© K.U.Leuven – ESAT/Electa

MatDyn, A New Matlab Based Toolbox

for Power System Dynamic Simulation

Stijn Cole, Ronnie Belmans

stijn.cole@gmail.com

Presented by Dirk Van Hertem

© K.U.Leuven – ESAT/Electa

• Introduction

• Why MatDyn?

• Implementation

• Validation

• Applications

• Conclusions

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© K.U.Leuven – ESAT/Electa

Introduction

o Commercial Software

• Fully-featured

• Steep learning curve

• Computationally efficient

• Implementation details

and models hidden from

users

• Not always well suited

for education and

research

o Academic Software

• Often open-source

• Can be adapted

• High level programming

language (Matlab,…)

• Easier to use

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© K.U.Leuven – ESAT/Electa

Why MatDyn?

o MATPOWER

• Only PF and OPF

• Very easy to use

• Easy scripting

• Philosophy:

“It is intended as a simulation tool

for researchers and educators that

is easy to use and modify.

MATPOWER is designed to give

the best performance possible

while keeping the code simple to

understand and modify.”

o PSAT

• Fully-featured: stability,

power flow, OPF,

bifurcation analysis,

GUI,…

• Wide range of features

makes the code involved

• Hard to modify

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© K.U.Leuven – ESAT/Electa

Why MatDyn?

o MATPOWER • Only PF and OPF

• Very easy to use

• Easy scripting

• Philosophy:

“It is intended as a simulation tool

for researchers and educators that

is easy to use and modify.

MATPOWER is designed to give

the best performance possible

while keeping the code simple to

understand and modify.”

o PSAT

• Fully-featured: stability,

power flow, OPF,

bifurcation analysis,

GUI,…

• Wide range of features

makes the code involved

• Hard to modify

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MatDyn: extending use of MATPOWER to dynamic analysis, while strictly adhering to its philosophy

© K.U.Leuven – ESAT/Electa

MatDyn Goal

o Seamless integration in MATPOWER

• Uses same case files for PF data

• No MATPOWER files changed

• Uses equivalent scripts and syntax:

• …

o Synergy between OSS projects in line with

objectives of IEEE taskforce

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© K.U.Leuven – ESAT/Electa

Example

o MATPOWER

> options = mpoption;

> runpf(‘case9’,options);

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o MatDyn

> options = mdoption;

> rundyn(‘case9’,’case9dyn’,’event’,options);

© K.U.Leuven – ESAT/Electa

Implementation

o Challenge: to keep the

code simple

o Problem: dynamic

simulation inherently

more complicated than

PF/OPF

o Solution: design

criteria and choices on

implementation

o Trade-off between code simplicity and accuracy or features leading to choices on

• Simultaneous vs partitioned scheme

• How to solve algebraic equations

• Disallowing generator transient saliency

• Disallowing non other than constant impedance loads

• …

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© K.U.Leuven – ESAT/Electa

MatDyn Flow Chart

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System to solve Call MATPOWER

X = dynamic state variables Y = algebraic state variables

F = differential equations G = algebraic equations

P = parameters

© K.U.Leuven – ESAT/Electa

Trade-off:

Simultaneous vs Partitioned

o Simultaneous

• Solve system

simultaneously

• constructing whole

Jacobian before solving

makes the code intricate

o Partitioned

• Solve G for Y and then

• Solve F for X

• Sequential integration of

equipment: generators,

governors,…

• Code easy to read

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© K.U.Leuven – ESAT/Electa

Trade-off:

Speed vs Detail o Two conditions are

imposed

• Transient saliency not allowed

• Only constant admittance loads allowed

o Consequence: algebraic equations are linear, can be solved very efficiently in MATLAB by LU factorization of Ybus

o Remark

• Would not be acceptable

for commercial program

• For software geared

towards education and

research, such an

approach is deemed

acceptable

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© K.U.Leuven – ESAT/Electa

Validation: Anderson & Fouad

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MatDyn

Anderson & Fouad

© K.U.Leuven – ESAT/Electa

Validation: Stagg & El-Abiad

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© K.U.Leuven – ESAT/Electa

Solvers

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© K.U.Leuven – ESAT/Electa

Applications

Education

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o Used in power system course

o Example: implement fossil-fueled single reheat

tandem-compound turbine with governor

© K.U.Leuven – ESAT/Electa

Applications

Research

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o Research on

multi-terminal

VSC HVDC

o Example:

dynamic

simulation of line

outage in six-

terminal VSC

HVDC system

© K.U.Leuven – ESAT/Electa

MatDyn: Status

o http://www.esat.kuleuven.be/electa/teaching/matdyn/

o Used in Belgium, China, India, UK, Brazil, …

o Python port underway (Pylon, by Richard Lincoln)

o Support: minimal (author not at university anymore)

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© K.U.Leuven – ESAT/Electa

Developing MatDyn:

Lessons learned

o There is a looooong way from having working

software that you can use to releasing software

that everyone can use

o Validation is necessary: all software has bugs,

including/especially software that you write

yourself

o Writing power system software is a sure way to get

a deep understanding of power systems

o More people are interested in your software than

you think

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© K.U.Leuven – ESAT/Electa

Conclusion

o Easy-to-use power

system dynamic

simulation tool

o Synergy with

MATPOWER

o Applications in

research and

education

o We hope MatDyn can

be of use to the power

system community

o The software including

source code and full

documentation are

available for free

download

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http://www.esat.kuleuven.be/electa/teaching/matdyn/ Comments welcome: stijn.cole@gmail.com