phasor measurement unit

phasor measurement unit
Name	Phasor Measurement Unit
Caption	Synchronized phasor measurements in a power grid
Introduced	1980s
Application	Power system monitoring, protection, control

Contents

phasor measurement unit

A phasor measurement unit provides time-synchronized measurements of alternating current and voltage phasors for electric power systems, enabling wide-area situational awareness and real-time stability assessment. Developed through collaborations among institutions such as National Renewable Energy Laboratory, Lawrence Berkeley National Laboratory, Electric Power Research Institute, and utilities like Pacific Gas and Electric Company and Bonneville Power Administration, the device leverages global navigation satellite systems and digital signal processing to produce high-resolution data streams. Early deployments were influenced by events analyzed by organizations including North American Electric Reliability Corporation, Federal Energy Regulatory Commission, and investigative studies following incidents like the Northeast blackout of 2003.

Introduction

PMUs measure synchronized phasors using precise timing references such as Global Positioning System, enabling coherent comparison across substations, transmission corridors, and interconnections managed by entities like Independent System Operator New England, California Independent System Operator, and Electric Reliability Council of Texas. Research programs at Massachusetts Institute of Technology, University of Illinois Urbana-Champaign, and Princeton University contributed fundamental algorithms, while manufacturers and vendors including Schweitzer Engineering Laboratories, Siemens, and General Electric produced commercial units. Regulatory and industry groups such as Institute of Electrical and Electronics Engineers, International Electrotechnical Commission, and North American SynchroPhasor Initiative guided early adoption.

PMUs compute phasors by sampling analog signals with analog-to-digital converters and applying discrete Fourier transform or Kalman filtering methods developed in part at University of California, Berkeley, Cornell University, and Imperial College London. Timing synchronization is achieved using receivers compatible with GLONASS, Galileo (satellite navigation), and BeiDou alongside Global Positioning System constellation timing, with time-stamping standards influenced by National Institute of Standards and Technology policies. Data aggregation occurs in Phasor Data Concentrators implemented at control centers operated by New York Independent System Operator, PJM Interconnection, and Midcontinent Independent System Operator, using communication infrastructures provided by vendors such as Cisco Systems and standards from IEEE Standard Association.

PMU outputs are applied to transient stability assessment for interconnections like the Eastern Interconnection and Western Interconnection, oscillation detection in systems monitored by Alstom Grid and Hitachi Energy, adaptive protection schemes used by American Electric Power, and state estimation enhancements at utilities such as Duke Energy and Exelon Corporation. Additional use cases include islanding detection in microgrids researched at National Renewable Energy Laboratory, renewable integration studies at Iberdrola and Ørsted, and oscillatory mode analysis relevant to large generating plants operated by Tennessee Valley Authority and Berkshire Hathaway Energy.

Interoperability and data models rely on standards from Institute of Electrical and Electronics Engineers including IEEE C37.118 for synchrophasor measurement, communication protocols influenced by IEC 61850 frameworks, and cybersecurity guidance from National Institute of Standards and Technology and North American Electric Reliability Corporation Critical Infrastructure Protection standards. Data exchange formats and architectures are addressed by initiatives from North American SynchroPhasor Initiative and compliance testing performed by laboratories at Pacific Northwest National Laboratory and Argonne National Laboratory.

Deployment strategies have been executed by regional transmission organizations such as PJM Interconnection, California Independent System Operator, and national utilities like Hydro-Québec and State Grid Corporation of China. Implementation involves integrating PMUs at substations produced by manufacturers including Schneider Electric, ABB, and Siemens Energy and connecting to Phasor Data Concentrators running software from OSIsoft and research prototypes from Rensselaer Polytechnic Institute. Training and workforce development efforts have engaged universities such as Virginia Tech and University of Texas at Austin and consulting firms like Accenture and McKinsey & Company for roadmap planning.

Challenges include ensuring measurement accuracy under weak-signal or harmonic-rich conditions studied at Argonne National Laboratory and Eindhoven University of Technology, maintaining resilience of timing references against interference and spoofing incidents investigated by Johns Hopkins University Applied Physics Laboratory, and managing large-scale data volumes for control centers like those at PJM Interconnection and National Grid plc. Interoperability issues, firmware vulnerabilities, and supply-chain constraints involve coordination with standards bodies such as International Electrotechnical Commission and regulatory agencies including Federal Energy Regulatory Commission.

Future directions involve enhanced algorithms from research groups at Massachusetts Institute of Technology, ETH Zurich, and Technical University of Munich for dynamic state estimation and machine learning applications supported by collaborations with Google DeepMind and Microsoft Research. Integration with distributed energy resources owned by companies like Enel and Vestas and cybersecure timing alternatives explored with partners including European Space Agency and National Institute of Standards and Technology aim to expand PMU capabilities. Continued international cooperation among North American SynchroPhasor Initiative, CIGRÉ, and IEEE Power & Energy Society will shape deployment, standards, and operational practices.

Category:Electrical engineering Category:Power engineering Category:Instrumentation