Extended monitoring of electrical power needs to be done for power grids and inverter-driven electric machines to characterize their long-term behavior. Power systems will often experience a variety of events that can cause durability issues or failures in sub systems. Often, the reason for a sub system failure will be unknown, and measurements will need to be made over an extended period to identify the root cause so that engineering decisions can be made. Monitoring power for an extended period on an inverter-driven system can be difficult due to the required sampling rate needed to accurately measure electrical parameters.
An example of a monitoring test is the following five-day study done on an electric motor. In this test, motors were failing for an unknown reason. The test included recordings of the THD and RMS values of the phase currents and voltages, in addition to temperatures. This test was an initial investigation into the root causes of failure.
