Back to Blog

microPMU Filter Mode Options

Today, we’re outlining the multiple filter options of our microPMU and their applications. Phase Measurement Units (PMUs) provide a high bandwidth window into electrical grid state and dynamics going beyond the capabilities of traditional SCADA systems. microPMU’s filter and isolate the grid waveform’s fundamental component and digitize it together with a GPS-derived time reference signal; the data (in the US) is streamed to Utilities for network control and analysis using the IEEE C37.118 protocol. PMUs enable precise amplitude and differential phase measurements (based on the GPS timestamp) across long distances, for example, mapping grid instabilities at a state or national level. Powerside’s microPMU accomplishes the same mission but with yet higher resolution and phase accuracy options, which are optimized for the cross-town distances and increasing complexity of electrical distribution systems.


PMU filter design is a tradeoff of competing parameters: measurement uncertainty and noise/harmonic rejection generally improve with more sophisticated filters, to the detriment of data latency. Monitoring dynamic events for detection and control applications, such as micro-grid islanding detection, favors simple, fast filters, resulting in the lowest data latency. On the other hand, precise impedance-based fault location based on complex tensor mathematics benefits from the best uncertainty and higher noise rejection filters with longer latency.

Our microPMU supports multiple filter types, including standard IEEE C37.118 M and P Class filters, and includes our proprietary high-resolution mode.

  C37.118 M & P Class Filters High precision filter
Type Low & moderate filtering
Moderate noise rejection
Complex filtering
High noise rejection
Typical Applications Islanding & Transient detection
ROCOF measurement
High bandwidth current-flow
Impedance modelling
Fault location
Typical Amplitude Resolution +/- 0.5 % < +/- 0.01 %
Typical Differential Phase Resolution +/- 0.5 o +/- 0.001 o
Filter Latency 50 ms 0.7 s
Streaming Rate 60 Hz 120 Hz

As microPMU’s are gaining adoption in distribution networks, the devices’ agility to perform more than one mission is critical. Powerside’s microPMU is a compact and cost-effective solution for diverse monitoring applications. It is being field-deployed with Tier 1 Utilities and supporting an expanding body of research applications.