Reliability aspects of telecom powering with respect to the fibre-in-the-loop developments

Optical fibres in the local loop offer a greater bandwidth and henceforth more telecommunications services. The strategic role of powering the access network becomes more apparent. Factors related to the supply of power significantly define the availability of telecommunications services. Telecommunications power systems may have different configurations. This contribution details a method that uses the dominating factors of a certain configuration and determines how they affect reliability. The method is fairly simple because there is a way to avoid the standard but extensive Markov approach. Knowledge of the behaviour of the dominant failure mechanisms is combined with field experience. In fact, this method can be used for all types of powering in which secondary power sources such as emergency diesel generators are used together with an online energy reserve such as a battery. Not only the availability of power but also the coincidence effect with public power failures is important as well as the failure rate of a power system. Besides these evaluation methods, examples are given to show how this method can be applied given a certain mains power failure probability distribution. Based on this insight recommendations are given for powering an access network that uses optical fibres.