High frequency non-intrusive electric device detection and diagnosis

The number of electronic devices in households as well as in industrial workplaces is continuously growing because of progress in automation. Identifying unusual operating behavior, detecting device failures in advance, and recognizing energy saving potentials are key features to improve the reliability, safety, and profitability of those systems. Facing these tasks, todays research is focused inter alia on a non-intrusive load monitoring approach, where the electrical signal is measured at a central point with modern hardware and processed by pattern recognition algorithms. Thus, we developed a smart meter prototype with a high sampling frequency, which allows for continuous measurement of the current and voltage from three-phase power lines. Besides this, in this paper we describe the usage of current-only measurement data (simple and safe installation using current transformers) with which we were able to classify state changes of a mobile air-conditioner with the help of Fourier descriptors as well as with additional voltage measurement.