Managing PMU Data Sets with Bitmap Indexes

Large databases and data warehouses are becoming prevalent for the storage and management of energy data. Accelerating the rates at which data can be retrieved is beneficial not only to allow for more efficient search of the data, but also to be integrated with other energy system tools. In this paper, a fast indexing and data retrieval method, known commonly as a bitmap index, is created to facilitate intelligent querying and indexing of data generated by phasor measurement units (PMU) at a rate of 60 Hz. We find that bitmaps are amenable to managing efficient access to large amounts of PMU data. Furthermore, the bitmap-management process will provide decreased access time for data retrieval as well as decreased memory usage. From our experiments, our system is able to achieve approximately 30 times speedup on queries resulting in tuples that are in the database. Conversely, reducing the time taken to answer queries that result in tuples not contained in the database to nearly instantaneous.