Maintaining Heterogenous Electricity Infrastructure : A Multiple Case-Study of Swedish DSO Perceptions and the Adoption of Risk-Based Maintenance

Sammanfattning

Today's societal development poses several challenges for distribution system operators (DSOs) due to increasing electrification, implementation of modern technologies and aging infrastructure. Simultaneously, operators are expected to provide a continuous and steady supply of electricity to end-users at all times. In order to face these challenges and ensure the electricity supply upon which society depends, data-driven and risk-based maintenance approaches have gained increasing traction. This study’s purpose is to investigate the potential for maintenance management support tools in heterogeneous infrastructural systems. More specifically, the study attempts to assess the suitability of data-driven and risk-based approaches for Swedish DSOs and how certain asset characteristics together with operator experience influence maintenance needs. This is done by analyzing switchgear assets in a multi-case study of 7 DSOs and by using Great Britain’s framework, the Common Network Asset Indices Methodology (CNAIM), as a reference point. The empirical findings identified tacit knowledge as a main driver for maintenance and decision-making. Although the analyzed DSOs have implemented risk-based factors in their maintenance decision-making, this is done without a formal risk-based framework. On the contrary, network operators rely on tacit knowledge acquired through informal channels. The results indicate that age by itself is an insufficient variable for assessing maintenance as other factors, e.g. operational conditions, local environments and asset technology also play a vital role in determining asset health. The results also indicate that organizational factors served as obstacles for the implementation of more technologically advanced maintenance supporting tools. Data-scarcity and quality as well as fragmented information systems or financial resources were identified as the most prominent obstacles, although their severity depends on DSO size. On one hand, risk-based methodologies such as CNAIM are theoretically applicable for DSOs in Sweden since risk-based logic is already established in maintenance practices. On the other hand, a successful implementation of such a risk-based framework requires taking organizational heterogeneity into consideration as different DSOs face different limitations.