Reliability and availability comparison of energy chain architectures

Abstract

Abmacl -Reliability and availability calculation is a useful method used for energy chain architectures comparisons. In this work, a VRLA battery relisbility taking into account age, working temperature, tloating voltage regulation, and antouomy of the battery strings, is proposed. Others components Failures rates are gathered from the field. Then an availability calculation program for architectures, with and without generator, is developed. This program takes into account tbe used battery autonomy and the maintenance conditions of the energy station. Finally, reliability data with high level of inaccuracy are adjusted to fit observed unavailability results, during a five year period on francetelecom energy station populatiou. Based on tbis propam, a sensibility study is done to determine the influence of the battery autonomy and the maintenance conditions. Finally, battery autonomy rules are derived from this study, to fulfill a very common unavailability target of 5 mdyear with the minimum of maintenance conditions. The necessity for a back-up generator with a switchover system is also discussed depending on site power AC grid quality.

Analysis of wiring design for 380-VDC power distribution system at telecommunication sites

“…Another solution could be to centralize the battery by using AC type Uninterruptible Power Supply (ACUPS), as Marquet discussed [1], but the calculation for this architecture demonstrated that reliability is about the same for 48 as for 400 V and much better than for ACUPS solutions [2], [3], [4], [5], [6]. DC also offers an advantage in distribution simplification resulting in a decrease in the installation bill of material.…”