1. EEL / UFSC The Brazilian Wide Area Measurement System – Experience and Applications Daniel Dotta email: dotta@ifsc.edu.br

2. EEL / UFSC u Objective u Wide Area Measurement System Overview u Phasor Measurement Process –Research going on at RPI u The MedFasee Project –LVPMS and HVPMS prototypes u Blackout in the Brazilian Interconnected Power System u Selected Applications u Conclusions Presentation Structure

3. EEL / UFSC u To present an overview of the Brazilian experience with Wide Area Measurement Systems Objective

4. EEL / UFSC Wide Area Measurement System - WAMS

5. EEL / UFSC Wide Area Measurement System Overview 5 u Simultaneous signals measurements at remote geographic locations using PMUs (Phasor Measurement Units). u GPS time synchronized measurements u Data acquisition and handling in remote sites (PDC). u Upgrade rate (scanning) >> SCADA. u Allows dynamic monitoring and control of electric systems. u New paradigm for the system operation.

6. EEL / UFSC Phasor Definition u Complex number that represents a sine wave whose amplitude (X) and angular frequency (ω) are time-invariant u The phasor module is equal to the rms signal value and the phase angle is the signal phase to t=0. 6

7. EEL / UFSC Synchrophasors  Phasor measurements that occur at same time are called “synchrophasors”. Task not trivial: Involves large distances and high time precision. 7 Necessity of only one time reference – Synchronization!

8. EEL / UFSC  Update rate: 30-60 phasors per second  Time synchronized data  High-speed communication links  Allows the dynamic system monitoring  Update rate: each 2-5 seconds  No time synchronization  Regular communication links  Allows stead-steaty system monitoring SCADA (Supervisory Control and Data Acquisition) WAMS (Wide-Area Measurement System) SCADA X WAMS (Comparasion) 8

9. EEL / UFSC u By SCADA u By WAMS How can the power system be seen? 9

10. EEL / UFSC Phasor Measurement Process

11. EEL / UFSC Basic Phasor Measurement Process Idea Sine Wave Window Size (points) Sampling rate For N=12 Sampling period Regular sampling period (Ts)

12. EEL / UFSC Basic Phasor Measurement Process Idea Time Domain Frequency Domain Samples where DFT

13. EEL / UFSC u Definition of DFT u Discrete Fourier Transform is a simple widely used method for phasor estimation –Other methods have been discussed »Kalman filters, weighted least squares and neural networks –Currently used in the commercial PMUs Phasor Estimation Fundamental frequency component, set m=1

14. EEL / UFSC Basic Phasor Measurement Architectures Frequency TrackingFrequency Compensation

15. EEL / UFSC u Composed basically by –Analogic and digital filters –Phasor Estimation Methodology –Frequency Estimation Methodology u The most explored and applied is the frequency compensation architecture –Basically because use uniform sampling period Basic Phasor Estimation Architecture

16. EEL / UFSC u Frequency Estimation is a key role in the both architectures –Changing the sampling window –Providing the frequency for phasor correction u Several methods are found in the literature –Zero Crossing –Least Error Squares –Kalman Filters –Demodulation –Phasor measurement angle changing Frequency Estimation (Methodologies)

17. EEL / UFSC u Under off-nominal operation the phasor measured (X mes ) is different from the true value (X true ) –The effect of the off-nominal frequency can be expressed by a P factor. Pos-Processing (Off-nominal Frequency) where N - window size w – actual frequency w 0 – nominal frequency Phasor correction

18. EEL / UFSC u The P factor is directly influence by N and frequency value u P behavior under frequency variation (N=48) Pos-Processing (Off-nominal Frequency)

19. EEL / UFSC u Frequency step (off-nominal operation) Phasor Estimation (Discrete Fourier Transform)

20. EEL / UFSC u Sequence positive phasor estimation Phasor Estimation (Discrete Fourier Transform)

21. EEL / UFSC MedFasee Project

22. EEL / UFSC Brazilian Interconnected Power System - BIPS u Main Characteristics –Capacity of about 100 GW –Predominant hydroelectric generation (about 71 %) –90000 km of transmission lines, with voltages ranging from 230 kV to 765 kV –The largest powerplant, Itaipu, has 20 generators with a generation capacity of 14 GW, half in 60 Hz and half in 50 Hz –Composed by 5 subsystems

23. EEL / UFSC u Project started in 2003 –The main goal was to develop the synchronized phasor measurement technology in Brazil and study its applications u It resulted in two prototypes currently installed in Brazil: –LVPMS (Low Voltage Phasor Measurement System). –HVPMS (High Voltage Phasor Measurement System). The MedFasee R&D Project

24. EEL / UFSC Medfasee Project (First Prototype) u Three PMUs were installed in laboratories of three universities in Southern Brazil u The PMUs measure the instantaneous three-phase distribution voltage u The PMUs have a network interface connected to the Internet to send the phasors to the PDC –60 phasors/s u The PDC is located in the Electrical System Planning Research Laboratory (LabPlan) at UFSC

25. EEL / UFSC u PMU UTFPR u PMU PUC – RS PMU e PDC  LabPlan – UFSC MedFasee Project – Low Voltage Prototype Installation Details 25

26. EEL / UFSC a) Frequency Evolution:b) Frequency Spectrum  System frequency oscillation mode ~ 0,02 Hz (period 50s). Frequency Monitoring (12/01/2005) 15h00min00s e 15h29min59s)

27. EEL / UFSC Firsts Disturbances Disturbance Southeast / Mid-West (14/03/2005 – 05h05min12s)

28. EEL / UFSC MedFasee Low Voltage Phase II - National WAMS  Characteristics  Develop, dissemination and educational use of the WAMS technology  Nine universities participate in the project  Five geographical regions are covered  Internet is used as commutation link 28

29. EEL / UFSC Source: www.medfasee.ufsc.br/temporeal

30. EEL / UFSC u PMU UFSC – Florianópolis, SC –Installation Date: 30/11/2008 MedFasee LV - Installations 30

31. EEL / UFSC u PMU UFPA, Belém, PA –Installation Date: 06/11/2008 31 MedFasee LV - Installations

32. EEL / UFSC u COPPE/UFRJ, Rio de Janeiro, RJ –Installation Date: 18/12/2008 32 Phase II -> Conclusion MedFasee LV - Installations

33. EEL / UFSC u Hardware: –DELL OptiPlex 755 –Core 2 Duo 3GHz, 2GB RAM, 2000 GB HD u Software: –Operation System - GNU/Linux + (RTAI) –Oriented Object Modeling (C/C++) –MySQL Database –Long-term historical database u Communication System: –Internet (VPN) MedFasee LV PDC Installation - UFSC 33

34. EEL / UFSC MedFasee LV– Phase III National Wide Area Measurement System 34 u Characteristics  Improve the national system coverage  14 universities involved  West BIPS monitoring

35. EEL / UFSC Source: www.medfasee.ufsc.br/temporeal

36. EEL / UFSC HVPMS (High Voltage Phasor Measurement System) –The HVPMS resulted from a partnership with Eletrosul, a transmission utility in Southern Brazil –Four PMUs, installed at Ivaiporã, Areia, Campos Novos and Nova Santa Rita 525 kV substations –Voltage and current phasors are sent to the PDC at a rate of 60 data frames per second –It has been monitoring eight transmission line terminals with two transmission lines having PMUs in both terminals

37. EEL / UFSC MedFasee Project Eletrosul PMUs  Digital Fault Recorder with PMU functionality  2 RPV 304 + 2 RPV 310  Standard IEEE C37.118  Rate 60 phasor/second - 3Ф  Link Ethernet and UDP/IP protocol  Configurable to 10, 12, 15, 20, 30 e 60 phasors/s e positive sequence RPV 304 RPV 310 37

38. EEL / UFSC Projeto MedFasee Eletrosul PDC  Characteristics:  PC architecture  GNU/Linux + (RTAI) operational system  Object Oriented Modeling (C/C++)  MySQL Database  Features:  Receiving, handling and re- synchronization of phasors  Centralized data available and storage  Support for off-line analysis  15 days historical database Hardware: Core 2 Duo 3GHz 2 GB RAM 250 GB HD 38

39. EEL / UFSC u An event, on March 21, 2009, is used to illustrate the correlation between the LVPMS and the HVPMS u Event Description –525 kV transmission line Lajeado-Miracema tripped; –900 MW generator shedding at Lajeado hydroelectric power plant; Data Correlation (LVPMS X HVPMS)

40. EEL / UFSC LVPMS x HVPMS (Frequency Behavior) LVPMSHVPMS High correlation between the recorded data

41. EEL / UFSC LVPMS x HVPMS (Angle Difference and Power Flow) Angular Difference UFSC (South) – USPSC (Southeast) LVPMS HVPMS Power Flow TL Ivaiporã- Areia Frequency Spectrum Ivaiporã is an Interconnection point between Southern and Southeastern regions

42. EEL / UFSC BIPS Blackout (November 10, 2009) –At 10:13:06 (PM), local time, the three 765 kV (AC) transmission lines that connect ITAIPU power plant to the BIPS tripped –The fault was caused by a sequence of three single-phase short-circuits in different phases, near Itaberá substation

43. EEL / UFSC u Itaipu real time operation BIPS Blackout (November 10, 2009)  The Itaipu power plant was operating with 18 generators, with a 5560 MW power flow over the AC link and a 5329 MW power flow over the HVDC transmission system

44. EEL / UFSC u Sequence and consequences of the Blackout BIPS Blackout (November 10, 2009)  Disconnection of the Itaipu AC transmission system  Overloading and tripping of transmission lines interconnecting the Southern and Southeastern subsystems  After two seconds, a cascating outage of power plants and transmission lines in the Southeastern region led to a voltage collapse and the tripping of the HVDC link  The disturbance spread to other parts of the BIPS  The blackout resulted in the interruption of approximately 25 GW, 40% of BIPS total load

45. EEL / UFSC u Recorded by the LVPMS –Voltage dipping, following the outage of the Itaipu AC transmission system and the South-Southeastern interconnections. BIPS Blackout (November 10, 2009) Voltage Collapse Southeastern subsystem USP-SC, COPPE and UNIFEI The voltages recover in the South (PUCRS, UFSC and UTFPR)

46. EEL / UFSC BIPS Blackout (Recorded by the LVPMS) Frequency excursions after the outage of the main South-Southeast interconnection Voltage HVPMS – Active Power Flow The 525 kV transmission line (Assis–Araraquara) keeps the Southern and Southeastern regions connected for 1min20s

47. EEL / UFSC u Asynchronous operation BIPS Blackout (Recorded by the LVPMS ) LVPMS – Zoom in asynchronous operation 63.6 Hz (Max) South 58.6 Hz (Min) North

48. EEL / UFSC u First South-Southeast reconnection –At 01:43:50 (AM), the first attempt to reclose de interconnection BIPS Blackout (Recorded by the LVPMS) Frequency Frequency Spectrum – North-South Mode

49. EEL / UFSC u The data captured by the both systems were very important to elucidate the Brazilian Blackout u Since than, the National System Operator have been use the Medfasee data to post- mortem disturbance analysis –Decrease the time spend in post-mortem analysis BIPS Blackout (November 10, 2009)

50. EEL / UFSC Selected Applications  Low-frequency oscillation mode detection  Model Validation  Transmission Line Parameters Calculation  Small-signal control

51. EEL / UFSC Model Validation Selected Study 51  BIPS disturbance  04/07/2009  Registers:  MedFasee LV  MedFasee Eletrosul  Simulation Model:  Anatem/CEPEL  Validation Analysis  Qualitative Validation  Quantitative Validation

52. EEL / UFSC Qualitative Validation Frequency Signal Assessment 52 u Medição - BT u Simulação - BT MeasuredSimulated LV HV

53. EEL / UFSC Real Time Spectral Analysis 53  MDF  Real-time applications  Off-line applications

54. EEL / UFSC Conclusions u The MedFasee project involves the development of equipment, installation, operation and performance analysis of Wide Area Measurement System (WAMS) u It is possible to get important information on the power system dynamic performance from the low-voltage WAMS. u The MedFasee project has been a rich experience and has contributed to the development and dissemination of WAMS technology in Brazil. u The WAMS represents a paradigm change in the power system monitoring u The WAMS measurement process must be simple and understandable for power system engineers u Improve the application of signal processing techniques in power system

55. EEL / UFSC Thank you! u Daniel Dotta –Department of Electrical Engineering – EEL –Federal Institute of Santa Catarina – IFSC –E-mail: dotta@ifsc.edu.brdotta@ifsc.edu.br –RPI contact –E-mail: dottad@rpi.edudottad@rpi.edu –Linkedin –http://www.linkedin.com/pub/daniel-dotta/11/79a/85bhttp://www.linkedin.com/pub/daniel-dotta/11/79a/85b