Experience feedback and maintenance policies of substations and electrical equipment in EDF's distribution MV and LV networks, and RTE's VHV and HV networks

The aim of this paper is to present aspects of the maintenance policies of substations and electrical equipment, and experience feedback method in the EDF's distribution network (MV and LV) and the RTE's network (VHV, HV). EDF has tested reliability-centered maintenance (RCM), with a view to improving EDF maintenance policies and adapting them to the company's new goals of improving supply safety and controlling cost. After an initial investigatory period, RCM was systematically carried out on all EDF's nuclear power plants. In the light of this experience, EDF committed itself in 1996 to a pilot study on a line bay of a 400 kV substation. The aim of the investigation was not only to test the feasibility of RCM, but more importantly to adapt it to substation equipment and operating conditions. Among others things, the problem presented in this paper include difficulties of estimating the cost of the consequences of failure, the gains in terms of reduced maintenance and the calculation of failure rates broken down by subcomponent. RTE has undertaken the generalization of RCM as part of its substation maintenance policy. Statistical analysis of the experience feedback reports could be used to determine the optimum period for refurbishing the electrical equipment. The aim of this analysis is to obtain the "bath-tub" curve of the equipment's failure rate. Two examples of applications are shown on MV lines and city street lamps