ICEA P-117-734-2016 Ampacities For Single-Conductor Solid Dielectric Power Cable 15 kV Through 35 kV.pdf

1、 Ampacities For Single-Conductor Solid Dielectric Power Cable 15 kV Through 35 kV ANSI/ICEA P-117-734-2016 2016 by INSULATED CABLE ENGINEERS ASSOCIATION, Inc. ANSI/ICEA P-117-734-2016 Approved as an American National Standard ANSI Approval Date: February 23, 2016 Insulated Cable Engineers Assoc., In

2、c. Publication No. ICEA P-117-734-2016 Ampacities For Single-Conductor Solid Dielectric Power Cable 15 kV Through 35 kV 2016 Approved July 2015 by Insulated Cable Engineers Association, Inc. Approved February 23, 2016 by American National Standards Institute, Inc. Published by: Insulated Cable Engin

3、eers Association, Inc. Copyright 2015 by the Insulated Cable Engineers Association, Incorporated (ICEA). All rights including translation into other languages, reserved under the Universal Copyright Convention, the Berne Convention for the Protection of Literary and Artistic Works, and the Internat

4、ional and Pan American Copyright Conventions. 2016 by the Insulated Cable Engineers Association NOTICE AND DISCLAIMER The information in this publication was considered technically sound by the consensus of persons engaged in the development and approval of the document at the time it was developed.

5、 Consensus does not necessarily mean that there is unanimous agreement among every person participating in the development of this document. The Insulated Cable Engineers Association, Inc. (ICEA) standards and guideline publications, of which the document contained herein is one, are developed throu

6、gh a voluntary consensus standards development process. This process brings together persons who have an interest in the topic covered by this publication. While ICEA administers the process and establishes rules to promote fairness in the development of consensus, it does not independently test, ev

7、aluate, or verify the accuracy or completeness of any information or the soundness of any judgements contained in its standards and guideline publications. ICEA disclaims liability for personal injury, property, or other damages of any nature whatsoever, whether special, indirect consequential, or c

8、ompensatory, directly or indirectly resulting from the publication, use of, application, or reliance on this document. ICEA disclaims and makes no guaranty or warranty, expressed or implied, as to the accuracy or completeness of any information published herein, and disclaims and makes no warranty t

9、hat the information in this document will fulfill any of your particular purposes or needs. ICEA does not undertake to guarantee the performance of any individual manufacturer or sellers products or services by virtue of this standard or guide. In publishing and making this document available, ICEA

10、are not undertaking to render professional or other services for or on behalf of any person or entity, nor is ICEA undertaking to perform any duty owed by any person or entity to someone else. Anyone using this document should rely on his or her own independent judgement or, as appropriate, seek the

11、 advice of a competent professional in determining the exercise of reasonable care in any given circumstances. Information and other standards on the topic covered by this publication may be available from other sources, which the user may wish to consult for additional views or information not cove

12、red by this publication. ICEA has no power, nor does it undertake to police or enforce compliance with the contents of this document. ICEA does not certify, test, or inspect products, designs, or installations for safety or health purposes. Any certification or other statement of compliance with any

13、 health or safety-related information in this document shall not be attributable to ICEA and is solely the responsibility of the certifier or maker of the statement. ICEA P-117-734 -2016 Page i 2016 by the Insulated Cable Engineers Association CONTENTS FOREWORD . iii PREFACE iv SECTION 11 GENERAL.1

14、1.1 Introduction 1 1.2 Scope 1 SECTION 2 . 2 EFFECT OF SHIELD CURRENTS ON CABLE AMPACITY 2 SECTION 3 . 3 TECHNICAL FEATURES OF TABLES 3 3.1 Parameters 3 3.1.1 Voltages 3 3.1.2 Load and loss factors 3 3.1.3 Dielectric loss 3 3.1.4 Thermal resistivity 4 3.1.5 Temperatures. 4 3.1.6 Conductors 4 3.1.7 E

15、xtruded conductor shield (stress control layer) 5 3.1.8 Insulation. 5 3.1.9 Extruded Insulation shield 5 3.1.10 Metallic shield . 5 3.1.11 Jackets . 6 3.1.12 Types of installations 6 3.2 Use of ampacity tables . 6 3.2.1 General 6 3.2.2 Metallic shield . 6 3.2.3 Calculation of DC shield resistance 6

16、3.2.4 Temperature limitations 7 3.3 Earth interface temperature 8 3.4 Adjustments for changes in parameters . 8 3.4.1 Adjustment for change in ambient earth temperature . 8 3.4.2 Adjustment for change in conductor temperature . 10 3.4.3 Adjustment for change in maximum earth interface temperature 10

17、 SECTION 4 . 12 INFLUENCING FACTORS ON CABLE AMPACITY.14 4.1 Shield loss 12 4.1.1 Shield circulating current loss . 12 4.1.2 Effects of phasing . 13 4.1.3 Shield eddy current loss 13 4.2 Earth thermal resistivity . 14 4.3 Earth interface temperature 19 4.4 Installation types 16 4.5 Other important f

18、actors 17 4.5.1 Nearby heat sources.17 ICEA P-117-734-2016 Page ii 2016 by the Insulated Cable Engineers Association 4.5.2 Magnetic conduit.17 4.5.3 SIC and dissipation factor17 4.5.4 Burial Depth.17 4.5.5 Duct size.18 4.5.6 Impact of risers.19 4.6 General equation for ampacity . 19 SECTION 5 . 20 R

19、EFERENCES . 20 SECTION 6 . 21 Installation configurations 21 SECTION 7 . 23 TABLE OF AMPACITIES. 23 INDEX OF PAGE NUMBERS FOR AMPACITY TABLES23 TABLES AND CHARTS TABLE 1 Voltage range 5 TABLE 2 Metallic shield types . 5 TABLE 3 Helically applied lay factor . 7 TABLE 4 Electrical resistivity. 7 TABLE

20、 5 Ambient earth correction factors . 9 TABLE 6 Ambient air correction factors 9 TABLE 7 Effect of cable phasing on ampacity of double circuits 13 CHART 1 Earth thermal resistivity vs ampacity . 14 CHARTS 2-8 Relationship of soil resistivity to ampacity and effect on earth interface temp. 15 CHART 9

21、 Direct buried vs duct 16 CHART 10 Number of circuits in duct bank vs ampacity . 17 CHART 11 Effect of burial depth on ampacity . 18 CHART 12 Ampacity vs duct size. 18 CHART 13 Riser vs duct vs direct buried . 19 ICEA P-117-734 -2016 Page iii 2016 by the Insulated Cable Engineers Association Forewor

22、d ICEA Standards are adopted in the public interest and are designed to eliminate misunderstandings between the manufacturer and the user and to assist the user in selecting and obtaining the proper product for his particular need. Existence of an ICEA standard does not in any respect preclude the m

23、anufacture or use of products not conforming to the standard. Requests for interpretation of this Standard must be submitted in writing to: Insulated Cable Engineers Association, Inc. An official written interpretation will be provided. The Association will welcome any suggestions on ways to improv

24、e this Standard. ICEA P-117-734-2016 Page iv 2016 by the Insulated Cable Engineers Association Preface The first industry ampacity tables were published in December 1943 by the Insulated Power Cable Engineers Association (IPCEA) under the title Current Carrying Capacity of Impregnated Paper, Rubber

25、and Varnished Cambric Insulated Cables. These tables were based on the best available information at the time they were published and served the industry well for many years. As a result of interest in this subject by the AIEE Insulated Conductors Committee and recognition of the fact that new techn

26、iques had been developed for making ampacity calculations through greater understanding of the thermal circuit, a joint AIEE-IPCEA Working Group was formed to prepare a new ampacity publication. In 1962 a completely new edition was published in two volumes for copper and aluminum conductor entitled

27、Power Cable Ampacities, AIEE Pub. No. S-135, IPCEA Pub. No. P-46-426 1. (IPCEA was changed to ICEA in 1979, dropping the “P” for power when communications manufacturers joined the association) This publication covered several cable types including, for the first time, oil-filled and gas-filled impre

28、gnated paper insulated cables in a variety of installations. The ampacities in these tables are still considered appropriate for the designated installation conditions and parameters. The 1962 tables do not adequately cover ampacities for single-conductor solid-dielectric cables with shields designe

29、d for stringent fault current conditions and directly buried concentric-neutral three-phase cables. The increasing use of these constructions prompted the Cable Characteristics Subcommittee of the IEEE Power Engineering Society to consider a supplement to these tables. A Task Group was formed to stu

30、dy the problems and to prepare this publication. In particular the Group considered the effect on ampacities of (1) shield losses in single-conductor cables and (2) temperatures in the earth surrounding buried cables and ducts. Subsequently, Tables 1 through 80 were approved on March 22, 1972 by IPC

31、EA and NEMA as Authorized Engineering Information. On May 17, 1976, IPCEA and NEMA approved the expansion of this publication to include 69 kV cables. This resulted in the revision of paragraphs A through E and Tables A and B and in the addition of Tables 81 through 128. On September 26, 1988, NEMA

32、reaffirmed the ICEA P-53-426/NEMA WC50 standard In 2008 the Utility Power Cable Standards Technical Advisory Committee (UPCSTAC) Task Group was formed to address the need for tables to cover ampacities for single-conductor cables with an extruded LLDPE jacket which had become the standard cable desi

33、gn for Utility distribution cables 15 kV through 35 kV. These tables are intended to compliment the IEEE 835 Standard Power Cable Ampacity Tables-1994. The following companies or persons have contributed to the computation of the ampacity tables for the new ICEA P-117-734 publication: General Cable

34、Southwire Nexans Ritchie Harp - Oncor Mike Smalley We Energies Greg Stano - WPS Jeff Helzer OG only the most common conductor sizes were used. ICEA P-117-734-2016 Page 5 2016 by the Insulated Cable Engineers Association 3.1.7 Extruded Conductor Shield (Stress Control Layer) Extruded conductor shield

35、 thickness is per ANSI/ICEA S-94-649 and S-97-682. 3.1.8 Insulation Cross-linked polyethylene or ethylene propylene rubber in the following thickness: Voltage Range Table 1 kV Rating Conductor Size, AWG/kcmil Nominal Insulation Thickness, mils 15 35 #2 -1000 1/0 - 1000 175 345 3.1.9 Extruded Insulat

36、ion Shield Extruded semi-conducting insulation shield thickness per ANSI/ICEA S-94-649 and S-97-682. 3.1.10 Metallic Shield Metallic Shield Types Table 2 Conductor Size (AWG/kcmil) 15 kV 35 kV Neutral Size Neutral Size Al Conductor Cu Conductor Al Conductor Cu Conductor #2 and #1 Full Full - - 1/3 1

37、/3 - - 10 mil LACT 10 mil LACT - - 1/0 -4/0 Full Full Full Full 1/3 1/3 1/3 1/3 10 mil LACT 10 mil LACT 10 mil LACT 10 mil LACT 350 Full - Full - 1/3 1/3 1/3 1/3 1/6 1/6 1/6 1/6 10 mil LACT 10 mil LACT 10 mil LACT 10 mil LACT 500 - 750 1/3 1/3 1/3 1/3 1/6 1/6 1/6 1/6 1/12 1/12 1/12 1/12 10 mil LACT

38、10 mil LACT 10 mil LACT 10 mil LACT 1000 1/3 1/3 1/3 - 1/6 1/6 1/6 1/6 1/12 1/12 1/12 1/12 10 mil LACT 10 mil LACT 10 mil LACT 10 mil LACT ICEA P-117-734-2016 Page 6 2016 by the Insulated Cable Engineers Association Note: LACT denotes Longitudinally Applied Corrugated Tape. Full, 1/3, 1/6, and 1/12

39、denotes the conductance of the cable shield wires compared to the conductance of the cable phase conductor. 3.1.11 Jackets Extruded LLDPE jacket thickness shall be per ANSI/ICEA S-94-649 and S-97-682. 3.1.12 Types of Installation Direct Earth Burial 1. Single, trefoil and spaced configurations Figur

40、es 1 through 6. 2. Burial depth 36 inches. Buried Duct 1. Single, Trefoil and spaced configurations Figures 7 through 12. 2. Duct size based on minimum of 0.5” clearance for three phase circuits and AEIC CG5 Section 6.4.1 for single-phase circuits. 3. PVC (Schedule 40) ducts were assumed to be direc

41、tly buried without encasement in concrete. 4. Burial depth 36 inches to the center of the duct. 3.2 USE OF AMPACITY TABLES 3.2.1 General The index on Page 23 shows the page number of the ampacity table for specific cables dependent on conductor metal (copper or aluminum), voltage rating (15 kV or 35

42、 kV), earth resistivity (90 RHO and 120 RHO), single or three-phase operation, single or double circuit arrangement, duct or direct earth burial, and single conductors in spaced or trefoil configuration. Ampacities for trefoil configurations are considered to apply to the installation of three singl

43、e-conductor cables in a common duct and to three single-conductor cables buried in the earth essentially in contact with each other. Linear interpolation for intermediate voltage ratings may be made with minimal error. 3.2.2 Metallic Shield Ampacities for full, 1/3, 1/6, and 1/12 soft bare copper co

44、ncentric neutrals and also 10 mil longitudinally applied corrugated copper tape (LACT) are given. 3.2.3 Calculation of DC Shield Resistance The DC resistances at 25C of various metallic shield designs may be calculated as follows: Concentric Wire Shield 2ndLRfss= (E4) Longitudinally Applied Corrugat

45、ed Tape Shield ( ) tBDARisfss05. 273.1 +=(E5) Where ICEA P-117-734-2016 Page 7 2016 by the Insulated Cable Engineers Association Rs= DC resistance in micro ohms per foot at 25C. Af= Increase in tape shield length due to corrugations. A typical value for various tape shield thicknesses is 1.20. B = T

46、ape overlap. A typical value is 0.375 inches. d = Neutral wire diameter in inches. Dis= Diameter over the insulation shield in inches. Lf= Lay factor is the increase in length of wires/flat straps due to helical application . The approximate lay factor for various lengths of lay of helically applied

47、 wires/flat straps is as follows: Helically Applied Lay Factor Table 3 X Lf(Lay Factor) 6 8 10 1.13 1.07 1.05 X represents the ratio of length of lay to the diameter over the wire or flat strap shield. n = Number of wires/flat straps. s= Electrical resistivity, cmil/ft. The electrical resistivity of

48、 copper or aluminum is as follows: Electrical Resistivity Table 4 Material s at 25C Uncoated annealed copper (100% IACS) Aluminum (61% IACS) 10.575 17.345 t = Thickness, inches. 3.2.4 Temperature Limitations Ampacities are given for each of the following: 1. Maximum conductor temperature of 90C (15 and 35 kV). 2. Maximum conductor temperature of 105C (15 and 35 kV). Earth interface temperature is indicated for each ampacity calculation. Attention should be given to the interface temperature when considering the conductor size and ampacity which may