Dommel_PPT

7/30/2019 Dommel_PPT

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The University of British Columbia (UBC)Department of Electrical & Computer Engineering

Past, Present and the Future of

Electric Power Systems

from my Perspective

Hermann W. [email protected]

Zagreb, April 20, 2007

The University of British Columbia

Please ask questions as we go along.


2/18


I studied Power Engineering at TechnicalUniversity of Munich in Germany.

My Diplomarbeit was on power flowsolution for a simplified network of theBavarian Transmission System (1959).

I used thisFridenelectro-mechanicalcalculator:


For Ph. D. thesis in Munich (1962), I workedon short circuit, normal and optimal powerflow solutions for digital computers.

Digital (mainframe) computers were not thatcommon at thattime.

Here is my firstcomputer PERM

(in DeutschesMuseum inMunich now).

Built in 1956 at the University.

Worked with 2500 radio tubes.


3/18


First programs that I wrote were inmachine code.

y = ax + x2 looked like this:100 read into register (x)

101 store into location 107

102 read into register (a)

103 add value from 107 to register (a + x)

104 multiply with value from 107in register (a + x) x

105 print the value in register

106 stop


Fortunately, programming language ALGOLbecame available for most of my Ph. D. work.

To solve 2 linear equations,I could simply write:

BEGIN REAL A11, A12, A21, A22, X1, X2, Y1, Y2, D;

READ (A11, A12, A21, A22, Y1, Y2);

D: = A11*A22-A12*A21;

IF ABS(D)


4/18


Input device wasa paper tape onteletype machine.

Output devicewas the teletypeprinter.

ALGOL codeALGOL code

Machine codeMachine code


From 1962 to 1966, I worked as a Postdoctoral Fellow atTechnical University Munich on an electromagnetictransients program, that became EMTP later on.

I also worked with a Transient Network Analyzer.


5/18


From 1966 to 1973, I worked in industry for the

utility company Bonneville Power Administrationin Portland, Oregon, U.S.A. on:

further development of EMTP,

optimal and normal power flow,

stability with implicit integration.

Programming language was FORTRAN.

As a U.S.A. Government Agency, what we did wasavailable for free under the Freedom of Information

Act. This helped me in getting my work known.


My experience from Ph.D. work on power flowsolutions was useful.

From nodal equations

,

I derived Newtonsmethod for thecurrent-equationform, withrectangularcoordinates Re{Vk}and Im{Vk} asvariables.

0

0

1

1

=

=

=

=

n

m

*

k

kkmkm

n

m

*

k

kkmkm

V

jQPVYIm

V

jQPVYRe

[ ][ ] [ ]*

k

kkk

V

jQPIwithIVY

==


6/18


Jacobian matrix for solving equations iteratively

is almost the real form of the [Y]-matrix:[ ] [ ][ ] [ ]

[ ] [ ] [ ]BjGYwhereGB

BG+=

From thesis 1962:From thesis 1962:


The entries into the diagonal elements ruin thepossibility to write it as complex equations withcomplex variables.

Reason: these terms do not fulfill the Cauchy-Riemann conditions that definite analytic functions.

For , the Cauchy-Riemannconditions say that

which are not true in the four diagonals because ofthe terms coming from the complex conjugatevoltage in

)jyx(fjvu +=+

x

v

y

uand

y

v

x

u

=

=

*

k

kkk

V

jQPI

=


7/18


Bonneville Power Administration used the power-equation form, with polar coordinates |Vk| and kas variables, where :

In this form, it is somewhat easier to handle nodeswhere Pk and|Vk| is specified in this form.

0

0

1

1

=

=

=

=

k

n

m

mkm

*

k

k

n

m

mkm

*

k

QVYVIm

PVYVRe

kjkk eVV

=


Current-equation form with rectangular coordinateshas recently been used for three-phase power flowsolutions in distribution networks:

1. Paulo A.N. Garcia, Jose Luiz R. Pereira, SandovalCarneiro, Vander M. da Costa, Nelson Martins,Three-phase power flow calculations using thecurrent injection method, IEEE Trans. PowerSystems, Vol. 15, pp. 508-514, May 2000.

2. Paulo A.N. Garcia, J.L.R. Pereira, SandovalCarneiro, Marcio P. Vinagre, Flvio V. Gomes,

Improvements in the representation of PV buseson three-phase distribution power flow, IEEETrans. Power Delivery, Vol. 19, pp. 894-896, April2004.


8/18


In 1973, I joined the University of British

Columbia (UBC) in Vancouver, Canada,where I am Emeritus now.

Most work with my graduate students at UBC hasbeen on power system transients (EMTP-typeprograms).

Some work with graduate students at UBC, thatfound its way into many versions:

Laurent Dub: Transient analysis of control systems (TACS).

Jos Marti: Frequency-dependent line models.

Vladimir Brandwajn: Synchronous machine model.

K. C. Lee: Untransposed line model. Luis Marti: Cable models.

Many other contributions.


(from A. R. Bergen & V. Vittal,

Power System Analysis,2nd Ed., Prentice Hall, 2000).

Western Electricity

Coordinating

Council.

British Columbiais part of thisinterconnectedsystem.


9/18


Long

distancesfromgenerationto loads(1200 km).

More than90 % ishydro-electricpowerplants.

AlaskaAlaska

BritishBritish

ColumbiaColumbia


10/18


Three parts:

generation,

transmission,

distribution.

In the past, all three were verticallyintegrated.

With de-regulation coming now, there isseparation to allow competition.

B.C. Hydro & Power Authority split offtransmission part to B.C. TransmissionCorporation.


Before de-regulation, there was fairly free exchangeof data among utility companies.

This made planning of generation and transmissioneasy on an integrated basis.

With de-regulation, there is only limited sharing ofdata.

There is more uncertainty who will supply power.

Government wants local distributed generationresources, including micro-turbines, fuel cells, solar,

and wind generators. Integrating these small independent power

producers causes new engineering problems.

Distribution systems may become meshed.


11/18


12/18


Options in undergraduate program:

Software Engineering.

Biomedical Engineering (starting Sept. 2006).

Electric Power Systems (starting Sept. 2007).


We have a website that describes what wedo: www.ece.ubc.ca/power/

Professors:

Jos R. Mart

William G. Dunford

Juri Jatskevitch

Luis Linares

Retired professors (professor emeritus): Hermann Dommel

K. D. Srivastava

L. M. Wedepohl


13/18


We also ask experts from industry to help inteaching:

Until 2006: Prabha Kundur, AdjunctProfessor (moved to Toronto)

Charles Henville, consultant (was with B. C.Hydro working in protection)

Mukesh Nagpal, B. C. Hydro (protection)


Current Research Projects

Real-Time Power Systems Simulator(OVNI)

Network Partitioning Techniques for LargeSystem Solutions (MATE)

PC-Cluster Architectures

Multi-Rate and Hybrid Solutions


14/18


Signal Processing Techniques for IntelligentDiagnostic Systems

A current project involves the signaturecharacterization of power transformers fromtheir high-frequency response. This signature isthen used for the detection of incipient faultsand aging defects while the transformer is inservice.

Frequency Dependent Transmission LineModelling

High-Frequency Transformer Modelling


Coordination and Control of Small-SizeDistributed Generation Systems

An important area of current interest in hisgroup is the simulation of distributed energysystems. Together with other members of thePower Systems Group and the PowerElectronics Group, they are studying thecoordinated operation and control of localdistributed generation resources (LDR's),including microturbines, fuel cells, solar, and

wind generators, sharing resources with eachother and with the existing power grid.


15/18



Power electronics applied to photovoltaicapplications and alternative energy systems. Pumpand traction drives, high power converters. Micro-controllers and DSP controllers. Distributed EnergySystems. Low power converters. Some examples:

CANADIAN CABLE LABS - A Battery ChargeEqualizing Circuit.

BC HYDRO - A Photovoltaic Powered WaterCirculator.

Canadian Space Agency - Battery Management

System. Design and construction of a 250 kVA IGBT based

inverter system.



Fast and computationally efficient models ofelectrical machines for EMTP-Type programs. Theso-called voltage-behind-reactance model(developed at Purdue University) is used thatachieves a simultaneous EMTP solution of themachine equations with the external network. Athree-phase synchronous machine model requiresonly 250 flops per time step, which executes underfour microseconds on an average PC.


16/18


Continuous and computationally efficient dynamic

average-value models of power and power-electronic systems/components containingconverters, inverters, rectifiers, and rotatingelectrical machines. The goal is to automaticallygenerate models wherein the effects of fastswitching is neglected or "averaged" with respectto a prototypical switching interval and therespective state variables are constant in thesteady-state. Method is very accurate in both thetime- and frequency-domains, and fast.

Chairs IEEE PES Task Force on Dynamic Average

Modeling.


Modeling and control of distributed energyresources. Proposed an innovative supervisorycontrol scheme for wind farm applications thatallows to use distributed wind turbines to regulatethe voltage at required remote location(s), whiletaking into consideration dynamics and the real-time power limits of each individual wind turbine.


17/18



Computer simulation of engineering systems. Real-time simulation of engineering systems. Modellingof electric machines in real time. Real-timeoperating systems for embedded applications.


H. W. Dommel

Some work on EMTP issues.

Has been teaching one course ComputerApplications in Power, to help out with staffshortage.

K. D. Srivastava

Helps with a new university in Trinidad-Tobago.

L. M. Wedepohl

Helps with new campus in Kelowna.

Plans to write a book about solution of transientswith frequency-domain methods.


18/18


Technical adviser to EMTP DevelopmentCoordination Group.

Using dynamic phasors for slow transients.

Consulting work with a former Ph. D. student inArgentina:

Switching of shunt reactors.

Useful input from experiments done here:Ivo Uglei, Sandra Hutter, Miroslav Krepela,Boidar Filipovi-Gri, and Franc Jakl,Transients due to switching of 400 kV shuntreactor, International Power Systems TransientsConference IPST 2001, Rio de Janeiro, Brazil, June24-28, 2001.


Thank you for your invitation!

Any questions?

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