Testing materials and devices for a specific failure mechanism usually yields a characteristic distribution of failure times. However, failure of power electronics (PE) can be due to a manifold of mechanisms. Even in a single PE device multiple failure processes may compete. For instance, modules may contain various components that fail according to different processes. When testing a batch of devices with competing processes, the resulting failure distribution is likely to consist of a combination of distributions, also called ‘entangled’ distributions. If processes compete, the time of failure according to the one process masks the time of failure according to a competing process. The observed failure time for one process leads to a so-called censored failure time of the competing process. If there is a balance between occurring failure processes, data analytics should not only involve the observed, but also the censored failure times. Another cause for distributions to blend, is the test of inhomogeneous test batches. For instance, some test objects may contain a production flaw, while other objects don’t. Such a mix of (sub) populations will also yield a total distribution consisting of entangled distributions. Enhanced stresses in a test are likely to accelerate the various aging processes at different rates. Awareness of distribution entanglement and acceleration is useful for interpreting test results and developing effective testing methods. The present contribution reviews the statistical analysis of R&D data. It discusses competing processes, mixed populations, censored failure data, accelerated aging, and how these phenomena affect analytics by graphical analysis and parameter estimation. Finally, series and parallel system configuration and reparability aspects are discussed.@en

The here reported work is part of a project on supporting grid resilience by asset management techniques. The present work focuses on support of decision-making after a few failures occurred that may be the start of many more. Methods are reviewed and new algorithms developed where the present IEEE/IEC standard does not provide. Two cases of early failures and wear-out are analyzed as examples for the data analytics.

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This paper discusses a method for data analysis of early failures that are typically due to defects from production and/or installation. The approach is based on Weighted Linear Regression and aims at estimating the next failure moment and the failure probability in an interval. As an additional goal, methods are intended to be suitable for light computing devices.@en

High current capability, good integration in urban area and zero external magnetic field are advantages of HTS cables that make them interesting for implementation in the Netherlands. So far experience with HTS cable projects is good, but still limited. Yet there is a need for a proper testing practice. Due to limited operational experience, various aspects remain to be studied. This paper focuses on electrical testing of electrical insulation, the application of power laws and the length effect. These issues are yet to be resolved, but the paper discusses their background and uncertainties. This may give direction to the ongoing studies in order to assure quality of HTS.@en