an overview of simulation tools for electromagnetic...

IEEE PES General Meeting, 2007 1

An Overview of Simulation Tools for Electromagnetic Transients in

Power Systems

J. Mahseredjian, V. Dinavahi, J. A. Martinez


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


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, auto-

excitation• 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


10-6

10-4

10-2

100

102

104

1

2

3

4

5

6

7

t (s)

Vol

tage

(p.

u.)

Lightning

Switching

Temporary

10 kHz to 3 MHz60 Hz to 20 kHz 0.1 to 1 kHz

Range of Transient phenomenon


400 km, 500 kV700 MW

+

1uF

+

1

SM

13.8kV800MVA

?m

SM

AVR&Gov(pu)

Out

IN

AVR_Gov2

3

1

YgYgD

500/230/50 +

+Zn

O

ZnO2

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O

ZnO1

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+

20nF

+BRk

RA

+BRm +

BRL

+400km1 2

13.8/500

DYg

W2V500mV500k

0 100 200 300 400 500 600 700 800 900 1000-800

-600

-400

-200

0

200

400

600

800

V50

0ma

(kV

)

t (ms)

Example: Temporary overvoltages


0 5 10 15 20 25 30

-600

-400

-200

0

200

400

600

t (ms)

L4m

(kV

)

phase a

phase b

phase c

Example: Line switching transients


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


Network separation studies with arrester models

0 0.5 1 1.5 2 2.5 3 3.5 4-10

-8

-6

-4

-2

0

2

4

6

8x 105

time (s)

y

PLOT

Station_B/V1a@vn@1


Equivalent 120 kV Network

Fault & System Islandingat 9 s

Starting motor at 1 s

420 MW Load

32 MW Synchronous Motor Load

Induction motors in steady-state

1 2DYg_SM2

13.8/122

+

0.2uF

+

3

+

1uF

+1

+

120kV /_17

Network+

12

YgD_1

120/26.4

12YgYg_np1

25.5/12

SMSM_load

?m12kV40MVA

0.11Ohm

12YgYg_np2

? 25.5/6.6

+

1/1E15/0

?i

SW_ASM1

+

40uF

C4

PQ

scop

e

Q_ASM1

scop

e

P_ASM1

+

240uF

P Q+

-1/9.15/0

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+

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+S

W_F

ault

9/9.15/09/9.15/01E15/1E15/0

+

1

scop

e

P_net

scop

e

Q_net

P Q Load1

+

C7 380uF

ASM

S

6.6kV11000hp

?m

AS

M2

ASM

S

6.6kV11000hp

?m

AS

M3

ASM

S

6.6kV11000hp

?m

AS

M4

ASM S

6.6kV11000hp

?m

ASM1

SM

SM2

?m

13.8kV500MVA

AVR&Gov(pu)

Out

IN

AVR_Gov_SM2

Speed Tm

S T

ASM1_control

Pm

Om

ega_

1f(u) 1SM_load_control

VM+Vnet

?v

ASM

S

6.6kV11000hp

?m

AS

M5

ASM

S

6.6kV11000hp

?m

AS

M6

0 2 4 6 8 10 12 14 160

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

time (s)

Slip_ASM2Slip_ASM3Slip_ASM4Slip_ASM5Slip_ASM6

Network Islanding with detailed load

models


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


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?


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


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


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


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


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


Wind Turbine

Wind

teta

wind_speedConverterController te

ta

ASM

12

+

+

+

DFIG

Example: Mixed simulation


Example: Mixed Simulation

Vkm

FLUX 3D

EMTP-RV

Extra data : • Internal forces • Internal fluxes

Simulation Data : • Time • Simulation flag

Ikm

DLL

V source

I source

+

EMTP Network

+

+

interface


Representation of the magnetic circuit and coils in FLUX3D


Real-Time Simulation ToolsAdvantage: Unlike off-line simulation tools, real-time tools

can be used to test external hardware (e.g., control, relays) byinterfacing.

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.


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.


Real-Time Digital SimulatorsBest alternative to a analog TNA.Using parallel and distributed digital processing technology,

system differential equations are solved with a discrete time-step.

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.


Real-Time Digital Simulators (contd.)

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

SIEM

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HiN

et WS

4400

1X6X

13X18

7X12X

19X24

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Sgreen = enabled, link O

Kflashing green=disabled,link O

Koff = link fail

TC

VR

Module

Packet

Status

Packet

Status

1314

1516

181920

2122

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Status

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1 2 3 4 5 6 7 8 9101112HS1 HS2 OK1 OK2 PS

CONSOLE


Real-Time Playback SimulatorsTransient data is first generated by an off-line EMTP

program. The stored data is played back synchronized in real-time 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.


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

an overview of simulation tools for electromagnetic...

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