APPLICATIONS OF GPS IN POWER ENGINEERING

1. APPLICATIONS OF GPS IN POWER ENGINEERING

2. What is GPS? • GPS or Global Positioning Systems is a highly sophisticated navigation system developed by the United States Department of Defense. This system utilizes satellite technology with receivers and high accuracy clocks to determine the position of an object.

3. The Global Positioning System • A constellation of 24 high-altitude satellites

4. GPS is • A constellation of satellites, which orbit the earth twice a day, transmitting precise time and position (Latitude, Longitude and Altitude) Information. • A complete system of 21 satellites and 3 spares.

5. GPS at Work • Navigation - Where do I want to go? • Location - Where am I? 3. Tracking - Monitoring something as it moves 4. Mapping - Where is everything else? 5. Timing - When will it happen?

7. Why do we need GPS? • Safe Travel • Traffic Control • Resource Management • Defense Mapping • Utility Management • Property Location • Construction Layout

8. 4 ‘birds’ (as we say) for 3-D fix

9. Global Positioning Systems (GPS) Applications in Power Systems

10. Power companies and utilities have fundamental requirements for time and frequency to enable efficient power transmission and distribution. Repeated power blackouts have demonstrated to power companies the need for improved time synchronization throughout the power grid. Analyses of blackouts have led many companies to place GPS-based time synchronization devices in power plants and substations

11. Why GPS For power Eng It furnishes a common-access timing pulse which is accurate to within 1 microsecond at any location on earth. A 1-microsecond error translates into 0.021° for a 60 Hz system and 0.018 ° for a 50 Hz system and is certainly more accurate than any other application

12. GPS time synchronization By synchronizing the sampling processes for different signals – which may be hundreds of kilometers apart – it is possible to put their phasors in the same phasor diagram

13. V1 V V1 V2 Ψ Substation 1 V2 • FFT or any other technique gives: • Magnitude • Phase angle • With respect to GPS V Substation 2 t1 t2 t3 t4 t5 t6 t7 GPS time synchronized pulses GPS time synchronization

14. Absolute Time Reference Across the Power System

15. Phasor Measurement Units PMUs Synchronized phasor measurements (SPM) have become a practical proposition. As such, their potential use in power system applications has not yet been fully realized by many of power system engineers.

16. Phasor Measurement Units (PMU) [or SYNCHROPHASORS]

17. DAWN OF THE GRID SYNCHRONIZATION

18. Phasor Measurement Units PMUs Phasor Measurement Units )PMU) They are devices which usesynchronization signals from the global positioning system (GPS) satellites and provide the phasor voltages and currents measured at a given substation.

19. Phasor Measurement Units PMUs PMU input output Corresponding Voltage or Current phasors Secondary sides of the 3Φ P.T. or C.T.

20. Phasor Monitoring Unit (PMU) Hardware Block Diagram:

21. Sampling at Fixed Time Intervals Using an Absolute Time Reference

22. The GPS receiver provides the 1 pulse-per-second (pps) signal, and a time tag, which consists of the year, day, hour, minute, and second. The time could be the local time, or the UTC (Universal Time Coordinated). The l-pps signal is usually divided by a phase-locked oscillator into the required number of pulses per second for sampling of the analog signals. In most systems being used at present, this is 12 times per cycle of the fundamental frequency. The analog signals are derived from the voltage and current transformer secondary's.

23. Computer Relaying developments in 1960-70s. The Birth of the PMUs ABB

24. Now SEL-421 RES 521 ABB

25. Phasor Measurement Unit’s

26. central data collection Phasor Measurement Units PMUs

27. Data Concentrator (Central Data Collection) ABB

28. Different applications of PMUs in power system

29. Applications of PMU in power System • Adaptive relaying • Instability prediction • State estimation • Improved control • Fault recording • Disturbance recording • Transmission and generation modeling verification • Wide area Protection • Fault location

30. Applications of PMU in power System 1-Adaptive relaying Adaptive relaying is a protection philosophy which permits and seeks to make adjustments in various protection functions in order to make them more tuned to prevailing power system conditions

31. Applications of PMU in power System 2-Instability prediction • The instability prediction can be used to adapt load shedding and/or out of step relays. • We can actually monitor the progress of the transient in real time, thanks to the technique of synchronized phasor measurements.

32. Applications of PMU in power System 3-State estimation • The state estimator uses various measurements received from different substations, and, through an iterative nonlinear estimation procedure, calculates the power system state. • By maintaining a continuous stream of phasor data from the substations to the control center, a state vector that can follow the system dynamics can be constructed. • For the first time in history, synchronized phasor measurements have made possible the direct observation of system oscillations following system disturbances

33. Applications of PMU in power System 4-Improved control • Power system control elements use local feedback to achieve the control objective. • The PMU was necessary to capture data during the staged testing and accurately display this data and provide comparisons to the system model. • The shown figure shows a typical example of one of the output plots from the PMU data

34. Applications of PMU in power System 5-Fault Recording • They can capture and display actual 60/50 Hz wave form and magnitude data on individual channels during power system fault conditions.

35. Applications of PMU in power System 6-Disturbance Recording • Loss of generation, loss of load, or loss of major transmission lines may lead to a power system disturbance, possibly affecting customers and power system operations.

36. Applications of PMU in power System Disturbance Recording These figures are examples of long-term data used to analyze the effects of power system disturbances on critical transmission system buses.

37. Applications of PMU in power System 7-Transmission and Generation Modeling Verification • Computerized power system modeling and studies are now the normal and accepted ways of ensuring that power system parameters have been reviewed before large capital expenditures on major system changes. • In years past, actual verification of computer models via field tests would have been either impractical or even impossible • The PMU class of monitoring equipment can now provide the field verification required

38. Applications of PMU in power System 7-Transmission and Generation Modeling Verification • The shown figure compares a remote substation 500 kV bus voltage captured by the PMU to the stability program results

39. The introduction of the Phasor Measurement Unit (PMU) has greatly improved the observability of the power system dynamics. Based on PMUs, different kinds of wide area protection, emergency control and optimization systems can be designed 8-Wide – Area protection Applications of PMU in power System

40. Applications of PMU in power System 9-Fault Location A fault location algorithm based on synchronized sampling. A time domain model of a transmission line is used as a basis for the algorithm development. Samples of voltages and currents at the ends of a transmission line are taken simultaneously (synchronized) and used to calculate fault location.

41. Applications of PMU in power System PMU A Synchronized phasor PMU B Synchronized phasor Modal Transform of synchronized samples Fault Location The Phasor measurement units are installed at both ends of the transmission line. The three phase voltages and three phase currents are measured by PMUs located at both ends of line simultaneously

42. SPM-based applications in power systems • off-line studies • real-time monitoring and visualization • real-time control, protection and emergency control

43. SOME RESEARCH PROGECTS (I participated in)

44. Global Positioning System (GPS)-Based Synchronized Phasor Measurement By Eng. Marwa M. Abo El-Nasr Supervised by Prof. Dr. Mohamed M. Mansour Dr. Said Fouad Mekhemer

45. CONCLUSIONS • The conclusions extracted form the present work can be summarized as follows: • A technique for estimating the fault location based on synchronized data for an interconnected network is developed and implemented using a modal transform • One-bus deployment strategy is more useful than tree search for fault location detection as it gives more system observability

46. 3- The average value of mode 1 and 2 of Karrenbauer transformation is used for 3-phase and line-to-line faults, while the average value of the 3 modes is used for line-to-line-ground and line-to-ground faults 4- The results obtained from applying the developed technique applied to a system depicted from the Egyptian network show acceptable accuracy in detecting the fault and locations of different faults types. Conclusions

47. STATE ESTIMATION AND OBSERVABILITY OF LARGE POWER SYSTEM USING PHASOR MEASUREMENT UNITS

48. Essence: This thesis is to address three issues: 1- Optimal allocation of Phasor Measurement Units (PMUs) using Discrete Particle Swarm Optimization (DPSO) technique. 2- Large scale power system state estimation utilizing the optimal allocation of PMUs based on Global Positioning Systems (GPS). 3- Power system voltage stability monitoring based on the allocated PMUs’ readings.

49. Wide Area Protection System for Maximizing Power System Stability Prepared By Fahd Mohamed Adly Hashiesh Under Supervision of Prof. Dr. M. M. Mansour Dr. Hossam Eldin M. Atia Dr. Abdel-Rahman A. Khatib Cairo – Egypt 2006

50. Research Objective Propose a protection system (strategy) to counteractwide area disturbance (instability), through employing adaptive protection relays, and fast broadband communication through wide area measurement. Configure and adapt the proposed system to be applied on Egypt wide power system network.