Quantification of Disaggregation Difficulty With Respect to the Number of Smart Meters

A promising approach toward efficient energy management is non-intrusive load monitoring (NILM), that is to extract the consumption of appliances by analyzing the aggregated consumption signal. The large number of appliances and the presence of appliances with close consumption values are known to limit the performance of event-based NILM methods. To tackle these challenges, one could enhance the feature space which in turn results in extra hardware costs, installation complexity, and concerns regarding the consumer's privacy. This has led to the emergence of an alternative approach, namely semi-intrusive load monitoring, where appliances are partitioned into blocks and the consumption of each block is monitored via separate power smart meters. While a greater number of smart meters can result in more accurate disaggregation, it increases the monetary cost of load monitoring, indicating a trade-off that represents an important gap in this field. In this paper, we take a comprehensive approach to close this gap by establishing a so-called notion of "disaggregation difficulty metric (DDM)," which quantifies how difficult it is to monitor the events of any given group of appliances based on both their power values and the consumer's usage behavior. Thus, DDM in essence quantifies how much is expected to be gained in terms of disaggregation accuracy of a generic event-based algorithm by installing smart meters on the blocks of any partition of the appliances. Experimental results based on the REDD dataset illustrate the practicality of the proposed approach in addressing the aforementioned trade-off.