An Overview of Simulation Tools for Electromagnetic Transients in Power Systems J. Mahseredjian, V. Dinavahi, J. A. Martinez IEEE PES General Meeting, 2007 1 Overview and Summary • EMT-type (EMTP-type) – Electromagnetic transients (native) – Electromechanical transients (extension to) • Currently available tools: most widely recognized and available, industrial grade • Off-line Simulation tools • Real-time Simulation tools • Application fields IEEE PES General Meeting, 2007 2 Applications • • • • • • • • • • • • • • • • • Multiphase, Steady-state, Load-flow Lightning, switching and temporary overvoltages Insulation coordination Ferroresonance, saturation and surge arrester influences Harmonic propagation, power quality Interaction between compensation and control components Wind generation: mean-value models and detailed models Distributed generation, microgrids Precise analysis of short-circuit currents Detailed behavior of synchronous machines and related controls, autoexcitation Subsynchronous resonance Power oscillations Protection systems Multiterminal HVDC systems, power electronics applications FACTS and Custom Power devices Advanced Transient Stability analysis (more and more) Electromagnetic Compatibility IEEE PES General Meeting, 2007 3 Range of Transient phenomenon 7 Lightning Voltage (p.u.) 6 5 Switching 4 3 2 Temporary 1 -6 10 10 10 kHz to 3 MHz -4 10 -2 10 0 10 2 10 4 t (s) 60 Hz to 20 kHz 0.1 to 1 kHz IEEE PES General Meeting, 2007 4 ZnO1 Out 400 km, 500 kV DYg 1 2 SM BRk SM + >e + W2 V500m 500/230/50 + ?m RA BRL 1 + V500k + AVR&Gov (pu) BRm 13.8/500 1 IN 2 400km + YgYgD ZnO2 3 + 13.8kV 800MVA AVR_Gov + ZnO 700 MW + ZnO >e Example: Temporary overvoltages + 20nF 1uF 800 600 V500ma (kV) 400 200 0 -200 -400 -600 -800 0 100 200 300 400 500 t 600 700 800 900 1000 (ms) IEEE PES General Meeting, 2007 5 Example: Line switching transients 600 phase a phase b 400 L4m (kV) 200 0 -200 -400 phase c -600 0 5 10 15 20 25 30 t (ms) IEEE PES General Meeting, 2007 6 Electromechanical transients with EMTP-type programs • Lower frequency, longer time-scale • More precise – Accounts for nonlinearities in the network – More sophisticated models: loads, network • Requires specific models and methods – Load-flow solution and initialization – Frequency and voltage dependent load models IEEE PES General Meeting, 2007 7 Network separation studies with arrester models 5 8 PLOT x 10 Station_B/V1a@vn@1 6 4 2 y 0 -2 -4 -6 -8 -10 0 0.5 1 1.5 2 time (s) 2.5 IEEE PES General Meeting, 2007 3 3.5 4 8 0.04 0.035 Network Islanding with detailed load models 0.03 Slip_ASM2 Slip_ASM3 Slip_ASM4 Slip_ASM5 Slip_ASM6 0.025 0.02 0.015 0.01 0.005 10 12 14 16 Vnet VM + ?v 13.8kV 500MVA + 13.8/122 SM2 1 + 120/26.4 1uF ASM1 1 C3 YgD_1 Q P YgYg_np2 2 1 ?i 120kV /_17 3 9/9.15/0 9/9.15/0 1E15/1E15/0 0.2uF Equivalent 120 kV Network + S 0.1 1Ohm 25.5/6.6 1 + 40uF 25.5/12 C4 YgYg_np1 + 6.6kV 11000hp ? SW_ASM1 1/1E15/0 ?m 2 ASM 0.2uF 2 Tm Network Q + + scope scope T S AVR&Gov (pu) P + Speed IN Q_ASM1 P_ASM1 ASM1_control SW_Network ?i + SM 1 Starting motor at 1 s ?m Q_net SW_Fault + Out AVR_Gov_SM2 P_net -1/9.15/0 DYg_SM2 1 2 + 8 time (s) + 6 + 4 scope 2 Fault & System Islanding at 9 s scope 0 0 380uF C7 ?m P SM_load Q Load1 420 MW Load f(u) 1 SM_load_control Omega_1 6.6kV 11000hp Pm ASM2 ASM S 6.6kV 11000hp ?m ASM3 ASM S 6.6kV 11000hp ?m ASM4 ASM S 6.6kV 11000hp ?m ASM5 ASM ASM6 6.6kV 11000hp ?m ?m ASM S 240uF S + 12kV 40MVA SM Induction motors in steady-state 32 MW Synchronous Motor Load IEEE PES General Meeting, 2007 9 Off-Line Simulation tools • ATP, EMTDC, EMTP-RV, SPICE (…), Saber, Simulink/Matlab • Standard computer environments • Ultimate precisions, computational luxury • Optimized speed • Graphical User interface (modern tools) • Codes with connectivity to external tools: DLL, Active-X • User-defined modeling languages • Connectivity to hardware (open-loop) – Replay dumped waveforms – Insert controller codes through DLL or Libs IEEE PES General Meeting, 2007 10 Families of specialized tools • Power systems (EMTP-Type) – Distinctive specific models – Nodal analysis or modified-augmented-nodal analysis formulation, sparse matrix based solvers – Control systems: block-diagrams – Newton methods for nonlinearities • Electronic circuits (SPICE-Type) – – – – – Distinctive specific models Detailed electronic switch models Nodal analysis or modified-nodal-analysis, sparse matrix solvers Control systems: circuits or block-diagrams Newton methods for nonlinearities • Not necessary monotonically increasing • Multiple solution search methods • Combined package? IEEE PES General Meeting, 2007 11 Specialized tools: advantages • Computational speed • Large scale – The computational speed is improving – Large scale network simulation for multipurpose analysis • Combination of electromagnetic and electromechanical time frames • EMTP-type software GUIs and engines can handle extremely large networks within acceptable computational time. • SPICE-type packages can simulate millions of transistors • • • • Modeling sophistication Specialized research background Wideband Usually more user-friendly IEEE PES General Meeting, 2007 12 Toolboxes in specialized tools • • • • • Induced lightning: LIOV Direct lightning: Lightning workstation Parametric study tools Mapping of data from PSS/E Electromagnetic coupling – CRINOLINE • Coupling between lines, cables, gas pipelines fences, telecommunication IEEE PES General Meeting, 2007 13 General purpose modeling environments • • Matlab/Simulink Specialized Toolboxes – – – – • • • • • • • • Control systems, Simulink Design tools SimPowerSystems (state-space based) PLECS Advantageous user configurability and user-defined modeling Combination of design tools Mixed-simulation options by customization or toolboxes Non-specialized Smaller case applications. Significant performance issues. Some combinations must approximate solutions to accommodate Not a direct access to internal mathematics Not for every user IEEE PES General Meeting, 2007 14 Combined tools • Mixed technology simulations • Mixed methods – Phasor solutions and time-domain solutions – Nodal analysis and state-space – Frequency-domain and Time-domain • For initialization algorithms – Symbolic-numeric computations • Specialized tools linked with general purpose modeling environments – – – – The best of both worlds No standards, can become cumbersome Not simple to maintain Simultaneous solutions remain problematic IEEE PES General Meeting, 2007 15 Mixed-Technology simulations • Simulations for different engineering domains – Electrical, electronic, hydraulic, mechanical, thermal • Applications – Automotive industry • Engine model, controls, electronics – Wind generation • Detailed computation of Torque (wind effects, aerodynamic formulas), multimass machine model, power system, controls • Important field IEEE PES General Meeting, 2007 16 Example: Mixed simulation Wind Turbine DFIG Wind + 2 + 1 ASM + Converter Controller teta teta wind_speed IEEE PES General Meeting, 2007 17 Example: Mixed Simulation + + FLUX 3D V source Extra data : • Internal forces • Internal fluxes Ikm + DLL interface I source Vkm EMTP Network Simulation Data : • Time • Simulation flag EMTP-RV IEEE PES General Meeting, 2007 18 Representation of the magnetic circuit and coils in FLUX3D IEEE PES General Meeting, 2007 19 Real-Time Simulation Tools Advantage: Unlike off-line simulation tools, real-time tools can be used to test external hardware (e.g., control, relays) by interfacing. Real-time simulation tools can based on either analog or digital components. Three main kinds of real-time simulation tools: Transient Network Analyzers (TNAs). Real-Time Digital Simuators. Real-Time Playback Simulators. IEEE PES General Meeting, 2007 20 Transient Network Analyzers (TNAs) TNA is an assemblage of scaled down models of physical equipment with a topology similar to the physical power system Based on analog components. Advantage: Real-time capability and comprehensive hardware-in-the-loop testing of control and protection equipment. Disadvantages: Need significant resources to build and maintain. Excessive time to prepare and change test setups. Lack scalability for detailed system representaion. Inability to accurately model system components e.g., distributed parameter transmission lines. IEEE PES General Meeting, 2007 21 Real-Time Digital Simulators Best alternative to a analog TNA. Using parallel and distributed digital processing technology, system differential equations are solved with a discrete timestep. Several commercially available real-time digital simulators such as RTDS, RT-LAB, HYPERSIM Applications: Closed-loop testing of digital controllers for power electronic based FACTS and HVDC systems. Closed-loop testing of protective relays. Electromagnetic transient simulations of large-scale systems. Real-time harmonic modeling and simulation for Power Quality (PQ) evaluation. IEEE PES General Meeting, 2007 22 Real-Time Digital Simulators (contd.) HS1 HS2 OK1 OK2 PS 1 2 3 4 5 6 7 8 9101112 COLACTSTA- 1X 6X 24 12X 7X 18 19X STATUS green = enabled, link OK flashing green=disabled,link OK off = link fail TCVR1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 1920 21 22 23 24 13 14 15 16 17 18 1920 21 22 23 24 Module Packet Status Packet Status 25X 10BaseTX/100Base TX 26X UNIT 1 2 3 4 24 26 Packet 5 6 24 26 Status 7 8 HiNet WS 4400 SIEMENS IEEE PES General Meeting, 2007 CONSOLE 13X PC-Cluster based real-time digital simulator Fully flexible and scalable. Fast FPGA based analog and digital I/O interfaces. Two groups of off-the-shelf computers: Targets and Hosts. Target computers contain dual 3GHz Intel Xeon processors with shared memory. Communication links: Infiniband (10Gbps), Shared Memory (2.7Gbps), Gigabit Ethernet (1Gbps). Model development software: MATLAB/SIMULINK, C, C++, … Variety of synchronization options 23 Real-Time Playback Simulators Transient data is first generated by an off-line EMTP program. The stored data is played back synchronized in realtime to the device under test. Disadvantage: A playback simulator can test device only under open-loop conditions since it is not possible to predict the device response a priori. Advantages: Can utilize the full capabilities of off-line EMTP-type programs. Since transient data is collected off-line size or complexity of model not an issue. Multiple test runs can be scheduled enabling automated evaluation of test equipment. Can reproduce complex waveforms without the constraint of accuracy or bandwidth. IEEE PES General Meeting, 2007 24 Conclusions • Off-line simulation tools – Wideband, increased precision – Can solve extremely large and complex problems • Real-time simulation tools – Advantages for testing physical components – Advantages for performing multiple simulations • Trends – – – – – Larger and larger network simulations Mixed-Technology simulations Combination of solution methods Improved computational speed on standard computers Need for modeling standardization IEEE PES General Meeting, 2007 25
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