[James_H._Harlow]_Electric_Power_Transformer_Engin(BookSee.org)

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TABLE 3.14.4 NEMA TP-2 Rating Range for Single-Phase and Three-Phase Dry-Type and Liquid-Immersed Distribution Transformers Transformer Type Number of Phases Rating Range Liquid immersed Single phase 10–833 kVA Three phase 15–2500 kVA Dry type Single phase 15–833 kVA Three phase 15–2500 kVA Note: Includes all products at 1.2 kV and below. 3.14.3.3.3 NEMA TP-2, Standard Test Method for Measuring the Energy Consumption of Distribution Transformers This standard is intended for use as a basis for determining the energy-efficiency performance of the equipment covered and to assist in the proper selection of such equipment. This standard covers singlephase and three-phase dry-type and liquid-immersed distribution transformers (transformers for transferring electrical energy from a primary distribution circuit to a secondary distribution circuit or within a secondary distribution circuit) as defined in Table 3.14.4. This standard addresses the test procedures for determining the efficiency performance of the transformers covered in NEMA Publication TP-1. Products excepted from this standard include: Liquid-filled transformers below 10 kVA Dry-type transformers below 15 kVA Transformers connected to converter circuits All rectifier transformers and transformers designed for high harmonics Autotransformers Nondistribution transformers, such as UPS transformers Special impedance and harmonic transformers Regulating transformers Sealed and nonventilated transformers Retrofit transformers Machine-tool transformers Welding transformers Transformers with tap ranges greater than 15% Transformers with frequency other than 60 Hz Grounding transformers Testing transformers 3.14.3.3.4 ANSI/UL 1561, Standard for Safety for Dry-Type General-Purpose and Power Transformers These requirements cover: General-purpose and power transformers of the air-cooled, dry, ventilated, and nonventilated types rated no more than 500-kVA single phase or no more than 1500-kVA three phase to be used in accordance with the National Electrical Code, NFPA 70. Constructions include step-up, step-down, insulating, and autotransformer-type transformers as well as air-cooled and dry-type reactors. General-purpose and power transformers of the exposed core, air-cooled, dry, and compound-filled types rated more than 10 kVA but no more than 333 kVA single phase or no more than 1000 kVA three phase to be used in accordance with the National Electrical Code, NFPA 70. Constructions include step-up, step-down, insulating, and autotransformer-type transformers as well as aircooled, dry-type, and compound-filled-type reactors. These requirements do not cover ballasts for high-intensity-discharge (HID) lamps (metal halide, mercury vapor, and sodium types) or fluorescent lamps, exposed-core transformers, compound-filled transformers, liquid-filled transformers, voltage regulators, general-use or special types of transformers covered in requirements for other electrical equipment, autotransformers forming part of industrial control equipment, motor-starting autotransformers, variable-voltage autotransformers, transformers having a nominal primary or secondary rating of more than 600 V, or overvoltage taps rated greater than 660 V. These requirements do not cover transformers provided with waveshaping or rectifying circuitry. Waveshaping or rectifying circuits may include components such as diodes and transistors. Components such as capacitors, transient-voltage surge suppressors, and surge arresters are not considered to be waveshaping or rectifying devices. A product that contains features, characteristics, components, materials, or systems new or different from those in use when the standard was developed — and that involves a risk of fire, electric shock, or injury to persons — shall be evaluated using the appropriate additional component and end-product requirements as determined necessary to maintain the level of safety for the user of the product as originally anticipated by the intent of this standard. 3.14.3.3.5 ANSI/UL 1446, Standard for Safety for Systems of Insulating Materials — General These requirements cover test procedures to be used in the evaluation of Class 120(E) or higher electrical insulation systems intended for connection to branch circuits rated 600 V or less. These requirements also cover the investigation of the substitution of minor components of insulation in a previously evaluated insulation system and also the test procedures to be used in the evaluation of magnet wire coatings, magnet wires, and varnishes. These requirements do not cover a single insulating material or a simple combination of materials, such as a laminate or a varnished cloth. These requirements do not cover insulation systems exposed to radiation or operating in oils, refrigerants, soaps, or other media that potentially degrade insulating materials. These requirements shall be modified or supplemented as determined by the applicable requirements in the end-product standard covering the device, appliance, or equipment in which the insulation system is used. Additional consideration shall be given to conducting tests for an insulating material, such as a coil encapsulant, that is used as the ultimate electrical enclosure. Additional consideration shall be given to conducting tests for an insulating material or component that is a functional support of, or in direct contact with, a live part. A product that contains features, characteristics, components, materials, or systems new or different from those in use when the standard was developed — and that involves a risk of fire, electric shock, or injury to persons — shall be evaluated using the appropriate additional component and end-product requirements as determined necessary to maintain the level of safety for the user of the product as originally anticipated by the intent of this standard. 3.14.3.3.6 IEC Technical Committee 14 Power Transformers The purpose of IEC Technical Committee 14 Power Transformers is to prepare international standards for power transformers, on-load tap changers, and reactors without limitation of voltage or power (not including instrument transformers, testing transformers, traction transformers mounted on rolling stock, and welding transformers). Relevant documents are listed in Table 3.14.5. 3.14.3.4 Medium-Voltage and Large-Power Dry-Type Transformers 3.14.3.4.1 IEEE Documents These standards are intended as a basis for the establishment of performance, interchangeability, and safety requirements of equipment described and for assistance in the proper selection of such equipment. Electrical, mechanical, and safety requirements of ventilated, nonventilated, and sealed dry-type distribution and power transformers or autotransformers (single and polyphase, with a voltage of 601 V or higher in the highest-voltage winding) are described. Instrument transformers and rectifier transformers are also included. © 2004 by CRC Press LLC © 2004 by CRC Press LLC
TABLE 3.14.5 Relevant Documents for IEC Technical Committee 14 Power Transformers 60076-1 General requirements 60076-2 Temperature rise 60076-3 Insulation-levels, dielectric tests, and external clearances in air 60076-4 Guide for lightning impulse and switching impulse testing 60076-5 Ability to withstand short circuit 60076-6 Reactors (IEC 289) 60076-8 Power transformers (application guide) 60076-9 Terminal and tapping markings (IEC 616) 60076-10 Determination of transformer reactor sound levels 60076-11 Dry-type power transformers (IEC 726) 60076-12 Loading guide for dry-type power transformers (IEC 905) 61378 Converter transformers 61378-1 Transformers for industrial applications 61378-3 Applications guide The information in these standards apply to all dry-type transformers except as follows: Arc-furnace transformers Rectifier transformers Specialty transformers Mine transformers When these standards are used on a mandatory basis, the word shall indicates mandatory requirements; the words should and may refer to matters that are recommended or permissive but not mandatory. Note: The introduction of this voluntary-consensus standard describes the circumstances under which the standard may be used on a mandatory basis. Relevant IEEE documents are listed in Table 3.14.6. 3.14.3.4.2 NEMA Documents 3.14.3.4.2.1 NEMA TP-1, Guide for Determining Energy Efficiency for Distribution Transformers — This standard is intended for use as a basis for determining the energy-efficiency performance of the equipment covered and to assist in the proper selection of such equipment. This standard covers single-phase and three-phase dry-type and liquid-filled distribution transformers as defined in Table 3.14.7. Products excepted from this standard include: Liquid-filled transformers below 10 kVA Dry-type transformers below 15 kVA Drive transformers, both ac and dc All rectifier transformers and transformers designed for high harmonics Autotransformers Nondistribution transformers, such as UPS transformers Special impedance and harmonic transformers Regulating transformers Sealed and nonventilated transformers Retrofit transformers Machine-tool transformers Welding transformers Transformers with tap ranges greater than 15% Transformers with frequency other than 60 Hz Grounding transformers Testing transformers TABLE 3.14.6 Relevant IEEE Documents IEEE 259-1994 Standard Test Procedure for Evaluation of Systems of Insulation for Specialty Transformers (ANSI) IEEE 638-1992 Standard for Qualification of Class 1E Transformers for Nuclear Generating Stations ANSI C57.12.00-1993 IEEE Standard General Requirements for Liquid-Immersed Distribution, Power, and Regulating Transformers (ANSI) ANSI C57.12.01-1998 IEEE Standard General Requirements for Dry-Type Distribution and Power Transformers Including Those with Solid Cast and/or Resin-Encapsulated Windings IEEE C57.12.35-1996 Standard for Bar Coding for Distribution Transformers ANSI C57.12.40-1994 American National Standard Requirements for Secondary Network Transformers — Subway and Vault Types (Liquid Immersed) IEEE C57.12.44-1994 Standard Requirements for Secondary Network Protectors ANSI C57.12.50-1981 (R1989) American National Standard Requirements for Ventilated Dry-Type Distribution Transformers, 1 to 500 kVA, Single-Phase, and 15 to 500 kVA, Three-Phase, with High-Voltage 601 to 34 500 Volts, Low-Voltage 120 to 600 Volts ANSI C57.12.51-1981 (R1989) American National Standard Requirements for Ventilated Dry-Type Power Transformers, 501 kVA and Larger, Three-Phase, with High-Voltage 601 to 34 500 Volts, Low-Voltage 208Y/120 to 4160 Volts ANSI C57.12.52-1981 (R1989) American National Standard Requirements for Sealed Dry-Type Power Transformers, 501 kVA and Larger, Three-Phase, with High-Voltage 601 to 34 500 Volts, Low- Voltage 208Y/120 to 4160 Volts ANSI C57.12.55-1987 American National Standard for Transformers — Dry-Type Transformers Used in Unit Installations, Including Unit Substations — Conformance Standard IEEE C57.12.56-1986 Standard Test Procedure for Thermal Evaluation of Insulation Systems for Ventilated Dry-Type Power and Distribution Transformers ANSI C57.12.57-1987 (R1992) American National Standard for Transformers — Ventilated Dry-Type Network Transformers 2500 kVA and below, Three-Phase, with High-Voltage 34 500 Volts and below, Low-Voltage 216Y/125 and 480Y/277 Volts — Requirements IEEE C57.12.58-1991 (R1996) Guide for Conducting a Transient Voltage Analysis of a Dry-Type Transformer Coil IEEE C57.12.59-2000 Guide for Dry-Type Transformer Through-Fault Current Duration Draft C57.12.60-1998 Guide for Test Procedures for Thermal Evaluation of Insulation Systems for Solid- Cast and Resin-Encapsulated Power and Distribution Transformers ANSI C57.12.70-1978 (R1992) American National Standard Terminal Markings and Connections for Distribution and Power Transformers IEEE C57.12.80-1978 (R1992) Standard Terminology for Power and Distribution Transformers IEEE C57.12.91-1995 Standard Test Code for Dry-Type Distribution and Power Transformers IEEE C57.13-1993 Standard Requirements for Instrument Transformers IEEE C57.13.1-1981 (R1992) Guide for Field Testing of Relaying Current Transformers IEEE C57.13.3-1983 (R1991) Guide for the Grounding of Instrument Transformer Secondary Circuits and Cases IEEE C57.15-1986 (R1992) Standard Requirements, Terminology, and Test Code for Step-Voltage and Induction- Voltage Regulators IEEE C57.16-1996 Standard Requirements, Terminology, and Test Code for Dry-Type Air-Core Series- Connected Reactors IEEE C57.18.10-1998 Standard Practices and Requirements for Semiconductor Power Rectifier Transformers IEEE C57.19.00-1991 (R1997) Standard General Requirements and Test Procedures for Outdoor Power Apparatus Bushings IEEE C57.19.01-1991 (R1997) Standard Performance Characteristics and Dimensions for Outdoor Apparatus Bushings IEEE C57.19.03-1996 Standard Requirements, Terminology, and Test Code for Bushings for dc Applications IEEE C57.19.100-1995 (R1997) Guide for Application of Power Apparatus Bushings IEEE C57.21-1990 (R1995) Standard Requirements, Terminology, and Test Code for Shunt Reactors Rated over 500 kVA *IEEE C57.94-1982 (R1987) Recommended Practice for the Installation, Application, Operation, and Maintenance of Dry-Type General Purpose Distribution and Power Transformers IEEE C57.96-1989 Guide for Loading Dry-Type Distribution and Power Transformers IEEE C57.98-1993 Guide for Transformer Impulse Tests (an errata sheet is available in PDF format) IEEE C57.105-1978 (R1999) Guide for Application of Transformer Connections in Three-Phase Distribution Systems — continued © 2004 by CRC Press LLC © 2004 by CRC Press LLC
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ELECTRIC POWER TRANSFORMER ENGINEER
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I wish to recognize the interest of
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Contents 1 Theory and Principles Ch
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1.3 Equivalent Circuit of an Iron-C
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designer starts to make a design fo
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• Transient voltages generated du
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the transformer’s bushings and, m
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% regulation = [(V NL - V FL )/V FL
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In core-form transformers, the wind
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FIGURE 2.1.14 Layer windings (singl
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the transformer design, which may b
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consumer’s service circuit is a d
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FIGURE 2.2.3 Single-phase transform
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is installed so that the tank never
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above which persons might be burned
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FIGURE 2.2.16 Two-bushing subway. (
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carbon steel or the very expensive
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FIGURE 2.2.31 Radial-style dead fro
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FIGURE 2.2.36 Complete transformer
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voltage in each winding simultaneou
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mounted transformers can have arres
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V S + V S I V L Z=R+jX a) V L V S V
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Z = jX (2.3.19) 0.7 Then the curren
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X1 L* X1 S =X1 L X2 L* X3 L* a) S L
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150 V(%) 100 50 0 -50 40 80 T(s) 12
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2.3.8.1.2 Series Connection • The
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A six-pulse single-way transformer
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The degree of coupling also influen
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where I h = current for the hth har
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In the case of liquid-filled transf
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FIGURE 2.4.21 A 36-pulse system mad
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Vacuum-pressure encaps ulated — T
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FIGURE 2.6.1 Typical wiring and sin
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a) H1 b) Ip X2 FLUX H2 LEAKAGE FLUX
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and for CTs is TCF = RCF - (PA/2600
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RCF x Bx Bt RCF t - RCF 0 co
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2000 1000 5% Vex BANDWITH FROM NOMI
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This may be more useful when operat
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also some uncertainty in repeatabil
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FIGURE 2.6.25 Standard two-element
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2.7 Step-Voltage Regulators Craig A
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Source Bypass Switch Source Bypass
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2.7.4 Theory A step-voltage regulat
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FIGURE 2.7.22 Equalizer winding inc
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TABLE 2.7.4 Increase in Ampere Load
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References IEEE, Standard Requireme
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300% FIGURE 2.8.4 Schematic of a co
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TABLE 2.8.1 Typical Sizing Workshee
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Input with Interruption Ferro Outpu
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FIGURE 2.8.20A Performance of a rid
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• Input frequency or frequency ra
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References 1. Sola/Hevi-Duty Corp.,
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FIGURE 2.9.5 Typical phase-reactor
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FIGURE 2.9.10 Two generator arrange
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• Overloading of lines • Increa
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FIGURE 2.9.23 34-kV, 25-MVAR (per p
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V 90 ( X X ) s T (2.9.10a) where,
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Therefore, Line reactive losses = (
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ate of rise of transient-recovery v
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the LLCR is provided in IEEE Std. C
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aluminum shielding, i.e., an oil-im
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Leo J. Savio ADAPT Corporation Ted
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3.1.2.2.2 Heat Dissipation A second
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FIGURE 3.2.1 Solid-type bushing. ma
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1.6 cm. This means that most of the
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where HS = steady-state bushing ho
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the conductivity of the water-solub
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of 178 ohm-m, and a test duration o
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2. Easley, J.K. and Stockum, F.R.,
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FIGURE 3.3.5 Reactance-type LTC, in
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FIGURE 3.3.10 LTC with delta connec
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3.3.5 Selection of Load Tap Changer
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FIGURE 3.3.19 Effect of the leakage
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References Goosen, P.V. , Transform
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If i 1 is the full-load current rat
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TABLE 3.4.1 Loading Recommendations
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3.5.4 Three-Phase Transformer Conne
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FIGURE 3.5.4 Interconnected star-gr
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3.6.1.1 Standards ANSI standards fo
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ANSI standards. LTC control setting
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FIGURE 3.6.7 Discharging the capaci
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FIGURE 3.6.10 Standard switching-im
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voltage of the excited winding, rea
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FIGURE 3.6.18 Current, voltage, and
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TABLE 3.6.3 Transformer Short-Circu
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FIGURE 3.7.3 Control for voltage re
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FIGURE 3.7.6A Feeder with power-fac
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3. Circulating current (current bal
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FIGURE 3.7.10 Control block diagram
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Primary Current (Amps) 60 40 20 0 -
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current transformer having two prim
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87R1 87BL1 (A) Independent Harmonic
Page 185 and 186: Winding 1 Secondary Currents Data A
Page 187 and 188: Y Y 20 18 3 rd Harmonic CTR1=40 CTR
Page 189 and 190: 230 kV 3 180 MVA 138 kV 5 CTR1 = 2
Page 191 and 192: 29. Concordia, C. and Rothe, F.S.,
Page 193 and 194: FIGURE 3.9.1 Measurement of pressur
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Page 197 and 198: Gade, S., Sound Intensity Instrumen
Page 199 and 200: nected. This steady-state voltage d
Page 201 and 202: where [A] = state matrix [B] = inpu
Page 203 and 204: where C = capacitance between the t
Page 205 and 206: L ijo = N i N j ijo (3.10.31) 1.4
Page 207 and 208: % VOLTAGE % VOLTAGE 100 BIL 90 50 3
Page 209 and 210: 29. Degeneff, R.C., Reducing Storag
Page 211 and 212: All connections should be cleaned a
Page 213 and 214: 6. Costs to set up and use a mobile
Page 215 and 216: Records of relay operation must be
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Page 221 and 222: The next data-processing step is to
Page 223 and 224: temperature. As the transformer coo
Page 225 and 226: 3.13.3.2 Instrument Transformers Th
Page 227 and 228: FIGURE 3.13.5 Analysis of bushing s
Page 229 and 230: temperature. Under abnormal conditi
Page 231 and 232: 3.14.1.2 Accredited Standards Commi
Page 233 and 234: FIGURE 3.14.4 IEC technical-committ
Page 235: TABLE 3.14.2 Relevant Documents for
Page 239 and 240: TABLE 3.14.9 Relevant Documents for
Page 241: TABLE 3.14.13 Relevant Documents fo
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