1、 IEEE Guide for Planning and Designing Transition Facilities between Overhead and Underground Transmission Lines Sponsored by the Insulated Conductors Committee IEEE 3 Park Avenue New York, NY 10016-5997 USA 8 January 2013 IEEE Power and Energy SocietyIEEE Std 1793-2012IEEE Std 1793-2012 IEEE Guide
2、for Planning and Designing Transition Facilities between Overhead and Underground Transmission Lines Sponsor Insulated Conductors Committee of the IEEE Power and Energy Society Approved 5 December 2012 IEEE-SA Standards Board Abstract: Careful consideration of the physical and electrical characteris
3、tics of overhead lines and transmission cables are necessary in designing a transition structure between the two systems. Environmental and social factors also play a role in designing a transition. By considering the factors contained in this guide, the user will be better able to design a suitable
4、 transition that balances cost, operability, environmental factors, and future flexibility. Keywords: IEEE 1793, riser poles, transition stations, transition structures The Institute of Electrical and Electronics Engineers, Inc. 3 Park Avenue, New York NY 10016-5997, USA Copyright 2013 by the Instit
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18、sk of infringement of such rights, is entirely their own responsibility. Further information may be obtained from the IEEE Standards Association. v Copyright 2013 IEEE. All rights reserved. Introduction This introduction is not part of IEEE Std 1793-2012, IEEE Guide for Planning and Designing Transi
19、tion Facilities between Overhead and Underground Transmission Lines. It is sometimes necessary to incorporate an underground cable segment into an overhead transmission line. An underground segment may be needed in areas where it is impractical to obtain overhead right-of-way, to avoid environmental
20、ly sensitive areas, to cross obstacles such as rivers or major highways, to cross airport runway safety zones, or to permit other land uses that would not be feasible with overhead lines. When an underground segment is added to an overhead transmission line, a transition facility is required. The tr
21、ansition facility provides a means to terminate the overhead transmission line, terminate the underground cable, connect the overhead and underground segments, and accommodate any ancillary systems associated with the underground cable. Underground cables have electrical and operating characteristic
22、s which are different from those of overhead lines, and which can affect the design of transition facilities. Underground transitions facilities are needed for short underground sections (“dips”), which might be measured in the hundreds to thousands of meters. Transition facilities are also required
23、 for longer underground segments, which can be several kilometers in length. The length of the underground segment can affect the transition facility design. Overhead to underground transition facilities have planning, siting, design, construction, and maintenance considerations that should be evalu
24、ated beginning in the initial stages of a transmission line project. vi Copyright 2013 IEEE. All rights reserved. Participants At the time this guide was submitted to the IEEE-SA Standards Board for approval, the IEEE Guide for Planning and Designing Transition Facilities Between Overhead and Underg
25、round Transmission Lines Working Group had the following membership: Dennis E. Johnson, Chair David M. Campilii, Vice Chair Earle C. Bascom III Jonathan E. Busby Todd S. Goyette Chris H. Grodzinski James Hunt Paul Jakob Donald E. Koonce Arthur J. Kroese Stephen F. LaCasse Michael R. Mueller Mohammed
26、 Pasha Forest L. Rong Gerald J. Ruschkofski Peter L. Tirinzoni Nijam Robert Uddin Jay A. Williams Paul Zimmerman Joseph T. Zimnoch The following members of the individual balloting committee voted on this guide. Balloters may have voted for approval, disapproval, or abstention. William Ackerman Ali
27、Al Awazi Roy Alexander Thomas Barnes Earle C. Bascom III Kenneth Bow Gustavo Brunello William Bush William Byrd Robert Christman Frank Di Guglielmo Gary Donner Dana Dufield Gary Engmann Jorge Fernandez Daher Frank Gerleve David Gilmer Edwin Goodwin Todd Goyette Randall Groves Timothy Hayden Jeffrey
28、Helzer Lee Herron Werner Hoelzl David Horvath James Hunt Dennis E. Johnson Gael Kennedy Morteza Khodaie Joseph L. Koepfinger Jim Kulchisky Stephen F. LaCasse Chung-Yiu Lam Greg Luri Arturo Maldonado Jerry Murphy Michael S. Newman Joe Nims Gary Nissen Carl Orde Lorraine Padden Donald Parker Bansi Pat
29、el Douglas Proctor Reynaldo Ramos Joseph Rezutko Michael Roberts Stephen Rodick Thomas Rozek Bartien Sayogo Dennis Schlender James Smith Jerry Smith Gary Stoedter Peter L. Tirinzoni James Tomaseski Nijam Robert Uddin John Vergis Kenneth White Jian Yu Luis Zambrano Dawn Zhao Tiebin Zhao Joseph T. Zim
30、noch vii Copyright 2013 IEEE. All rights reserved. When the IEEE-SA Standards Board approved this guide on 5 December 2012, it had the following membership: Richard H. Hulett, Chair John Kulick, Vice Chair Robert Grow, Past Chair Konstantinos Karachalios, Secretary Satish Aggarwal Masayuki Ariyoshi
31、Peter Balma William Bartley Ted Burse Clint Chaplin Wael Diab Jean-Philippe Faure Alexander Gelman Paul Houz Jim Hughes Young Kyun Kim Joseph L. Koepfinger* David J. Law Thomas Lee Hung Ling Oleg Logvinov Ted Olsen Gary Robinson Jon Walter Rosdahl Mike Seavey Yatin Trivedi Phil Winston Yu Yuan *Memb
32、er EmeritusAlso included are the following nonvoting IEEE-SA Standards Board liaisons: Richard DeBlasio, DOE Representative Michael Janezic, NIST Representative Catherine Berger IEEE Standards Program Manager, Document Development Malia Zaman IEEE Program Manager, Technical Program Development viii
33、Copyright 2013 IEEE. All rights reserved. Contents 1. Overview 1 1.1 Scope . 1 1.2 Purpose 2 2. Normative references 2 3. Planning 2 3.1 Site selection 3 3.2 System impacts 8 4. Design 15 4.1 Monopole structure layout/design 15 4.2 Transition site design 21 4.3 Other design considerations 22 4.4 Str
34、ucture installation .26 4.5 Cable installation 26 4.6 Accessories installation 27 4.7 Commissioning .28 4.8 Operational/Maintenance (O particularly for extruded dielectric and self-contained fluid-filled cables. The pipe of a pipe-type cable generally has significant fault current carrying capacity,
35、 although pipe grounding should be configured carefully to allow the fault current to reach ground. The fault current capability of a transmission cable is normally evaluated for the case of a single-line-to-ground fault, where the fault current passes through one of the cable phase conductors and m
36、ay return through the cable metallic shield or sheath. Many utilities conservatively use cable shield/sheath designs that allow for 1530 cycles in the event that primary protection fails to operate, at which point, secondary protection systems will be called upon to operate to clear the fault. Adiab
37、atic conditions are usually assumed when sizing the shield/sheath cross sectional area. A cable in a hybrid circuit may increase the fault current levels further out on the line because of the lower zero sequence impedance for cable as compared to overhead lines. Consequentially, distance relays may
38、 have to be adjusted to consider a section of cable inserted into an overhead circuit. The transition structures will typically require provisions for attaching link boxes, polarization cells or isolator surge protectors (ISP) (for cathodically protected cable systems), cable shield and arrester bon
39、ding leads, and other bonding and grounding facilities. In addition, adequate shield connections to ground at the transition facility, and adequate buried grounding conductors to establish low ground resistance and low step/touch potential issues, should be evaluated. 3.2.3.4 Overvoltage and insulat
40、ion coordination As with any transmission system, the effects of overvoltage on the transmission system need to be addressed. Overvoltage on any transmission system can be caused by lightning, switching, and system instability. Insulation coordination studies should be performed to determine the cor
41、rect insulation and protection level for hybrid overhead and underground transmission lines. The most effective way of limiting overvoltages on the underground line is to install properly sized arresters at each end of the cable. Transition facilities should have accommodations for surge arresters c
42、lose to each cable termination. This can be accomplished with the installation of suitable brackets on monopole transitions, or be incorporated in the termination support structure in transition stations. 3.2.4 Effect on protection and control An underground segment in an overhead transmission line
43、can cause a number of difficulties that should be addressed when designing a hybrid transmission line relay protection and control system. Depending on system requirements, the transition station could be as simple as a monopole structure used to connect the IEEE Std 1793-2012 IEEE Guide for Plannin
44、g and Designing Transition Facilities Between Overhead and Underground Transmission Lines 11 Copyright 2013 IEEE. All rights reserved. overhead line to the underground cable or as complicated as a substation with circuit breakers, shunt reactors, protective relaying, AC and DC power supplies and com
45、munication facilities. Each transition station design provides its own relaying concerns. Some of the main points to consider concerning protection and control of hybrid transmission lines include the following: Variations in the overall line impedance caused by having one or more parallel cables ou
46、t of service for maintenance while the remaining cable(s) and overhead portions remain in service. Impedance mismatch between the overhead and underground sections. Shunt reactors, if located at a transition station, should have protection installed locally, requiring all normal system redundancy (e
47、.g., dual AC and DC systems). Fault detection and/or location equipment at the transition station may be needed to determine if the fault is in the cable section to enable or prohibit automatic reclosing. System studies may determine that it is desirable to remove one of the parallel cables from ser
48、vice during light load periods to reduce the line charging. Switching devices (circuit breakers or circuit switchers) would be required for this capability. If there is automatic reclosing installed on the line, consideration should be given to discharging the trapped charge on the line prior to re-
49、energization. If a protective scheme requires use of potential transformers (PTs) mounted at the terminals of the underground cables, these PTs should have their secondaries connected to a load per the transformers manufacturers recommendations to prevent ferro-resonance from occuring between the underground cable capacitance and the PT inductance. This ferro-resonance can cause a very high voltage which can cause the PTs iron core to saturate. The excessive excitation current generated can cause the primary winding of the PT to fail due to thermal heatin
