hendersonville, TN 37075 Tel: 615.431.3245 | Email: [email protected] Visit us at saic.com