cm_apw_2015
TRANSCRIPT
Power 101Introduction to Transformers for Residential and Industrial Applications
ABB Automation & Power World: March 2-5, 2015
© ABBSlide 2May 3, 2023
Power 101Introduction to Distribution Transformers for Residential and Industrial Applications
Chris Morrow Power & Automation Leaders Program
ABB - Jefferson City, MO
Liquid Filled Distribution Transformers
Kevin Liu Product Manager – Dry-type transformers NAM
ABB - Bland, VA
Dry-type Distribution Transformers
© ABBSlide 3May 3, 2023
Safety Is Everyone’s Responsibility.
All Accidents Are Preventable.
© ABBSlide 4May 3, 2023
Your safety is important to usPlease be aware of these emergency procedures
In the event of an emergency please call the emergency numbers above... Do not dial 9-1-1 directly.
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Do not re-enter the building until advised by Convention Center personnel or an “all clear” announcement is made.
Emergency numbers: Dial 8087 from any house phoneor (713) 853-8087 from any cell phone or outside line
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Know your surroundings: Identify the area you are in Locate the nearest two exits
© ABBSlide 6May 3, 2023
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© ABBSlide 7May 3, 2023
George R. Brown Convention Center Level three
Know your surroundings: Identify the meeting room you are in Locate the nearest two exits
© ABBSlide 8May 3, 2023
Introduction to Transformers for
Residential and Industrial Applications
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Presentation Outline
Transformer Purpose What Does a Transformer Do? How Does it Work?
Electrical Design Characteristics Transformer Losses Efficiency & Impedance Example Design
Design Considerations and Flexibility Core Type Winding Material Winding Connections System Connection Transformer Configuration Tank Material
Product Requirement Considerations Cooling Methods Monitoring Devices Protection Devices
Application Considerations Functional Examples
Loss Evaluation
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Presentation Outline
Transformer Purpose What Does a Transformer Do? How Does it Work?
Electrical Design Characteristics Transformer Losses Efficiency & Impedance Example Design
Design Considerations and Flexibility Core Type Winding Material Winding Connections System Connection Transformer Configuration Tank Material
Product Requirement Considerations Cooling Methods Monitoring Devices Protection Devices
Application Considerations Functional Examples
Loss Evaluation
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What Does a Transformer Do?
Changes voltage level on a power system
Step up - increase voltage Step down - decrease voltage
Allows for long distance, high voltage power transmission
Generator step up transformers Power transmission transformers Distribution transformers
Distribution transformer:
The final voltage change to meet customer needs in the power network
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11000 VOLTSGENERATED
POWER HOUSEVOLTAGE INCREASES
NETWORK FAULT
66000 VOLT TRANSMISSION
SUB-STATION FROMTRANSMISSION LINE
INDUSTRIAL CUSTOMER
1st VOLTAGE REDUCTION(TRANSMISSIONSUBSTATION)
4000 VOLT DISTRIBUTION
2nd VOLT REDUCTION(DISTRIBUTIONSUBSTATION)
POWER CENTERINDUSTRIAL PLANT
22000 VOLTS LOW VOLTAGE TRANSMISSION
SUB-STATION FROMLOW VOLTAGE TRANSMISSION
Electrical Service From The Generator To The Customer
SUBWAY VAULT
COMMERCIALCUSTOMER
15
DISTRIBUTIONTRANSFORMER
RESIDENTIALCUSTOMER
120/240VOLTS
GenerationTransmission
Distribution
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How Does it Work?
A transformer consists of two windings on the same iron core Primary & secondary (HV & LV)
Primary winding (1) receives AC power from external source
AC current in the primary winding produces varying magnetic field in the core
Varying magnetic field induces current and voltage in the secondary winding (2)
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How Does it Work?
Flux, Φ
Flux, Φ
AC Current (amps) α Δ in Magnetic field (B) Faraday’s Law
HighVoltageLowVoltage
=TurnsHVTurnsLV
=𝐓𝐮𝐫𝐧𝐬𝐑𝐚𝐭𝐢𝐨
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Presentation Outline
Transformer Purpose What Does a Transformer Do? How Does it Work?
Electrical Design Characteristics Transformer Losses Efficiency & Impedance Example Design
Design Considerations and Flexibility Core Type Winding Material Winding Connections System Connection Transformer Configuration Tank Material
Product Requirement Considerations Cooling Methods Monitoring Devices Protection Devices
Application Considerations Functional Examples
Loss Evaluation
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Electrical Design Characteristics
Design Parameters:
Number of Phases (1 vs 3)
Power Rating (kVA)
High Voltage (V)
HV BIL (kV)
Low Voltage (V)
LV BIL (kV)
Frequency (Hz)
Temperature Rise (Deg C)
Design Optimization Features:
Transformer Losses
Efficiency
Impedance
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Transformer No-Load and Load LossesIron and Copper Losses
No-load losses are caused by the alternating magnetization of the core (hysteresis losses) and by eddy-currents in the core – They occur as soon as a transformer is energized
Load losses are caused by the losses in the conductors (resistive and eddy current). They have a quadratic dependence on the load factor
DOE estimated average load of the utility distribution transformers is only 50%…
Canada: study* on weighted average load of LV dry-type distribution transformer : (office, manufacturing, health care, school, retail): 15.9%
Reduction of no-load loss has major focus
* Office of Energy Efficiency, Canada: “Metered load factors for LV, dry-type transformers in commercial, industrial and public buildings”, Nov. 2008
400 kVA BkBo distribution transformer
no-load loss
load loss
total loss
0500
1'0001'5002'000
2'5003'0003'5004'0004'500
0% 20% 40% 60% 80% 100%load
loss
(W)
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Efficiency & Impedance
Efficiency Desired output / required input
Lower losses = higher efficiency (and vice versa)
Very high (typically greater than 98%)
Minimum standards set by DOE, CSA
Impedance Function of resistance and reactance of windings
Manipulated to control short circuit current, voltage regulation, load balance under parallel operation
Recommended tolerances provided by IEEE
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Example Distribution Transformer Design:
Number of Phases: 3 - Phase Power Rating: 750 kVA High Voltage: 12470 V (Delta) Low Voltage: 480 / 277 V (Grounded Wye) Frequency: 60 Hz Temp. Rise (liquid): 65 Deg C Temp. Rise (dry): 150 Deg C
Efficiency: 99.32% Impedance: 5.76% Load Loss: 6786 W No Load Loss: 967 W
Ref: JC61384
© ABBSlide 21May 3, 2023
Presentation Outline
Transformer Purpose What Does a Transformer Do? How Does it Work?
Electrical Design Characteristics Transformer Losses Efficiency & Impedance Example Design
Design Considerations and Flexibility Core Type Winding Material Winding Connections System Connection Transformer Configuration Tank Material
Product Requirement Considerations Cooling Methods Monitoring Devices Protection Devices
Application Considerations Functional Examples
Loss Evaluation
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Design Considerations & Flexibility
Core Type Wound Core
Stacked Core
Winding Material Winding Connections
System Connection Transformer Configuration
Radial Feed
Loop Feed
Tank Material
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Single Phase:
Jeff City units manufactured as Shell Form Core is unwound on short end, slid onto the coil, and rewound around coil
Core Type – Wound Core
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Single Phase Shell Form
Can be wound as Lo-Hi-Lo (shown to the right) or Lo-Hi.
Lo-Hi-Lo typically has lower impedance and lower regulation than a similar Lo-Hi.
Core Type – Wound Core
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Three Phase Construction – Five Legged Wound Core
Same process as single phase with two extra cores to attach around the coils
Provides a return path for the magnetic flux – necessary for grounded wye connections
Core Type – Wound Core
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Core Type – Stacked CoreThree Phase Construction – Stacked & Wound Core Options
Only wound core option is five legged
Stacked core options provided as three or four legged
Core leg used as mandrel and coils are wound onto the core leg (WOCL)
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Core Type – Stacked Core
Coils are installed over “E” (stacked core without top yoke)
Top yoke stacked after coils are wedged in place
Mechanical members are installed
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ABB uses one core technology for all Dry Transformers
Stacked core Allows for simple installation of coils Automated cutting lines result in good
fabrication Assembly of limbs and yokes can be time-
consuming
Step-lap joints Good flux distribution at joints resulting in
lower no-load losses
Thin grain-oriented electrical steels Lower hysteresis and eddy losses Many pieces to handle during assembly
Single or multi-step cross-section profile Accepts round, oval, or rectangular coils Optimization of steel widths and stack
height needed to maximize filling of the core circle
Core Type – Stacked Core
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Winding Material
Copper Tight size requirements
Salt spray environments
Tough efficiency requirements
Aluminum Light weight requirements
Typically less expensive
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Winding Connections – Single Phase
Single Phase – 1 coil
Must bank / connect 3 single phase units to obtain alternate voltages
Common HV connection terminology:
Delta
Wye
Grounded Wye
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Winding Connections – Single Phase
LV typically connected in 2-wire or 3-wire configuration
3-wire tapped at midpoint of windings for optional voltage
4-wire connection available
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Winding Connections – Three Phase
Depends on system configuration
Number of service wires
Grounded vs. ungrounded sources
Impedance matching when banking
Desired phase shift
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Delta – Grounded Wye
Delta – Delta
Grounded Wye – Grounded Wye
Wye – Delta
AVOID Grounded Wye – Delta
Subject to primary grounding duty
Dry-type units (Bland) grounded by customer
Liquid filled distribution units (Jeff City) grounded by manufacturer
Winding Connections – Three Phase
Phasor Diagrams
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System Connection – Live vs. Dead Front Live Front:
Non-insulated
HV porcelain bushings
LV spades
For bus bar, close couple, etc.
Dead Front: Insulated
Molded epoxy / rubber
Bushing wells and inserts
For load-break elbow connection
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Configuration – Radial Feed
The last transformer before the end user One incoming HV line per phase, no outgoing HV lines “End of the line” i.e. electricity is not fed through
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Configuration – Loop Feed
Continues the feed of power through the grid One incoming HV line per phase, one outgoing HV line per phase
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System ConnectionDry-type transformers
Bus coordinated to close-coupled switchgear Cable In/Out
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Tank Material
Mild Steel Less expensive
Ease of manufacturability
Stainless Steel Corrosion resistance
Non-magnetic
Strength, hardness, longevity
More expensive
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Enclosure Construction
NEMA 1 (Indoor) Least expensive
Protection from small animals
NEMA 3R (Outdoor) Protection from rain and deflected splash from all
directions
Protection from snow
Dry-type Submersible (similar tank to liquid filled) Maintenance free
Arc-flash resistant
More expensive
© ABBSlide 40May 3, 2023
Presentation Outline
Transformer Purpose What Does a Transformer Do? How Does it Work?
Electrical Design Characteristics Transformer Losses Efficiency & Impedance Example Design
Design Considerations and Flexibility Core Type Winding Material Winding Connections System Connection Transformer Configuration Tank Material
Product Requirement Considerations Cooling Methods Monitoring Devices Protection Devices
Application Considerations Functional Examples
Loss Evaluation
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Product Requirement Considerations
Cooling Methods Insulating Fluid
Forced Cooling
Monitoring Devices Protection Devices
Fuses
Switches
Lightning Arresters
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Insulating Fluid
Air = Dry type transformer
Oil = Liquid filled transformer
Factors to consider: Environment
Application
Loading profile
Temperature rise constraints
* Temp. rise does not affect HVAC requirements for indoor applications
*
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Forced Cooling
Radiator banks Bolted/welded fins allow for enhanced
heat exchange with external environment
Greater surface area of fins = higher cooling effect
Decreases losses, increases efficiency
Fans Forces air through radiators to provide
additional cooling
Usually tripped by oil temp / winding temp alarm contacts at preset temperature thresholds
Only provided on substation type transformers
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Dry-type Cooling
Fans / blowers Typically controlled with optional winding
temperature monitor
FA rating – up to 50% increase
Indirect hydro-cooling Non-ventilated enclosure (i.e. closed
cooling system)
Keeps transformer protected against contaminated environments
Rating increase up to 25%
© ABBSlide 45May 3, 2023
Monitoring Devices
Various gauges monitor critical operational factors
Liquid level
Oil temperature
Winding temperature
Internal tank pressure
Optional alarm contacts to trip relays, external breakers, alert SCADA systems, etc.
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Protection Devices Fuses
Protects system in the event of transformer winding failure
Can prevent line crews from re-energizing a faulted transformer
Single or double fusing schemes
Expulsion fuses with isolation links
Expulsion fuses with partial range current limiting fuses
Switches Allows isolation of incoming or outgoing lines
On/off switch provides control of transformer usage
© ABBSlide 47May 3, 2023
Protection Devices
Arresters Protects transformer in case of high voltage
surge due to lightning strike, voltage inrush from system, etc.
Routes voltage surge to ground
Metal Oxide Varistor Elbow arresters (dead front)
Distribution Class arresters (live front)
© ABBSlide 48May 3, 2023
Presentation Outline
Transformer Purpose What Does a Transformer Do? How Does it Work?
Electrical Design Characteristics Transformer Losses Efficiency & Impedance Example Design
Design Considerations and Flexibility Core Type Winding Material Winding Connections System Connection Transformer Configuration Tank Material
Product Requirement Considerations Cooling Methods Monitoring Devices Protection Devices
Application Considerations Functional Examples
Loss Evaluation
© ABBSlide 49May 3, 2023
Application Considerations
Transformer Location Indoor vs. outdoor
Proximity to buildings / people
Accessible to public vs. enclosed in secure room
Main Customer Residential vs. commercial
Rural vs. urban environment
Utility service vs. industrial project
Loading Conditions Continuous vs. intermittent
System peak vs. transformer peak
© ABBSlide 50May 3, 2023
11000 VOLTSGENERATED
POWER HOUSEVOLTAGE INCREASES
NETWORK FAULT
66000 VOLT TRANSMISSION
SUB-STATION FROMTRANSMISSION LINE
INDUSTRIAL CUSTOMER
1st VOLTAGE REDUCTION(TRANSMISSIONSUBSTATION)
4000 VOLT DISTRIBUTION
2nd VOLT REDUCTION(DISTRIBUTIONSUBSTATION)
POWER CENTERINDUSTRIAL PLANT
22000 VOLTS LOW VOLTAGE TRANSMISSION
SUB-STATION FROMLOW VOLTAGE TRANSMISSION
Electrical Service From The Generator To The Customer
SUBWAY VAULT
COMMERCIALCUSTOMER
15
DISTRIBUTIONTRANSFORMER
RESIDENTIALCUSTOMER
120/240VOLTS
GenerationTransmission
Distribution
© ABBSlide 51May 3, 2023
Functional ExamplesDry-type Primary Substation Transformers
69kV Indoor transmission substation (above)
25MVA 69kV – 13.8kV
46kV Outdoor transmission substation (right)
4MVA 46kV – 4160V
© ABBSlide 52May 3, 2023
Functional ExamplesDry-type Distribution Transformers
15kV Outdoor distribution substation
2500kVA
15kV – 480V
15kV Indoor distribution substation
3000kVA
15kV – 480V
15kV Subway type submersible network
500kVA
15kV – 480V
© ABBSlide 53May 3, 2023
Functional ExamplesLiquid Filled Secondary Unit Substation Transformers
34.5kV Outdoor distribution substation 3000 KVA 34.5kV – 2400V
© ABBSlide 54May 3, 2023
Functional ExamplesLiquid Filled Padmount Distribution Transformers
27.6kV Outdoor 3PH padmount transformer (top left)
500 KVA 27.6kV – 480V
12.47kV Outdoor 1PH padmount transformer (bottom right)
100 KVA 12.47kV – 240V
© ABBSlide 55May 3, 2023
Functional ExamplesPolemount / Submersible Distribution Transformers
2400V Outdoor 1PH polemount transformer (top left)
50 KVA 2400V – 240V
24.94kV 1PH submersible / vault transformer (top right)
167 KVA 24.94kV – 600V
14.4kV 3PH submersible / vault transformer (bottom left)
1000 KVA 14.4kV – 480V
© ABBSlide 56May 3, 2023
Application Considerations
Protected industrial environment Data centers, Utility spot networks, rail, food & bev, office
buildings, hospitals
Environmental contamination Metals, power generation (e.g. coal fired), Offshore O&G, Utility
spot networks
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Application Considerations
Shock/vibration and cold climates
Offshore O&G, Mobile equipment (e.g. cranes, etc.), Pipelines (critical power and compressor stations)
Public distribution and power projects Utility networks, housing developments, commercial buildings,
high volume public power providers
© ABBSlide 58May 3, 2023
Presentation Outline
Transformer Purpose What Does a Transformer Do? How Does it Work?
Electrical Design Characteristics Transformer Losses Efficiency & Impedance Example Design
Design Considerations and Flexibility Core Type Winding Material Winding Connections System Connection Transformer Configuration Tank Material
Product Requirement Considerations Cooling Methods Monitoring Devices Protection Devices
Application Considerations Functional Examples
Loss Evaluation
© ABBSlide 59May 3, 2023
Loss Evaluation Cost of Losses = Cost of No Load Loss + Cost of Load Loss
Costs associated with: Power generation
Purchasing of power
Loading practice (system peak vs. transformer peak)
Average transformer life
Interest rate (cost of money)
All of these are used to calculate the A and B factors A factor – No Load Loss
B factor – Load Loss
© ABBSlide 60May 3, 2023
Loss Evaluation Total Ownership Cost (TOC) = Initial Transformer Price + Cost of Losses TOC = Price + (A x No Load Loss) + (B x Load Loss)
Loss
Cos
t Cost ofLosses
TransformerCost
© ABBSlide 61May 3, 2023
Questions?
© ABBSlide 62May 3, 2023
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© ABBSlide 63May 3, 2023
Contact information
If you have further questions , please refer to our contact information below:
Chris Morrow Kevin Liu
ABB - Jefferson City, MO ABB - Bland, VA
+1 (573) 659 6341 +1 (276) 688 1545