Reliability worth in distribution plant replacement programmes

Most of the distribution system plant in the United Kingdom was commissioned during the high growth years of the 50s and 60s and although some of this equipment may still be “operating satisfactorily”, most are approaching replacement need. The subject of asset replacement programmes is receiving an increased level of consideration and debate. However, since currently applied incremental cost savings may not always be sufficient to support a replacement programme, other benefits have to be made available to provide supplementary justification. This paper demonstrates that incremental power system customer outage costs fill this function best and should therefore be considered in cost-benefit analyses of distribution system asset replacement programmes.