ITU-TK光缆的防护.docVIP

Citccsj-3 PAGE  PAGE 27 ITU-T Recommendation K.25 Protection of optical fibre cables 光缆的防护-(1996/2000) 1 Scope and object 第一章 范围和目标 The scope of this Recommendation is the protection against lightning of telecommunication lines in fibre optics installations. The object of this Recommendation is to limit the number of possible primary failures occurring in the optical fibre cable in a specified installation within values which are lower than or equal to the limit value, defined as the tolerable frequency of primary failures. Consequently, this Recommendation points out a method for both calculating the possible number of primary failures and choosing the feasible protective measures. Secondary failures are not considered in this Recommendation. 本标准涉及范围是基于光纤装置的电信线路防雷保护光缆设计。 本标准的目标是为了限制某一特定光纤装置中的光缆可能产生重大故障的次数，使其小于或等于规定的重大故障的次数，该值定义为一次故障容许频度。 因此，本标准提出了计算一次故障可能次数和选择可行的保护措施的方法。 二次故障不在本标准中考虑。 2 References 第二章 标准 The following Recommendations and other references contain provisions which, through reference 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: all users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. 以下文件中所包含的条款，通过本标准的引用，构成本标准的条款，对于注明日期的引用标准，任何一个版本的后续修订不适用于本版本。然而，鼓励本标准达成协议的各方考虑采用以下所示规范性文件的必威体育精装版版本。 [1] CCITT Recommendation K.29 (1992), Coordinated protection schemes for telecommunication cables below ground. K.29 地下通信电缆、光缆的综合保护方案。 [2] ITU-T Recommendation K.11 (1993), Principles of protection against overvoltages and overcurrents. K.11 过电压和过电流保护的原则 [3] ITU-T Recommendation K.39 (1996), Risk assessment of damages to telecommunication sites due to lightning discharges K.39 电信局站雷电放电的危险评估 3 Definitions 第三章 定义 This Recomm