1. Thesis co-directors M. Paolone, F. Rachidi Distributed Electrical System Laboratory – DESL http://desl-pwrs.epfl.ch Reza Razzaghi Real-Time Simulation of Power Systems for Smart Grids Protection and Control

2. Outline o Introduction Motivation State-of-the-art o FPGA-based real-time simulator for power systems Optimal selection of switch parameter FPGA-based real-time simulator o Fault location in transmission lines using EMTR Time reversal process Experimental validation Simulation case studies 1

3. Outline o Introduction Motivation State-of-the-art o FPGA-based real-time simulator for power systems Optimal selection of switch parameter FPGA-based real-time simulator o Fault location in transmission lines using EMTR Time reversal process Experimental validation Simulation case studies 2

4. Smart Grids Progressive installation of distributed energy resources (DERs) Evolution of distribution networks passive active Planning Operation Control Challenges Distribution network protection and fault location Optimal voltage and power flow controls Introduction Motivation 3 Real-time monitoring and control functionalities

5. Introduction Problem Definition 4 Electromagnetic transient simulation plays an important role in the control, and operation of modern power systems. Offline Real-time The perspective use of real-time digital simulators (RTDSs) appears a promising solution for the development of a new category of dedicated Intelligent Electronic Devices (IED).

6. Introduction State-of-the-Art 5 Existing real-time simulators are based on various types of processors: General purpose processors (GPPS) Digital signal processors (DSPs) Computer clusters However, existing real-time simulators have limitations such as: Lower-bound limitation of the minimum simulation time-step Limitation in simulation of high frequency phenomena (power converters, short transmission lines) Inherent complexity of the hardware architecture characterized by several layers each one devoted to a specific function (i.e. A/D and D/A conversions, CPU computation, data transfer and storage, etc.). FPGA-based real-time simulators

7. Introduction State-of-the-Art 6

8. 7 FPGA-based real-time simulator FPGA-based real-time simulator for electromagnetic transients study of power electronics [5] FPGA-based real-time simulator for electromagnetic transients study of AC machines [17] FPGA-based real-time simulator for electromagnetic transients studies of power systems including transmission lines [7] Classical nodal analysis Lumped elements Classical nodal analysis Not-fixed admittance matrix Fixed Admittance Matrix Nodal Method (FAMNM) Transmission lines model

9. Outline o Introduction Motivation State-of-the-art o FPGA-based real-time simulator for power systems Optimal selection of switch parameter FPGA-based real-time simulator o Fault location in transmission lines using EMTR Time reversal process Experimental validation Simulation case studies 8

10. 9 1- Network solution method Modified nodal analysis (MNA) State-space method 2- Numerical integration method Trapezoidal method Euler methods 3- Network components model Lumped elements (R,L,C,…) Transmission lines FPGA-based real-time simulator for power systems

11. 10 Methodology Modified nodal analysis (MNA)

12. FPGA-based real-time simulator for power systems 11 Methodology Fixed Admittance Matrix Nodal Method (FAMNM) system nodal matrix remains unchanged during switching transitions Pejovic, P.; Maksimovic, D, A Method for Fast Time-Domain Simulation of Networks with Switches, IEEE Trans. Power Electron. 1994, 9, 449–456.

13. FPGA-based real-time simulator for power systems 12 Optimal selection of discrete-time switch model

14. FPGA-based real-time simulator for power systems 13 Optimal selection of discrete-time switch model Objective function Error function Losses function

15. FPGA-based real-time simulator for power systems 14 Optimal selection of discrete-time switch model

16. FPGA-based real-time simulator for power systems 15 Optimal selection of discrete-time switch model

17. FPGA-based real-time simulator for power systems 16 System configuration

18. FPGA-based real-time simulator for power systems 17 Proposed algorithm for FPGA-based real-time simulator

19. FPGA-based real-time simulator for power systems 18 Application example Line ParameterPhase aPhase bPhase c DC resistance0.018 /km Outside diameter5.626 cm Horizontal distance-7.4 m 0 m7.4 m Vertical height at tower28.5 m 29.5 m28.5 m Vertical height at midspan 28.5 m29.5 m28.5 m Simulation time step: 4 s

20. FPGA-based real-time simulator for power systems 19 Application of the FPGA-based real-time simulator joined with the EMTR Fault Location

21. Outline o Introduction Motivation State-of-the-art o FPGA-based real-time simulator for power systems Optimal selection of switch parameter FPGA-based real-time simulator o Fault location in transmission lines using EMTR Time reversal process Experimental validation Simulation case studies 20

22. FPGA-based real-time simulator for power systems 21 Fault location in power systems transmission lines Transmission system: Power system security Distribution system: Power system quality Fault location methods: i) Analysis of pre- and post-fault voltage/current phasors ii) Analysis of fault-originated electromagnetic transients of currents and/or voltages Active distribution networks: Electromagnetic Time Reversal

23. Fault location in transmission lines using EMTR 22 The time-reversal focusing procedure: a. Transient waveforms generated by a source propagate through the medium and are recorded by sensors. b. The recorded signals are reversed in time and re-emitted back to the medium. In view of the reversibility in time of the wave equation, travelling waves are refocused into the source point N. Mora, F. Rachidi, M. Rubinstein, "Application of the Time Reversal of Electromagnetic Fields to Locate Lightning Discharges", Journal of Atmospheric Research, Vol. 117, pp. 78-85, 2012.

24. Fault location in transmission lines using EMTR 23 The time-reversal focusing procedure:

25. Fault location in transmission lines using EMTR 24 Electromagnetic time reversal (EMTR) in transmission lines Wave equation is time invariant

26. Fault location in transmission lines using EMTR 25 Fault location algorithm based on EMTR

27. Fault location in transmission lines using EMTR 26 Application example HV transmission lines (simulation) Line ParameterPhase aPhase bPhase c DC resistance0.018 /km Outside diameter5.626 cm Horizontal distance-7.4 m 0 m7.4 m Vertical height at tower28.5 m 29.5 m28.5 m Vertical height at midspan 28.5 m29.5 m28.5 m

28. Fault location in transmission lines using EMTR 27 Application example (reduced-scale experimental setup)

29. Fault location in transmission lines using EMTR 28 A.Inhomogeneous network composed of mixed overhead-coaxial cable lines. 3ph fault, Xf= 7km, Rf= 0 3ph fault, Xf=5 km, Rf= 100

30. Fault location in transmission lines using EMTR 29 B. Radial distribution network: IEEE 34-bus test distribution feeder 3ph, Xf= 808, Rf=0 3ph, Xf= 812, Rf=100

31. Fault location in transmission lines using EMTR 30 B. Radial distribution network: IEEE 34-bus test distribution feeder 1ph, Xf= 810, Rf=0 1ph, Xf= 806, Rf=100

32. Fault location in transmission lines using EMTR 31 C. Series-compensated transmission line Three-phase-to-ground fault Double-phase-to-ground faultSingle-phase-to-ground fault

33. Thanks for your attention Questions?