TUCap: A Sensing System to Capture and ProcessAppliance Power Consumption in Smart Spaces

The collection of power consumption data from electrical appliances is a key enabling element for grid-related services such as load forecasting or anomalous consumption pattern detection. Device-level sensors (smart plugs) have found widespread use to collect such data. However, they prevalently report an electrical appliance’s power consumption at a rate of one reading per second. With mains voltage frequencies of 50/60 Hz, undersampling and the consequent loss of spectral information result from the use of such sensor devices. Moreover, most smart plugs only report readings of an appliance’s real power consumption. Important supplementary features like the phase shift between voltage and current or the magnitude of reactive power are not available for retrieval from commercially available devices. In this work, we overcome these limitations of smart plugs by presenting TUCap, an embedded sensing system to capture appliances’ electrical load signatures in minute detail. Our design caters to the provision of a high information content by capturing voltage and current waveforms at a sampling rate of 36 ksps. Thus, spectral components are implicitly included in collected traces. Moreover, TUCap uses local data processing routines to detect and eliminate redundancies. Thus, a high data fidelity is maintained while achieving significant reductions of network traffic. All functionalities are implemented in a proofof-concept system design and evaluated in practice.