Traceability of Synchrophasor Measurements in Power Systems: Definitions and Methods

Date: Monday, May 24                               Time:  – 

Abstract: The tutorial investigates the main theoretical and technological aspects related to the rigorous definition and characterization of synchronized phasor measurements.

Extended abstract: can be found here: A. Goldstein, G. Frigo, “Determination of Digitizer Absolute Phase Using Equivalent Time Sampling”

In this sense, the tutorial consists of three sections:

Section 1 Prof. Pegoraro – The first Section introduces the mathematical definition of the measurand, namely synchrophasor, frequency and rate of change of frequency, and discusses their possible application in power systems’ monitoring and control applications. In this context, we present the importance of the measurement model, by illustrating alternative estimation approaches that rely on static and dynamic phasor model. The sources of uncertainty in the PMU measurement chain are discussed highlighting the pros and cons of each approach and focusing on estimation accuracy in standard and real-world operating conditions.
Section 2 Dr. Frigo – The calibration of phasor measurement units (PMUs) and the improvement of the associated normative documents are key points to support the deployment of such devices in the power systems. In particular, the rigorous and traceable metrological characterization of PMUs is still an open issue for national metrological institutes. In this Section, we describe the software and hardware architecture of the PMU calibrator currently being developed at the Swiss Federal Institute of Metrology (METAS). In particular, we characterize the uncertainty sources related to the voltage and current signal chains, and discuss the role of different time and frequency sources. 
Section 3 Dr. Goldstein – The rigorous characterization of the “absolute phase” in digitization systems still represents an open issue for national metrological institutes, research laboratories and manufacturers. In this Section, we present a new method for the determination of absolute phase, based on curve fitting a model of a filtered square wave, in order to determine its phase related to the phase of a sampled sine wave at the same frequency. The Equivalent Time Sampling (ETS) technique is used to capture the shape of the filtered rising and falling edges of the signal and the ETS captured signal is modeled. The proposed method should enhance the time resolution of the absolute phase determined for each system component. Taking as device under test the NIST PMU calibration system, we carry out an experimental validation and are able to determine correction factors for phase reference values with a worst-case uncertainty in the order of few microradians at 50 Hz.

Name and title of the organizer: Dr. Guglielmo Frigo 
Organisation: Swiss Federal Institute of Metrology (METAS), 3003 Bern-Wabern, Switzerland
Short biography of the chair: Guglielmo Frigo was born in Padua, Italy, in 1986. He received the B.Sc. and M.Sc. degrees in biomedical engineering from the University of Padova in 2008 and 2011, respectively, and the Ph.D. degree from the School of Information Engineering in 2015, with a dissertation about compressive sensing (CS) theory applications to instrumentation and measurement scenario. He served as PostDoc researcher at the Electronic Measurement Research Group, University of Padova (2015-2017), and at the Distributed Electrical Laboratory, Swiss Federal Institute of Technology of Lausanne (2018-2020). In 2020 he was foreign guest researcher at NIST, Gaithersburg, USA and he is currently scientist at METAS, Wabern, Switzerland. His current research interests include the development of enhanced measurement infrastructures for electrical systems.

Name and title of the organizer: Dr. Allen Goldstein
Organisation: National Institute for Standards and Technology (NIST), Gaithersburg, MD, US
Short biography of the chair: Allen Goldstein was born in Brooklyn New York, 1957, B.S. electrical engineering, University of Southern California, Los Angeles, CA, 1982. He enlisted in the U.S. Navy in 1976, served as an aviation electronics technician in 1982, served as a Navy Submarine officer. 1987, joined Peavey Electronics, Meridian, MS, as a Digital Design Engineer designing products utilizing draft international standards MIDI and Digital Audio while contributing to the drafting of those standards. Also did graduate coursework at the University of Mississippi. 1992, Director of Engineering at Symetrix, Inc. in Seattle, WA, leading design of high speed, high resolution A/D and D/A converters as well as DSP equipment. 1997 joined Digital Harmony, architected A/V ASIC compliant with draft IEEE 1394 (Firewire) while contributing to the drafting of that and related 1394 standards. 2004, he became Chief Architect at Numark, Incorporated’s Seattle design center, designed products based on the ASIC architected at Digital Harmony. 2006, worked as an electronics design consultant, designing an early PVR system, a digital audio analysis system, and several other digital audio/video products. In 2008, after seeing Al Gore’s “An Inconvenient Truth,” switched fields to work on electrical power equipment and standards, working on a “smart” micro-inverter, and with Fluke Calibration to lead the design of the first commercially available PMU calibration system. In 2012, joined NIST and presently works in the Synchrometrology Laboratory, the NIST Smart Grid Testbed and with IEC and IEEE. Allen is vice-chair of the joint IEEE/IEC working group for synchrophasor performance standard, IEEE/IEC TC95 JWG1, chair of the IEEE Conformity Assessment Program (ICAP) Synchrophasor Conformity Assessment Committee, and chair of IEC PSRC WG C28 requirements of PMU performance.

Name and title of the organizer: Prof. Paolo Attilio Pegoraro
Organisation:University of Cagliari, Electrical and Electronic Engineering Dept., Cagliari, Italy
Short biography of the chair: Paolo Attilio Pegoraro received the M.Sc. (summa cum laude) degree in telecommunication engineering and the Ph.D. degree in electronic and telecommunication engineering from the University of Padova, Padua, Italy, in 2001 and 2005, respectively. From 2015 to 2018 he was an Assistant Professor with the Department of Electrical and Electronic Engineering, University of Cagliari, Cagliari, Italy, where he is currently Associate Professor. He has authored or co-authored over 110 scientific papers. His current research interests include the development of new measurement techniques for modern power networks, with attention to synchronized measurements and state estimation. Dr. Pegoraro is a member of IEEE Instrumentation and Measurement Society TC 39 (Measurements in Power Systems) and of IEC TC 38/WG 47 (Evolution of Instrument transformer requirements for the modern market). He is an Associate Editor of the IEEE Transactions on Instrumentation and Measurement.