[James_H._Harlow]_Electric_Power_Transformer_Engin(BookSee.org)

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The developer of a standard is presented with a range of options in pursuing the document’s acceptance as an American national standard. All methods require prior, or standing, approval until organization scope is changed from ANSI. The canvass method provides the greatest flexibility for the developer but places a greater involvement in assembling the necessary balloting group and, therefore, latitude in determining voting participants. For a developer outside an organization, the canvass list and the ASC methods provide the greatest and quickest access. The ASO route is not a normal venue for outsiders, or nonmembers, without special arrangements or agreements from the sponsoring ASO, particularly, if the document falls outside the scope of the organization’s accreditation. FIGURE 3.14.2 ANSI accredited-standards-committee approval process for C57. 3.14.2 The International Electrotechnical Commission (IEC) The International Electrotechnical Commission (IEC) is composed of a central office and approximately 100 technical committees and subcommittees. The IEC central office is located in Geneva, Switzerland. All balloting of technical documents is conducted through the central office. The national committees of each country are responsible for establishing participation status on the various technical committees and subcommittees as well as casting votes on the respective ballots. Participation status by a national committee of a country can be in one of three categories: • P-member: participates actively in the work, with an obligation to vote on all questions formally submitted for voting within the technical committee or subcommittee, to vote on enquiry drafts and final draft international standards, and whenever possible, to participate in meetings. • O-member: follows the work as an observer and, therefore, receives committee documents and has the right to submit comments and to attend meetings. • Nonmember: has neither the rights nor obligations described above for the work of a particular committee. Nevertheless, all national bodies — irrespective of their status within a technical committee or subcommittee — have the right to vote on enquiry drafts and on final-draft international standards. All ballots are cast by the national committees of the respective countries, with one vote per country. The U.S. national committee is a committee of the American National Standards Institute (ANSI), with headquarters in New York City. U.S. technical interface with IEC TCS/SCS is via a technical advisory group (TAG) and a technical advisor (TA). TAGs are administered by an organizational TAG administrator. TAs are appointed by the U.S. National Committee Executive Committee (EXCO) to represent U.S. interests on the various technical committees and subcommittees. TA appointments are based on technical experience and capability. TAs are responsible for establishing TAGs to develop consensus positions of technical issues and to assist the TA in technical representation. This includes the nomination of working-group experts. As stated above, all balloting of technical documents is conducted through the central office of the IEC. The ballots are first distributed to the national committees. The national committees next send the ballots to the appropriate technical experts for input. Within the U.S., ballots are submitted to the TA/ TAG. The TA/TAG administrator has the responsibility to distribute the ballot to the TAG for direction and/or comment. A consensus process is used to be certain that votes are truly representative of the U.S. position. The TA/TAG administrator sends all recommended actions to the secretary of the USNC. The secretary then sends the official U.S. vote to the IEC central office. Figure 3.14.4 shows a flow diagram of the IEC ballot process. 3.14.3 Relevant Power Transformer Standards Documents There are numerous issued documents that apply to the specifications and performance requirements for the various power transformers in the industry today. This section organizes them in ascending order of power ratings, in the following categories: © 2004 by CRC Press LLC © 2004 by CRC Press LLC
FIGURE 3.14.4 IEC technical-committee document approval process. FIGURE 3.14.3 ANSI accredited-standards-organization approval process. 1. Small dry-type transformers NEMA UL IEC 2. Electronics power transformers IEEE 3. Low-voltage medium-power dry-type transformers NEMA UL IEC 4. Medium-voltage and large-power dry-type transformers IEEE NEMA UL IEC 5. Liquid-filled transformers IEEE NEMA IEC 3.14.3.1 Small Dry-Type Transformers 3.14.3.1.1 NEMA ST-1, Specialty Transformers (except General-Purpose Type) This standards publication covers control transformers, industrial control transformers, Class 2 transformers, signaling transformers, ignition transformers, and luminous-tube transformers. The publication © 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 -
Page 181 and 182: current transformer having two prim
Page 183 and 184: 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
Page 195 and 196: H 2m 1. Vertical Forced Air 2. Prin
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
Page 217 and 218: • Has heating occurred as the res
Page 219 and 220: a reference value) of the currents
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: 3.14.1.2 Accredited Standards Commi
Page 235 and 236: TABLE 3.14.2 Relevant Documents for
Page 241: TABLE 3.14.13 Relevant Documents fo
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