Auditory Displays of Power Grids
As aging electric power systems continue to be transformed into modern smart grids, the amount of real-time measurements that are collected for monitoring and control applications has grown substantially. While critical to the realization of a future power grid that is more reliable, resilient, and efficient than ever before, this level of observability will lead to information overload and operator fatigue – unless the displays of these data are carefully designed. Traditionally, grid operators are presented with graphs, numbers, and alarm lights, some of which may be displayed dynamically on a system diagram and map. Such a visual display can easily become overcrowded.
Here at Union, we are investigating the use of auditory displays that will augment these visual displays. Auditory displays take advantage of the fact that the human listening system can effortlessly identify sound sources and perform pattern recognition, even in noisy conditions, in order to provide an additional means of communicating information to an operator. One commonly used technique for realizing an auditory display is “audification,” where data are directly played through a speaker. This is particularly challenging for power grid measurements due to their low-frequency nature. Instead, “sonification” may be used, whereby the data are used to control the parameters of an artificially synthesized sound.
One implementation of sonification simply amplifies power grid voltage magnitude and frequency variations so that they are detectable by the human ear, and then shifts the fundamental frequency up from 60 Hz to, e.g., the 440 Hz corresponding to an A note. The result, which can be heard below, is an otherworldly theremin-sounding noise. In this example, the power system is under ambient conditions up until about the 21-second mark, at which point a rogue oscillation caused by a malfunctioning generator appears in the data. This oscillation is clearly heard, and is detectable by the ear after only few seconds. In contrast, automated oscillation detection schemes can take on the order of minutes to trigger an alarm. These initial results are promising; ongoing work seeks to further develop and refine the auditory display so that it maximizes the transfer of relevant information while avoiding feelings of distraction and annoyance. This is fundamentally interdisciplinary and requires expertise from the power industry, human behaviorists, and music theorists alike.
Tonal Sonification of Voltage Magnitude and Frequency Under Ambient Conditions with a Forced Oscillation at 00:21
Power Pop!
A natural offshoot of this work has been to use the sonification platform to compose musical pieces that are entirely controlled by power grid measurements, which has provided an entertaining way to for electrical engineering and music students to learn about each others’ disciplines in a rather unexpected fashion. One may use, e.g., voltage magnitude and frequency sampled at various intervals to trigger the attack and pitch of MIDI piano keys. Or, one may use multiple time-aligned, geographically widespread voltage measurements to control several MIDI instruments. This results in a musical piece in which the orchestra is the power grid itself!
Musical Sonification of Voltage Magnitude and Frequency Under Ambient Conditions (MIDI piano)
Multichannel Musical Sonification of Voltage Magnitude and Frequency Under Ambient Conditions (MIDI multi-instrument)
For More Information…
This work was completed as part of Patrick Cowden’s 2017 senior capstone project, including the three audio snippets heard here. For more information, including additional audio tracks, please view our paper that was presented at the 24th International Conference on Auditory Display (ICAD 2018), June 10-15, 2018, Michigan Technological University, Houghton, MI, USA.
