Developing a System Vision of Assets at Elia, the Belgian Transmission System Operator

Abstract

This paper is about the latest developments to support risk management of assets at Elia, the Belgian transmission system operator operating the HV grid from 30 to 380 kV. The story of risks management within the company started more than 5 years ago, when a methodology was developed to assess the criticality for continuity of supply of individual assets. The output of this methodology is still used nowadays. As an example, maintenance policies do take into account the criticality of the asset on the network to define its maintenance frequency. So do replacement decisions. However, as many other TSO’s, Elia is also facing new challenges e.g. the energy revolution is pushing the ageing assets more and more to the limits. Scarcity in resources (both financial as in workforce) forces Elia to make sound and good decisions and prioritize actions despite uncertainties and scarceness of data. Risk management should help tackle these problems. In more concrete terms, there is a need for better addressing many diverse questions such as dealing with system redundancy, with the mutual impact of assets, with the impact of low voltage assets (protections) on high voltage assets, better assessing load at risk, asset end of life, the impact of a failure on several risk dimensions, the efficiency of risk mitigation measures, etc. In the frame of this paper, it was decided to focus on the solutions found to better assess the impact of protections on high voltage assets and the interaction between assets. To tackle these topics, one could think of implement- ing sophisticated methods such as probabilistic assessment, but this in turn requires asset reliability data, resources, skilled persons and lots of time for development, which are all sparse quantities. Therefore progress was made with pragmatic 80/20 methodologies, the 80/20 methodology is a free interpretation of the Pareto principle, stating that 80% of the results and valuable information come from 20% of the efforts which though not perfect, allows delivering valuable information. The corresponding developments are discussed in the frame of this paper.