Dynamic Filter Compensator Schemes for Monitoring and Damping Subsynchronous Resonance Oscillations

1. Dynamic Filter Compensator Schemes for Monitoring and Damping Subsynchronous Resonance Oscillations Supervisor: Dr. A. M. Sharaf Electrical and Computer Engineering Department By: Bo Yin University of New Brunswick September 27, 2004

2. PRESENTATION OUTLINE • Introduction • Objectives • Background review of SSR • Modeling details for -Synchronous generators -Induction motors • Sample dynamic simulation results • Conclusions and future extensions

3. Introduction What is Subsynchronous Resonance (SSR)? Subsynchronous Frequency: • Subsynchronous resonance is an electric power system condition where the electric network exchanges energy with a turbine generator at one or more of the natural frequencies of the combined electrical and mechanical system below the synchronous frequency of the system. • Example of SSR oscillations: • SSR was first discussed in 1937 • Two shaft failures at Mohave Generating Station (Southern Nevada, 1970’s) Where: - Synchronous Frequency = 60 Hz - Electrical Frequency - Inductive Line Reactance - Capacitive Bank Reactance

4. Objectives 1. Study Subsynchronous Resonance (SSR) oscillations for synchronous generators and large induction motors 2. Explore a new method to monitor SSR shaft torsional oscillations 3. Develop and validate a novel dynamic control scheme to damp SSR shaft torsional oscillations

5. Background Review of SSR • SSR Torsional Modes Analysis -Mechanical System (inertia, shaft stiffness, etc.) -Electrical System • Mechanical test shows that the natural torsional modes as a function of inertia and shaft stiffness. • Torsional modes of frequency used in this study are between 11 and 45Hz. (typically 15.71Hz; 20.21Hz; 24.65Hz; 32.28Hz; 44.99Hz) • Categories of SSR Interactions: • Torsional interaction • Induction generator effect • Shaft torque amplification • Combined effect of torsional interaction and induction generator • Self-excitation • Torsional natural frequencies and mode shapes

6. Background Review of SSR • Other sources for excitation of SSR oscillations • Power System Stabilizer (PSS) • HVDC Converter • Static Var Compensator (SVC) • Variable Speed Drive Converter

7. Modeling for Synchronous Generator Sample Study System Figure 1. Sample Series Compensated Turbine-Generator and Infinite Bus System Figure 2. Turbine-Generator Shaft Model Table 1. Mechanical Data

8. Modeling for Synchronous Generator Figure 3. Matlab/Simulink Unified System Model for the Sample Turbine-Generator and Infinite Bus System

9. The Intelligent Shaft Monitor (ISM) Scheme Figure 4. Proposed Intelligent Shaft Monitoring (ISM) Scheme (Developed by Dr. A. M. Sharaf)

10. The Intelligent Shaft Monitor (ISM) Scheme - The result signal of (LPF, HPF, BPF) = 377 –Radians/Second T0 = 0.15 s, T1 = 0.1 s, T 2 = 0.1s, T3 = 0.02 s Figure 5. Matlab Proposed Intelligent Shaft Monitoring (ISM) Scheme with Synthesized Special Indicator Signals ( )

11. The Dynamic Filter Compensator (DFC) Scheme -Shunt Modulated Power Filter -Series Capacitor -Fixed Capacitor Figure 6. Facts Based Dynamic Filter Compensator Using Two GTO Switches S1, S2 Per Phase (Developed by Dr. A. M. Sharaf)

12. Control System Design Figure 8. DFC Device Using Synthesized Damping Signals ( ) Magnitudes

13. Control System Design Figure 7. Dynamic Error Tracking Control Scheme for the DFC Compensator (Developed by Dr. A. M. Sharaf)

14. Simulation Results for Synchronous Generator Figure 9. Monitoring Synthesized Signals without DFC Compensation Under Short Circuit Fault Condition

15. Simulation Results for Synchronous Generator Figure 10. SSR Oscillatory Dynamic Response without DFC Compensation Under Short Circuit Fault Condition

16. Simulation Results for Synchronous Generator Figure 11. Monitoring Synthesized Signals ( ) with DFC Compensation Under Short Circuit Fault Condition

17. Simulation Results for Synchronous Generator Figure 12. SSR Oscillatory Dynamic Response with DFC Compensation Under Short Circuit Fault Condition

18. Modeling Details for Induction Motor Figure 13. Induction Motor Unified System Model

19. The Dynamic Power Filter (DPF) Scheme Figure 14. Novel Dynamic Power Filter Scheme with MPF/SCC Stages (Developed by Dr. A. M. Sharaf)

20. Control System Design Figure 15. Tri-loop Dynamic Damping Controller (Developed by Dr. A.M. Sharaf)

21. Control System Design Figure 16. Tri-loop Error-Driven Error-Scaled Dynamic Controller Using a Nonlinear Tansigmoid Activation Function

22. Control System Design Figure 17. Proposed Tansigmoid Error-Driven Error-Scaled Control Block

23. Synthesized Monitoring Signals Where: Figure 18. Voltage Transformed Synthetic Signals Figure 19. Current Transformed Synthetic Signals

24. Simulation Results for Induction Motor Without Damping DPF Device With Damping DPF Device Figure 20. Monitoring Signals P & Q Figure 21.Monitoring Signals P & Q

25. Simulation Results for Induction Motor Without Damping DPF Device With Damping DPF Device Figure 22. Shaft Torque Oscillatory Dynamic Response Figure 23. Load Power versus Current, Voltage Phase Portrait

26. Summery: Three Cases Comparison Case 1 Case 2 Case 3 Figure 24. Monitoring SignalsWithout SSR Modes Figure 25. Monitoring SignalsWith SSR Modes But Without DPF Figure 26. Monitoring SignalsWith SSR Modes AndWith DPF

27. Summery: Three Cases Comparison Case 1 Case 2 Case 3 Figure 27. Monitoring SignalsWithout SSR Modes Figure 28. Monitoring SignalsWith SSR Modes But Without DPF Figure 29. Monitoring SignalsWith SSR Modes AndWith DPF

28. Summery: Three Cases Comparison Figure 30. Shaft Torque and Speed Dynamic Response without SSR Modes Case 1 Figure 31. Shaft Torque and Speed Dynamic Response with SSR Modes But without DPF Case 2 Figure 32. Shaft Torque and Speed Dynamic Response with SSR Modes And with DPF Case 3

29. Summery: Three Cases Comparison Figure 33. Stator Current Fast Fourier Transform (FFT) without SSR Modes Case 1 Figure 34. Stator Current Fast Fourier Transform (FFT) with SSR Modes but without DPF Case 2 Figure 35. Stator Current Fast Fourier Transform (FFT) with SSR Modes and with DPF Case 3

30. Conclusions and Future Extensions • For both synchronous generators and induction motor drives, the SSR shaft torsional oscillations can be monitored using the online Intelligent Shaft Monitor (ISM) scheme. The ISM monitor is based on the shape of these 2-d and 3-d phase portraits and polarity of synthesized signals • The proposed Dynamic Power Filter (DPF) scheme is validated for SSR torsional modes damping • Future work includes: • Develop a Matlab based monitoring software environment- the Intelligent Shaft Monitor (ISM) system for commercialization • Test a low power laboratory model of the prototype Dynamic Power Filter (DPF) and control scheme.

31. Publications [1] A.M. Sharaf; and Bo Yin; “Damping Subsynchronous Resonance Oscillations Using A Dynamic Switched Filter-Compensator Scheme,” International Conference on Renewable Energies and Power Quality (ICREPQ’04), Barcelona, March, 2004. [2] A.M. Sharaf; Bo Yin; and M. Hassan; “A Novel On-line Intelligent Shaft-Torsional Oscillation Monitor for Large Induction Motors and Synchronous Generators,” CCECE04, IEEE Toronto Conference, May, 2004. (Accepted)

32. Thank You & Question ?