Tag Archives: PMU

Appointed Co-Lead NASPI DisTT, News

Appointed co-lead of NASPI Distribution Task Team

May 2022

I am particularly happy and honored to join Daniel Dietmeyer from San Diego Gas & Electric in leading the Distribution Task Team (DisTT) at the North American Synchro Phasor Initiative (NASPI).

NASPI was founded in 2003 as the Eastern Interconnection Phasor Project, it is funded by the US Dept. of Energy, and is supported by the Pacific Northwest National Laboratory (PNNL) and the Electric Power Research Institute (EPRI). It is the largest collaboration of academics, industry practitioners and standardizing bodies for the development, use, understanding and promotion of methods and technologies based on synchronized measurements of voltage and current waveforms in power systems. These measurements with granularity of at least 30 per second and which are time synchronized via satellite across large grids, allow us to better analyze and control the stability and the security of the electrical grid.

Within the framework of DisTT, synchronized measurements enable the detection of faults, increase of hosting capacity of renewables, monitoring equipment health and others functions. At the current stage, DisTT focuses on the medium voltage beyond the substation.

This great opportunity and responsibility could not have been possible without the mentorship, support and inspiration that Sascha von Meier from UC Berkeley has gracefully offered me. I take over her role in leading DisTT in the hopes I can achieve half of what she did! Also, many thanks to Jeff Dagle (PNNL and chair of NASPI) for welcoming me on board.

 

IEEE TPWRS paper on fire-detecting digital twin of overhead line, News

IEEE TPWRS Paper on Digital Twin of Overhead Lines for Fire Detection

March 2022

Extending some of my previous work, I developed a digital twin for overhead conductors that detects an approaching forest fire and de-energizes the affected lines in a timely manner and not preemptively. The work has just been accepted in the IEEE Transactions on Power Systems (preprint here).

In California (CA) and elsewhere, the risk of overhead conductors igniting forest fires or adding seats to on-going ones is very real and extensive. In CA, PG&E’s overhead conductor equipment was determined to be the reason for the 2018 Camp fire, leading to law suits that caused the utility’s bankruptcy. After restructuring, the company updated its practices with preemptive disconnections of large parts of its grid during days of high risk of fire. The new practice disrupted service to thousands of customers, in most cases unnecessarily. Hundreds of new suits threatened PG&E with a second bankruptcy in 3 years.

Phasor Measurement Units (PMUs) have been widely adopted across grids. PMUs may be installed along a line in distances as close as a 1-2 miles in between. This gives rise and basis to the idea of real-time monitoring of line impedance for any reasons of variation. As resistance increases with ambient temperature (not proportionally), steep decreases in the inductance/resistance ratio (tangent of the impedance phasor – tanδ in the figure) of an overhead conductor may indicate that a forest fire burns near said conductor and it should, thus, be disconnected.

Behavior of moving average of impedance phasor as a forest fire approaches an overhead conductor and affects its resistance. Such a behavior should control the disconnection of this conductor.

The in silico testing under numerous worst case scenario conditions (no solar heating effect, broad measurement error intervals, synchronization errors, etc.), showed that the proposed method detects some cases of a forest fire approaching a conductor, in sub-second times and at extremely low false positive rates. In the next steps, I plan a collaboration with interested utilities and the US Forest Service for field testing.

I want to thank CMU ECE’s MSc student (at that time) and co-author Uday Sriram for his help in setting up the tests, Dan Dietmeyer from SDG&E for informing me about PMU deployments in CA, Farnoosh Rahmatian from NuGrid Power for lending his expertise on instrument transformers and Jeff Dagle from PNNL for his crucial comments in the earlier stages of this work.

News, PMUs and Inverters Panel IEEE SGSMA 2022

Panel on Synchrophasors in Zero Inertia Grids at the IEEE SGSMA 2022

February 2022

I am grateful to the Technical Program chairs of the 2022 IEEE International Conference on Smart Grid Synchronized Measurements and Analytics (SGSMA 2022) for accepting our panel proposal titled “Towards a Zero Inertia Grid thanks to Synchrophasor Measurements”. I have been delighted to have Prof. Yilu Liu (University of Tennessee at Knoxville), Dr. Evangelos Farantatos (EPRI),  Dr. Deepak Ramasubramanian (EPRI, on behalf of UNIFI), Dr. Qiteng Hong (University of Strathclyde, Glasgow) and Dr. Krish Narendra (Electric Power Group) accept my invitations to join this panel and contribute their expertise and experiences on the matter.

What we will be talking about revolves around how the electrical grid shifting to renewables and batteries, entails the shift to resources interfacing with the power system via power electronics – inverter, rectifiers and converters. As these devices and the sources they interface are characterized by fast dynamics, the traditional control paradigm followed to the day cannot suffice. The reason is that the phenomena that used to span seconds (thanks to large rotating inertias of conventional generators), will now be unfolding in milliseconds. Hence, the operators’ response times in the control rooms will be very limited. Thankfully, synchrophasors and the applications they enable can match these time-frames and allow for the transition to a new control paradigm.

I look forward to the conference and hope to be attending it in person in the beautiful town of Split in Croatia.