Stress Dependent Economic Assessment of Innovations in Power Substations

When a power utility considers the introduction of a new component in their substation, it is primarily faced with costs. Each proposed investment must be defended facing the management. In the simplest situation a new component with higher performance will just be substituted for an older one. In this case the existing methodologies are sufficient to assess the economic impact of the investment. In many cases a simple comparison is not possible because the new substituted component has very different properties or because the innovation is simply added to the substation, thereby increasing substation complexity. For these cases the costs caused by innovation must be justified by the overall benefits brought to the substation. A methodology for the evaluation and the calculation of the financial impact of a modification in power substations is presented in this work. The new idea compared to the conventional cost calculation methodologies is that the life-cycle costs of power apparatus are evaluated in dependence of the stresses effecting an apparatus. The overall economic impact of an innovation is calculated by investigating its implications on the various apparatus of the substation. When subjected to certain stress conditions during a period of time, the new apparatus may have slight damage. The consequence is that an increased probability of failure compared to the initial state is possible. Subjected again to new stresses, the apparatus condition gets even worse, with an increased risk of failure. If no maintenance is performed this process leads soon or later to the end-of-life of the apparatus. A mathematical model for the description of such a life cycle is described in this work. The model is based on the identification of all possible condition-states of an