标题: K.25：光缆的防护-(199605) [打印本页] 作者: 刘跃龙 时间: 2008-7-13 04:43 标题: K.25：光缆的防护-(199605) K.25：光缆的防护-(199605)
---The metallic elements of an optical fibre cable shall be continuous, i.e. it shall be connected across all splices regenerators, etc., along the length of the cable. The metallic elements shall be connected to the equipotential bonding bar (e.p.b.b.), either directly or through a SPD, at the ends of the cable一条光缆中的金属部件沿光缆长度方向应保持连续，即所有接头及再生器处的金属部件应接通。光缆终端的金属部件应直接接至等电位连接排或通过浪涌保护器件(SPD) 接至等电位连接排。
－Interconnection of single metallic components such as armouring, moisture barrier or strength member at splices or joints can be avoided in cables which do not use metallic conductors for signals or power (see Note in 7.4).
对于没有使用金属导线来传送信号或供电的光缆，可以取消金属部件(如铠装、挡潮层或加强构件)在接头处的连接。
primary failures: Primary failures on the optical fibre cable are those which cause the interruption of service(breakage of one or more optical fibres), an unacceptable increase in attenuation of the optical fibre or an interruption in the remote power supply, if the equipment is powered by metallic conductors inside the optical cable
光缆上的一次.故障是指业务中断（一根光纤或更多光纤的断裂），光纤的衰减增加到不可容许的数值或远供电源中断（如果设备由光缆内的金属导线供电，）等故障。
secondary failures: Secondary failures on the optical fibre cable are those damages to the cable, such as the puncturing of the plastic protective covering (pinholing) and, in case, also of the metal sheath, which do not cause primary failures.二次.故障光缆的二次故障是指那些光缆损坏，比如塑料保护层上的针孔缺陷等，但不导致一次故障的故障。
frequency of primary failures (Fp): Average annual number of expected primary failures in an optical fibre installation due to direct lightning flashes.
一次故障频度(Fp)直接雷造成光纤装置预期一次故障的年均次数。
risk of primary failures (Rd): Probable average annual loss of function in the optical fibre installation due to direct lightning flashes.
一次故障风险(Rd)直接雷造成光纤装置可能的年均功能损失。
tolerable frequency of primary failures (Fa): Average annual frequency of primary failures in an optical fibre installation not requiring additional protective measures.
一次故障容许频度(Fa)无需采取附加保护措施，预期的由直接雷造成光纤装置的年均一次故障次数的最大值。
tolerable risk of primary failures (Ra): Maximum level of the risk of primary failures (Rd) due to direct lightning flashes not requiring additional protective measures.
容许的一次故障风险(Ra)
无需采取附加保护措施，由直接雷造成一次故障风险（Rd）的最大限值。
direct lightning flash: A lightning to aerial cable or to the ground surface within the equivalent arcing distance D from buried cable.
直接雷雷击架空光缆，或雷击地表面与地埋光缆的距离小于等效电弧长度D。direct lightning flash frequency (Nd): Expected average annual number of direct lightning flashes to an optical fibre installation
.直接雷频度(Nd)雷电直击光纤装置的预期年均次数。equivalent arcing distance (D): Average distance from buried cable at which a lightning can arc to the cable.
等效建弧距离(D)引起光缆建弧时，雷击点和地埋光缆之间的平均距离failure lightning current (Ia): Minimum peak value of the lightning current giving rise to a direct arc on the cable and causing primary failures.
故障电流(Ia)引起与光缆直接建弧放电并导致一次故障的雷电流的最小峰值。breakdown sheath current (Is): Current flowing in the metallic sheath which causes breakdown voltages between metallic elements inside the cable core and the metallic sheath.
屏蔽层击穿电流(Is)在光缆屏蔽层中流过，产生光缆芯内部金属加强芯与光缆金属屏蔽层间击穿电压，并导致一次故障的电流。connection current (Ic): Minimum current flowing in the interconnecting elements that causes a primary failure due to thermal or mechanical effects.
连接电流(Ic)互相连接的元件导致一次故障的最小电流值，通过热能或机械效应来估计。
impulse current (Ip): Current to be used in the test for surge current resistibility of optical fibre cables. The test generator of this current is under consideration by IEC TC 81.
脉冲电流(Ip)测试光缆对浪涌电流.耐受能力时使用的电流。这种测试电流发生器目前在研究中。
interconnecting elements: interconnecting elements: Metallic elements connecting metallic sheath(s) or the metallic strength member(s) of optical fibre cable at joints and cable ends.
互联元件在接头和光缆末端连接光缆金属屏蔽层或金属加强芯的金属元件。test current (It): Minimum current injected by arc in the cable metallic sheath that causes a primary failure due to thermal or mechanical effects.
测试电流光缆的金属屏蔽层建弧导致一次故障的最小电流，通过热能或机械效应来估计。
breakdown voltage (Ub): Impulse breakdown voltage between metallic components in the core and the metallic sheath of the optical cable.
击穿电压(Ub).光缆芯内的金属加强芯与金属屏蔽层间的脉冲击穿电压。
damage correction factor (Kd): Factor which allows a conservative evaluation of the frequency of primary failures.
损坏修正系数(Kd)允许保守估计一次故障次数的系数。surge protective device (SPD): A device that is intended to limit transient overvoltages and divert surge currents. It contains at least one non-linear component
浪涌保护器(SPD)用于限制瞬态过电压以及分流浪涌电流的装置，它包含至少一个非线型元件。equipotential bonding bar (E.B.B.): An electrically conductive bar whose electric potential is used as common reference, and to which metallic parts within the installation can be bonded.
等电位连接排(E.B.B.)用于公共电位参考的良导体排。金属装置，外部导体，电力和电信线路及其他光缆可以与之连接。direct lightning current to aerial cables (J): Minimum lightning current which strikes an aerial cable causing a flashover to ground.
架空光缆直接雷电流(J)雷击架空光缆导致对地闪络的雷电流的最小值。exposed structure: A structure, e.g. telecommunication tower, high building, which needs to be protected against direct lightning strokes
暴露建筑物诸如电信塔和高层建筑等（按IEC 61024-1-1的要求）需防直接雷的建筑物。keraunic level or thunderstorm days (Td): Number of days per year in which thunder is heard in a given location
雷暴日(Td)从年平均雷暴日数分布图获得的每年雷暴天数（见IEC 61024-1-1）ground flash density (Ng): Average number of lightning flashes to ground per square kilometre per year, concerning the region where the structure or the optical fibre cable is located.
地面落雷密度(Ng)建筑物或光缆所在区域的平均每年每平方公里雷电对地闪络次数lightning collection area: Area of ground surface which has the same annual frequency of direct lightning as the structure or the line.
引雷范围建筑物和线路有相同的每年直接雷次数的等效地表面区域。
Figure 1 represents the reference configuration for the optical fibre installations, where the connections with optical fibre cables between two Switches, between Switch and Line Termination and between Switch and line Equipment are shown
图一为光纤装置的参考结构，表示了交换机之间，交换机和线路终端之间，以及交换机和线路设备之间的光缆连接。
Construction characteristics of the cable防护措施
7.1 General
The metallic elements of an optical fibre cable shall be continuous, i.e. it shall be connected across all splices, regenerators, etc., along the length of the cable. The metallic elements shall be connected to the equipotential bonding bar (E.B.B.) either directly or through a SPD, at the ends of the cable (see Figure 3)
光缆的金属部件应该是全长范围内连续的（它们应该是跨过.全部的接头，中继器等相连接），金属线应该直接或通过一个SPD，在光缆末端连接到等电位连接排（见图3）
If the E.B.B. of the subscriber building is not available, the metallic elements of the optical fibre
cable shall be connected to a dedicated E.B.B. inside the optical network termination.
如果用户建筑没有EBB，光缆的金属部分应该连接到光网络终端内一个指定的EBB上。
For optical fibre cables with metallic elements, the following protective measures are usually considered:对于有金属芯线的光缆，下列常用防护措施可以一起考虑使用：
– use of dielectric or metal-free cables;使用电介质或无金属光缆
– choice of the cable type for both buried and aerial cables;选择有较高故障电流值的地埋和架空光缆类型
– use of the shield wires for buried cables;仅对地埋光缆使用屏蔽线
– earthing of the metal sheath along the route for aerial cables (see 5.2);仅对沿架空光缆路径的金属屏蔽层接地
– route redundancy for both buried and aerial cables;地埋和架空路径冗余
– use of surge arresters for the protection of the metallic pairs of both buried and aerial cables使用避雷器对地埋和架空电缆的金属线对进行防护。
作者: 大胡子 时间: 2008-7-14 07:55
新同学就比俺还能灌?作者: elfsabay 时间: 2008-7-21 14:51
不灌白不灌、、、。。。
