1、 I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n ITU-T K.109 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (11/2015) SERIES K: PROTECTION AGAINST INTERFERENCE Installation of telecommunication equipment on utility poles Recommendation ITU-T K.109 Rec. ITU-T K.109 (11/2015) i
2、Recommendation ITU-T K.109 Installation of telecommunication equipment on utility poles Summary Recommendation ITU-T K.109 provides guidelines for the installation of telecommunication equipment and/or antennas on utility poles. These guidelines cover the clearances from the power conductors, the re
3、quirements for insulation, earthing and bonding, and the protective procedures to avoid interference and damage from the electromagnetic fields generated by the nearby power conductors and lightning flashes. The power distribution lines considered are those operating in alternating or direct current
4、, with nominal voltages up to 25 kV. These lines may be used for power distribution, street lighting, or electrified railways. History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T K.109 2015-11-29 5 11.1002/1000/12670 Keywords Clearances, earthing, joint use of poles, power lines
5、, telecommunication equipment, utility poles. * To access the Recommendation, type the URL http:/handle.itu.int/ in the address field of your web browser, followed by the Recommendations unique ID. For example, http:/handle.itu.int/11.1002/1000/11830-en. ii Rec. ITU-T K.109 (11/2015) FOREWORD The In
6、ternational Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical,
7、 operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in tu
8、rn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOT
9、E In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure,
10、e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words “shall“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of such words does not
11、 suggest that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTSITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the
12、evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, whi
13、ch may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2016 All rights reserved. No part of this publication m
14、ay be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T K.109 (11/2015) iii Table of Contents Page 1 Scope . 1 2 References . 1 3 Definitions 1 3.1 Terms defined elsewhere 1 3.2 Terms defined in this Recommendation . 2 4 Abbreviations and acronyms 2 5 Conve
15、ntions 2 6 General considerations 2 7 Resistibility requirements . 2 8 Minimum clearances . 2 9 Installation of the equipment 3 10 Earthing and bonding 4 11 Protection against electromagnetic fields . 5 Bibliography. 7 Rec. ITU-T K.109 (11/2015) 1 Recommendation ITU-T K.109 Installation of telecommu
16、nication equipment on utility poles 1 Scope This Recommendation provides guidelines for the installation of telecommunication equipment and/or antennas on utility poles carrying power distribution lines. The power lines considered are those operating in alternating or direct current, with nominal vo
17、ltages up to 25 kV. These lines may be used for power distribution, street lighting, or traction lines (electrified railways). For the procedures regarding the joint use of poles between telecommunication lines and power lines, especially the prevention of accidental contacts between these lines (po
18、wer-cross), the user shall refer to b-ITU-T K.108. For guidance on the installation of telecommunication equipment in towers of power transmission lines (above 25 kV), the user shall refer to b-ITU-T K.57. Some equipment used for smart-grid applications may contain telecommunication interfaces used
19、for supervision and control of the electric power grid, which may be installed close to or on the energized power conductors. This type of equipment is outside the scope of this Recommendation. 2 References The following ITU-T Recommendations and other references contain provisions which, through re
20、ference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the mo
21、st recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. ITU-T K.45 Recom
22、mendation ITU-T K.45 (2015), Resistibility of telecommunication equipment installed in the access and trunk networks to overvoltages and overcurrents. ITU-T K.50 Recommendation ITU-T K.50 (2000), Safe limits of operating voltages and currents for telecommunication systems powered over the network. I
23、EC 60060-1 IEC 60060-1 (2010), High-voltage test techniques - Part 1: General definitions and test requirements. 3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the following terms defined elsewhere: 3.1.1 low-voltage: Voltage having a value below a conventionally adopted limit. N
24、OTE For the distribution of AC electric power, the upper limit is generally accepted to be 1000 V. (IEC IEV 151-15-03 of b-IEC IEV) 3.1.2 residual current device (RCD): A mechanical switching device designed to make, carry and break currents under normal service conditions and to cause the opening o
25、f the contacts when the residual current attains a given value under specified conditions. (IEC IEV 442-05-02 of b-IEC IEV). NOTE A residual current device can be a combination of various separate elements designed to detect and evaluate the residual current and to make and break current. 2 Rec. ITU
26、-T K.109 (11/2015) 3.2 Terms defined in this Recommendation None. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: AC Alternating Current DC Direct Current EBB Equipotential Bonding Bar ESD Electrostatic Discharge PEN Protective Earth and Neutral RCD Re
27、sidual Current Device RF Radio-Frequency SPD Surge Protective Device VN Nominal phase-to-phase Voltage (of the power line) 5 Conventions None. 6 General considerations Telecommunication operators that wish to install equipment on poles already used by power utilities are recommended, when national l
28、aws and regulations permit such an arrangement, to take the following general considerations into account: the economic and aesthetic advantages to be derived from installing telecommunication equipment on utility poles; the use of utility poles by telecommunication operators increases the likelihoo
29、d of danger in comparison with that of an exclusive pole, both to staff and to the equipment. Special training of personnel working in such environments is highly desirable, especially when the nominal power line voltage is above 1 kV; special formal agreements are desirable between the telecommunic
30、ation operator and the power utility in the case of such installation, in order to define responsibilities. 7 Resistibility requirements Telecommunication equipment intended to be installed on utility poles shall comply with the resistibility requirements contained in ITU-T K.45. 8 Minimum clearance
31、s In order to reduce the likelihood of accidents due to the proximity between the telecommunication equipment and the energized power conductors, a minimum clearance shall be maintained: the minimum clearance between the telecommunication equipment (including its antenna) and the lighting fixture at
32、tached to the pole shall be 0.2 m; the minimum clearance between the telecommunication equipment (including its antenna) and a power line conductor, as a function of its nominal voltage (VN) and insulation, is given in Table 1. Rec. ITU-T K.109 (11/2015) 3 Table 1 Minimum clearances between telecomm
33、unication equipment and power conductors Nominal voltage (kV) Minimum clearance (m) AC DC Insulated conductor Bare conductor VN 1(1) VN 1.5(1) 0.5 1.0 1 VN 15 1.5 VN 23 1.0 1.5 15 VN 25 23 VN 38 1.5 2.0 (1) Low-voltage The minimum clearances for the installation of telecommunication equipment in low
34、-voltage utility poles are shown in Figure 1. The upper limit shown in this figure shall be observed during the installation of the equipment, taking into account the height of its antenna. Figure 1 Minimum clearances for telecommunication equipment in low-voltage utility poles 9 Installation of the
35、 equipment The installation of telecommunication equipment on a utility pole depends on the type of pole considered. The utility poles can be classified as conductive or non-conductive. Conductive poles are those made of any metallic material (e.g., galvanized steel) or made of concrete with an inte
36、rnal steel reinforcement. Non-conductive poles are those made of wood, glass fibre, or any other composite material. Non-conductive poles carrying a bare earthing down-conductor of the power line shall be treated as a conductive pole. If the equipment is installed on the surface of a non-conductive
37、pole, no special treatment is required. In this case, the equipment can be attached directly to the pole using regular fittings. If the telecommunication equipment is installed on the surface of a conductive pole, it may require additional protective procedures. This issue is currently under study.
38、4 Rec. ITU-T K.109 (11/2015) 10 Earthing and bonding The earthing procedure applied to the telecommunication equipment may depend on the characteristics of the equipment enclosure. Any earthing procedure shall be agreed upon with the power utility and follow the applicable national rules. If the equ
39、ipment enclosure is plastic or made of other non-conducting material, the equipment does not need to be connected to an earthing system. In this case, the service personnel shall be aware of the existence of any accessible live parts inside of the equipment. If the equipment enclosure is metallic, t
40、he following possibilities shall be considered: if the telecommunication operator and the power utility agree, the equipment enclosure shall be bonded to the utilitys protective earth conductor (if available). This situation is illustrated in Figure 2, where the protective earth and neutral (PEN) co
41、nductor is bonded to the equipment metallic enclosure through an equipotential bonding bar (EBB); if the protective earth conductor is not available, the equipment shall be earthed by a dedicated down-conductor and an earthing electrode. In this case, the protection of the equipment against an inter
42、nal short-circuit to the enclosure shall be provided by a residual current device (RCD), as shown in Figure 3; if the equipment is remotely powered through the telecommunication line according to ITU-T K.50 or if it is self-powered by means of a low-voltage source (e.g., photovoltaic cell), then it
43、does not need to be earthed. Figure 2 Equipment earthing by the PEN conductor Rec. ITU-T K.109 (11/2015) 5 Figure 3 Equipment earthing by a dedicated conductor 11 Protection against electromagnetic fields When telecommunication equipment is installed on a utility pole, it is exposed to the electroma
44、gnetic fields generated by the power conductors. Damage to the equipment can be caused by the electric field generated by a power conductor, which can be installed on the same pole or on a nearby line. Field experience shows that the power-frequency electric fields from a nearby power conductor can
45、damage the input radio-frequency (RF) circuit of certain types of radio transceivers. This is usually the case of radio transceivers whose RF circuit is coupled to the antenna through a series capacitor. For the low-frequency inducing field, the stray capacitance between the power conductor and the
46、antenna forms a capacitive voltage divider, resulting in a substantial voltage applied to the input capacitor. Depending on the capacitor characteristics, the voltage of the power conductor and the relative position between the antenna and the power conductor, the input capacitor may be damaged and
47、put the transceiver out of service. Even if there is no power line nearby, this type of transceiver can be damaged due to lightning flashes. The coupling process is similar to the one described before, but in this case the inducing electric field is generated by the lightning flash. Details about th
48、is mechanism and some protective measures can be found in b-Barbosa. In order to avoid this kind of damage, it is recommended that the radio transceiver used in utility poles has a shunt inductor between the RF circuit and the antenna. This inductor presents a short-circuit to the power-frequency an
49、d lightning electromagnetic fields, while presenting an open-circuit to the RF signal. There are several commercial transceivers that use this type of filter and this is a key aspect for providing reliable operation when attached to a utility pole. The shunt inductor also provides protection against electrostatic discharges (ESDs) and this is often the main reason for its installation. The RF circuits protected by shunt inductors are often referred as “DC earthed“ or “DC grounded“. Figure 4 shows a diagram wit
