Download Eaton Presentation from May 2014

Article 450 - Transformers
Thomas A. Domitrovich, P.E.
National Application Engineer
LEED® Accredited Professional
Eaton Corporation Electrical Group
1000 Cherrington Parkway
Moon Township, PA 15108
Cell: 412-716-1475
email: [email protected]
Tim McBride, P.E.
Application Engineer
©  2008 Eaton Corporation. All rights reserved.
The Transformer
An electrical device that
transfers energy by magnetic
induction from one circuit to
another.
Usually the voltage and current
are transformed from one level
to another.
2
2
The Transformer – Basic Components
Dry-Type Transformer Example
•  Primary & Secondary
Windings
•  Core
•  Frame
•  Enclosure
•  Ventilation
3
3
Transformer Types – Sampling
•  Step – Up
•  Step – Down
•  Autotransformer
•  Isolation Transformer
•  Single – Phase
•  Polyphase
•  Harmonic Transformers
•  Instrument Transformers
4
4
Transformer Locations / Applications
•  Utility Supply To Facilities
•  Commercial, Industrial, Residential and More
•  Power Distribution Equipment
•  Switchgear, Switchboards
•  Utilization Equipment Control Power
•  Motor Control Centers, Industrial Control Panels
•  Instrumentation Applications
•  Metering and Relaying
5
5
Utility
G
OC
PD
OC
PD
OC
PD
OC
PD
OC
PD
OC
PD
VT
OC
PD
CT
OC
PD
M
M
OC
PD
Industrial
Control
Panel
OC
PD
OC
PD
OC
PD
OC
PD
M
OC
PD
OC
PD
6
6
Utility
G
OC
PD
OC
PD
•  Main Incoming Utility
Transformer
OC
PD
OC
PD
OC
PD
OC
PD
VT
OC
PD
CT
OC
PD
M
M
OC
PD
Industrial
Control
Panel
OC
PD
OC
PD
OC
PD
OC
PD
M
OC
PD
OC
PD
7
7
Utility
G
OC
PD
OC
PD
Instrumentation
Transformers
OC
PD
OC
PD
OC
PD
OC
PD
VT
OC
PD
CT
OC
PD
M
M
OC
PD
Industrial
Control
Panel
OC
PD
OC
PD
OC
PD
OC
PD
M
OC
PD
OC
PD
8
8
Utility
G
OC
PD
OC
PD
Power Distribution
Transformers
OC
PD
OC
PD
OC
PD
OC
PD
VT
OC
PD
CT
OC
PD
M
M
OC
PD
Industrial
Control
Panel
OC
PD
OC
PD
OC
PD
OC
PD
M
OC
PD
OC
PD
9
9
Utility
G
OC
PD
OC
PD
Control Power
Transformers
OC
PD
OC
PD
OC
PD
OC
PD
VT
OC
PD
CT
OC
PD
M
M
OC
PD
Industrial
Control
Panel
OC
PD
OC
PD
OC
PD
OC
PD
M
OC
PD
OC
PD
10
10
Utility
G
OC
PD
OC
PD
Transformers Are A Very Important Part of
The Power Distribution System
OC
PD
OC
PD
OC
PD
OC
PD
VT
OC
PD
CT
OC
PD
M
M
OC
PD
Industrial
Control
Panel
OC
PD
OC
PD
OC
PD
OC
PD
M
OC
PD
OC
PD
11
11
Transformer Basics
©  2008 Eaton Corporation. All rights reserved.
•  3-Phase Transformers
•  Incorporate three sets of windings
•  Can be wired Delta or Y on primary or secondary
•  Can be grounded or ungrounded
•  1-Phase Transformers
13
13
Three Phase Delta-Wye
Vll = VΦ
14
Vll - √ 3*VΦ
14
VΦ
14
Basic Transformer Principle
● 
A voltage and current in the primary coil magnetize the iron core.
● 
The magnetic field in the core induces a voltage and current in the secondary coil.
CORE
Enclosure
Primary
Secondary
windings
windings
15
15
Transformer Example
Primary
Core
Secondary
V1
N1
=
V1 =
480 volts
V2 =
120 volts
V2
N2
A2
N1
=
N2 = 100
N1 = 400
A1
N2
V1
A2
=
A1 =
52 amps
N1 - # turns (primary)
A2 =
V2
208 amps
V1-primary voltage
N2 - # turns (secondary) V2-secondary voltage
A1
A1-primary current
A2-secondary current
16
16
KVA
KVA is the transformer’s capacity or load
that it can handle.
Three Phase
Single Phase
KVA = Volts * Amps
1000
KVA =
3*VoltsØ * AmpsØ
1000
-orKVA = VoltsL * AmpsL * 1.732
1000
17
17
17
KVA Example
Customer’s load - three phase, 480 volts, 60 Hz, 100 amps
KVA = Volts * Amps * 1.732
1000
KVA =
480
X
100
X
1.732
1000
KVA = 83.14
18
18
18
FLA & Isc Example
Full Load Amps - three phase, 480 volts, 60 Hz, 300 kVA
Amps = 1000* kVA
1.732 *Volts
Amps =
300 X 1000
480
X 1.732
Amps = 361 A
Isc = FLA
%Z
19
=
361 = 6278 A
.0575
19
19
Taps
•  Correct for high or low input voltage conditions
so the transformer will still provide its rated
output voltage
•  Connection off of the primary winding
•  Usually in 2.5% or 5.0% increments
•  FCAN - Full Capacity Above Nominal
•  FCBN - Full Capacity Below Nominal
20
20
20
Taps
Correct for high or low input voltage conditions
so that transformer will still provide its rated
output voltage.
Connection off the primary winding,
usually in 2.5% or 5.0% increments.
FCAN - Full Capacity Above Nominal
FCBN - Full Capacity Below Nominal
21
21
21
Taps Example
+ 2 @ 2-1/2% FCAN
- 4 @ 2-1/2% FCBN
480V
120V
22
22
22
Tap Example – Low Primary V
Change The Turns Ratio
4
1
480
120
Primary
Secondary
480V
120V
432
108
4
1
432
3.6
1
120
23
23
23
Insulation Systems and
Temperature Rise
Temperature Rise
55
80
115
150
Hot Spot
10
30
30
30
Ambient
40
40
40
40
105
150
185
220
A
B
F
H
Insulation Class/
Limiting Temperature
Former Designation
Temperatures in degrees centigrade
24
24
24
Auxiliary Cooling
•  Liquid filled transformers
Fan cooling - 15%
750 kVA to 2000 kVA
Fan cooling - 25%
2500 kVA and above
•  Dry type transformers
Fan cooling - 33%
25
All ratings
25
25
Ratings - Liquid Filled
`Fluid Filled
65°C Rise
26
OA
(Base
Rating)
FA
(OA x 1.15
<2500 kVA,
OA x 1.25
2500kVA & >)
300
500
750
1000
1500
2000
2500
----862
1150
1725
2300
3125
55/65°C Rise
OA
55°C
OA 65°C
OA x 1.12
(Base
Rating)
300
500
750
1000
1500
2000
2500
336
560
840
1120
1580
2240
2800
FA 55°C
(OA x 1.15
FA 65°C
<2500 kVA,
OA x 1.25
2500kVA & >)
OA 65C x 1.15
<2500 kVA,
OA 65C x 1.25
2500kVA & >
----862
1150
1725
2300
3125
----966
1288
1932
2576
3500
26
26
Ratings - Cast Coil
100°C Rise
27
80/100°C Rise
AA 100
(Base)
FA
(AA100 x
1.33)
AA 80
(Base)
AA 100
(AA80 x
1.125)
FA 100
(AA100 X
1.33)
300
500
750
1000
1500
2000
2500
--667
1000
1333
2000
2667
3333
300
500
750
1000
1500
2000
2500
338
563
844
1125
1688
2250
2813
--750
1125
1500
2250
3000
3750
27
27
Ratings - Dry Type
150°C Rise
115/150°C Rise
AA
150C
(Base)
FA
(AA150 x
1.33)
AA
115°C
(Base)
AA 150°C
(AA115 x
1.15)
FA 150°C
(AA150 x 1.33)
300
500
750
1000
1500
2000
2500
400
667
1000
1333
2000
2667
3333
300
500
750
1000
1500
2000
2500
345
575
863
1150
1725
2300
2875
460
767
1151
1533
2300
3067
3833
80/115°C Rise
28
AA
80°
(Base)
AA
115°
(AA80 x 1.18)
300
500
750
1000
1500
2000
2500
354
590
885
1180
1770
2360
2950
80/150°C Rise
FA
115°
(AA115 x
1.33)
AA
80°C
(Base)
AA
150°C
(AA80 x
1.35)
FA
150°C
(AA150
x 1.33)
472
787
1180
1573
2360
3147
3933
300
500
750
1000
1500
2000
2500
405
675
1013
1350
2025
2700
3375
540
900
1351
1800
2700
3600
4500
28
28
Insulation Levels
Kv BIL
High
Voltage
Rating
2400
4160
4800
6900
7200
12000
12470
13200
13800
22,900
34,400
29
Liquid
Filled
Transf.
HV
45
60
60
75
75
95
95
95
95
125
150
Liquid
Filled
Transf.
LV
(600 Max).
Vent. Dry
Transf.
HV
Vent. Dry
Transf.
LV
(600 Max.)
Cast Coil
Transf.
HV
Cast Coil
Transf.
LV
(600 Max.)
30
30
30
30
30
30
30
30
30
30
30
30
30
30
40
40
60
60
60
60
110
150
10
10
10
10
10
10
10
10
10
10
10
45
60
60
75
75
95
95
95
95
110
150
10
10
10
10
10
10
10
10
10
10
10
29
29
Sound Levels
Table 6 - NEMA TR-1 Maximum Sound Level Comparison USTs
Liquid-Types
Dry-Types
kVA
(All Fluids)
VPI,VPE,CAST
OA
OA/FA
AA
AA/FA
301 to 500
56
67
60
67
501 to 700
57
67
62
67
701 to 1000
58
67
64
67
1001 to 1500
60
67
65
68
1501 to 2000
61
67
66
69
2001 to 2500
62
67
68
71
2501 to 3000
63
67
68
71
30
30
30
Transformer Standards
©  2008 Eaton Corporation. All rights reserved.
Transformer Standards
UL 506
“Specialty Transformers”
UL 1561 “Dry-Type General Purpose and Power Transformers”
UL 1562 ‘‘Transformers, Distribution, Dry-Type – Over 600 Volts,’’
UL 2161 “Neon Transformers and Power Supplies”
32
32
Transformer Standards
UL 506
“Specialty Transformers”
1.1 These requirements cover ignition transformers for use with gas
burners and oil burners and specialty step-up transformers used in
applications such as insect electrocuting. Transformers incorporating
overcurrent or over-temperature protective devices, transient voltage surge
protectors, or power factor correction capacitors are also covered by these
requirements. These transformers are intended to be used in accordance
with the National Electrical Code, NFPA 70.
33
33
Transformer Standards
UL 1561 “Dry-Type General Purpose and Power Transformers”
These requirements cover:
a) General purpose and power transformers of the air-cooled, dry,
ventilated, and non-ventilated types to be used in accordance with the
National Electrical Code, ANSI/NFPA 70. Constructions include step up,
step down, insulating, and autotransformer type transformers as well as aircooled and dry-type reactors or
b) General purpose and power transformers of the exposed core, aircooled, dry, and compound-filled types rated more than 10 kVA to be used
in accordance with the National Electrical Code, ANSI/NFPA 70.
Constructions include step up, step down, insulating, and autotransformer
type transformers as well as air-cooled, dry, and compound-filled type
reactors.
34
34
Transformer Standards
UL 1562 ‘‘Transformers, Distribution, Dry-Type – Over 600 Volts,’’
1.1 These requirements cover single-phase or three-phase, dry-type,
distribution transformers, including solid cast and resin encapsulated
transformers. The transformers are provided with either ventilated or nonventilated enclosures and are rated for a primary or secondary voltage from
601 to 35000 V.
35
35
Transformer Standards
UL 2161
“Neon Transformers and Power Supplies”
1.1 This standard applies to transformers and power supplies, including those intended to be
connected to a Class 2 source of supply, that provide the voltage and ballasting for neon and
cold-cathode tubing (electric-discharge tubing) consisting of electrodes and gas such as neon,
mercury, helium, argon, and similar gases, enclosed in glass. Neon transformers and power
supplies for use in signs and outline lighting are intended to be used in accordance with Article
600 of the National Electrical Code, NFPA 70. Cold-cathode supplies identified for use only in
cold-cathode lighting systems are intended to be used in accordance with Article 410 of the
National Electrical Code.
1.2 Neon transformers and power supplies covered by this standard are designated by their
construction and intended use as specified in Table 1.1.
36
36
Transformer Standards
UL 2161
“Neon Transformers and Power Supplies”
37
37
Transformers and The NEC
©  2008 Eaton Corporation. All rights reserved.
Transformers and The NEC
•  Article 450 “Transformers and
Transformer Vaults (Including
Secondary Ties)”
•  450.1 Scope. This article covers
the installation of all transformers.
The NEC Has An Entire Article, Article 450, Dedicated To Transformers
39
39
Transformers and The NEC
450.1 Scope. This article
covers the installation of all
transformers.
Exceptions
1.  Current transformers.
2.  Dry-type transformers that constitute a component part
of other apparatus and comply with the requirements for
such apparatus.
3.  Transformers that are an integral part of an X-ray, highfrequency, or electrostatic-coating apparatus.
4.  Transformers used with Class 2 and Class 3 circuits that
comply with Article 725.
5.  Transformers for sign and outline lighting that comply
with Article 600.
Exceptions Illustrate Other Articles
Important to Proper Application of
Transformers
6.  Transformers for electric-discharge lighting that comply
with Article 410.
7.  Transformers used for power-limited fire alarm circuits
that comply with Part III of Article 760.
8.  Transformers used for research, development, or
testing, where effective arrangements are provided to
safeguard persons from contacting energized parts.
Don’t Stop At Article 450
Understand The Application
40
40
Transformers and The NEC
Article 725: Class 1, Class 2, and Class 3
Remote – Control, Signaling, and Power-Limited
Circuits
450.1 Scope. This article
covers the installation of all
Article 600: Electric Signs and Outline Lighting
transformers.
Article 410: Luminaires, Lampholders, and
Lamps
Article 760: Fire Alarm Systems
Exceptions
1.  Current transformers.
2.  Dry-type transformers that constitute a component part
of other apparatus and comply with the requirements for
such apparatus.
3.  Transformers that are an integral part of an X-ray, highfrequency, or electrostatic-coating apparatus.
4.  Transformers used with Class 2 and Class 3 circuits that
comply with Article 725.
5.  Transformers for sign and outline lighting that comply
with Article 600.
Exceptions Illustrate Other Articles
Important to Proper Application of
Transformers
6.  Transformers for electric-discharge lighting that comply
with Article 410.
7.  Transformers used for power-limited fire alarm circuits
that comply with Part III of Article 760.
8.  Transformers used for research, development, or
testing, where effective arrangements are provided to
safeguard persons from contacting energized parts.
Don’t Stop At Article 450
Understand The Application
41
41
Protection – Table 450.3(A)
PRIMARY OVER 1000 VOLTS
Any Location
IMPEDANCE
Not More Than 6%
PRIMARY PROTECTION
600% - Circuit Breaker
300% - Fuse
Seconday > 1000Volts
300% - Circuit Breaker
250% - Fuse
Seconday 1000Volts or Less
125% - Circuit Breaker
42
125% - Fuse
42
42
Protection – Table 450.3(A)
PRIMARY OVER 1000 VOLTS
Any Location
IMPEDANCE
More Than 6% & Not More Than10%
PRIMARY PROTECTION
400% - Circuit Breaker
300% - Fuse
Seconday > 1000Volts
250% - Circuit Breaker
225% - Fuse
Seconday 1000Volts or Less
125% - Circuit Breaker
43
125% - Fuse
43
43
Protection – Table 450.3(A)
PRIMARY OVER 1000 VOLTS
Supervised Location
IMPEDANCE
Not More Than 6%
PRIMARY PROTECTION
600% - Circuit Breaker
300% - Fuse
Seconday > 1000Volts
300% - Circuit Breaker
250% - Fuse
Seconday 1000Volts or Less
250% - Circuit Breaker
44
250% - Fuse
44
44
Protection – Table 450.3(A)
PRIMARY OVER 1000 VOLTS
Supervised Location
IMPEDANCE
More Than 6% & Not More Than10%
PRIMARY PROTECTION
400% - Circuit Breaker
300% - Fuse
Seconday > 1000Volts
250% - Circuit Breaker
225% - Fuse
Seconday 1000Volts or Less
250% - Circuit Breaker
45
250% - Fuse
45
45
Protection – Table 450.3(A)
PRIMARY OVER 1000 VOLTS
Supervised Location
IMPEDANCE
Any
PRIMARY PROTECTION
300% - Circuit Breaker
250% - Fuse
Seconday > 1000Volts
N/A - Circuit Breaker
N/A - Fuse
Seconday 1000Volts or Less
N/A - Circuit Breaker
46
N/A - Fuse
46
46
Protection – Table 450.3(A)
Next Standard Rating
6 Disconnect Rule – Single Location
Total Rating Not to Exceed Allowed
Value of Single Over Current Device
47
47
47
Protection – Table 450.3(B)
PRIMARY 1000 VOLTS & LESS
PRIMARY PROTECTION ONLY
48
Currents of 9 Amps or More
125%
Currents Less Than 9 Amps
167%
Currents Less Than 2 Amps
300%
48
48
Protection – Table 450.3(B)
PRIMARY 1000 VOLTS & LESS
PRIMARY
PROTECTION
SECONDARY
PROTECTION
Currents of 9 Amps or More
250%
125%
Currents Less Than 9 Amps
250%
167%
Currents Less Than 2 Amps
250%
--
49
49
49
Protection – Table 450.3(B)
Next Standard Rating
6 Disconnect Rule – Single Location
Total Rating Not to Exceed Allowed
50
50
50
Protection – Table 450.10 (A) & (B)
450.10 Grounding
(A) Dry-Type Transformer Enclosures. Where separate equipment grounding
conductors and supply-side bonding jumpers are installed, a terminal bar
for all grounding and bonding conductor connections shall be secured
inside the transformer enclosure. The terminal bar shall be bonded to the
enclosure in accordance with 250.12 and shall not be installed on or over
any vented portion of the enclosure.
Exception: Where a dry-type transformer is equipped with wire-type
connections (leads), the grounding and bonding connections shall be
permitted to be connected together using any of the methods in 250.8 and
shall be bonded to the enclosure if of metal.
(B) Other Metal Parts
51
51
51
Protection – Table 450.10 (A) & (B)
450.11 Markings
(A) General
(1) Name of Manufacturer
(2) Rated Kilovolt-Amperes
(3) Frequency
(4) Primary and Secondary Voltage
(5) Impedance of Transformers 25 kVA and Larger
(6) Required Clearance for Transformers with Ventilated Openings
(7) Amount and Kind of Insulating Liquid Where Used
(8) For Dry-Type Transformers, Temperature Class for the
Insulation System
52
52
52
Transformer Standards
Using Listed Products Provides A Level of Assurance That
The Product Will Perform As Expected
53
53
Transformers and The NEC
•  Other NEC Articles Important To Transformer
Applications
•  Article 312 “Cabinets, Cutout Boxes, and Meter Socket Enclosures”
•  Article 426 “Fixed Outdoor Electric Deicing and Snow-Melting
Equipment”
•  Article 427 “Fixed Electric Heating Equipment for Pipelines and
Vessels”
•  Article 430 “Motors, Motor Circuits, and Controllers”
•  Article 501 “Class I Locations”
•  Article 502 “Class II Locations”
•  Article 503 “Class III Locations”
•  Article 680 “Swimming Pools, Fountains, and Similar Installations”
54
54
Questions And Comments
©  2008 Eaton Corporation. All rights reserved.
56
56
The Transformer – Basic Components
57
57
•  General Provisions
•  Overcurrent Protection
•  Transformers over 1000 Volts
•  Transformers 1000 Volts Nominal or Less
•  Autotransformers
•  Standard
•  Grounding Transformers
•  Grounding
•  Markings
58
58
Three- Core Construction
Wound Cores
Stacked Cores
59
59
Coil Construction
LV Sheet Winding with Cold Welded Lead
60
60
Coil Construction
LV Sheet Winding with Cold Welded Lead
Finished Coil
HV Winding with Diamond Epoxy Insulation
Complete Core & Coil Assembly
61
61
Coil Construction
LV Sheet Winding with Cold Welded Lead
Finished Coil
HV Winding with Diamond Epoxy Insulation
Complete Core & Coil Assembly
62
62
Coil Construction
LV Sheet Winding with Cold Welded Lead
Finished Coil
HV Winding with Diamond Epoxy Insulation
Complete Core & Coil Assembly
63
63
Serving Many Locations
64
64 64
Open Type Transformer
•  Open Type Transformer for
Utility Applications:
•  Investor Owned
•  Public Power
•  Municipal
•  REA
•  CO-OP
65
65
Unit Substation Transformer
•  Unit Substation Transformer for
Industrial/Commercial
Applications:
•  Petro/Chem
•  Pulp & Paper
•  Government/Military
•  Institutional
•  Food & Drug
•  Mining & Minerals
•  Manufacturing
•  Data Centers
66
66
67
67
The Transformer – Codes and Standards
PJXS – Metering Transformer Cabinets
PWIK – Neon Transformers and Power Supplies
WDGV – Swimming Pool and Spa Transformers
XNWX – Transformers
XOBA, XOKV, XOYT,
XPFS, XPLH, XPTQ,
XPZZ, XQNX, XRBV
XPAF – Transformers in Hazardous Locations
XPJF, XPLP
68
68
The Transformer – Codes and Standards
PJXS – Metering Transformer Cabinets
Article 312 Cabinets, Cutout Boxes, and Meter Socket Enclosures
Sections 312.1 & 312.5
PWIK – Neon Transformers and Power Supplies
Article 600 “Electric Signs and Outline Lighting”
WDGV – Swimming Pool and Spa Transformers
XNWX – Transformers
XOBA, XOKV, XOYT,
XPFS, XPLH, XPTQ,
XPZZ, XQNX, XRBV
69
69
The Transformer – Codes and Standards
70
70
•  Specific Provisions Applicable to Different Types of
Transformers
•  Dry types
•  indoors
•  Outdoors
•  Liquid-insulated
•  Indoors
•  Outdoors
•  Other types of insulated transformers
71
71
•  Transformer Vaults
•  Location
•  Construction
•  Ventilation
•  Drainage
•  Storage
72
72