Post on 15-Jan-2016
Third US-Africa Research and
Education Collaboration WorkshopAbuja, Nigeria, December 13-15, 2004
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Third NSF Workshop on US-Africa Research and Education CollaborationAbuja, Nigeria, December 13-15, 2004
TECHNOLOGY &
ENVIRONMENT
ENERGY &
EDUCATION
TECHNOLOGY &
ENVIRONMENT
ENERGY &
EDUCATION
Professors John Ngundam and Emmanuel Tanyi of Ecole Polytechnique, University of Yaounde I
Third US-Africa Research and
Education Collaboration WorkshopAbuja, Nigeria, December 13-15, 2004
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STRUCTURE OF THE AUTOMATION AND CONTROL LABORATORY (ACL)
Laboratory Director: Professor John M. Ngundam Power Systems, Renewable Energy and Environmental Simulation Group Leader: John Ngundam (Professor)
COMPUTER AND PROCESS CONTROL Group Leader: Emmanuel B. Tanyi (Associate Professor)
Telecommunications and Informatics Group Leader: Ndeh Ning, PhD
Center for Health Technology F. Sop Boyom, PhD
John M. Ngundam
Third US-Africa Research and
Education Collaboration WorkshopAbuja, Nigeria, December 13-15, 2004
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RESEARCH PROJECTS IN PROGRESS
Power Systems, Renewable Energy & Environmental Simulation
With 294 TWh of industrial scale hydro electricity resources and an enormous potential for small scale hydro electricity production for rural and remote area electrification, Cameroon is still a country with very low access rates to electricity. At the present time, only 7639 GWh a year of this potential is being produced to serve a population of 20 million not to mention export possibilities. Present research effort is directed towards the following:Generation and Network Expansion PlanningElectricity for Rural Electrification from Renewable Energy SourcesWater Resource Modelling and ManagementLoad ForecastingElectricity Markets (very recent addition)Analysis of Transients in Networks
Several long-, medium- and short-term generation planning software packages are being tested or nearing final development. Systems dynamics methods are being introduced in modelling water flows for use in developing large hydro plants and low voltage networks based on renewable energy sources.
John M. Ngundam
Third US-Africa Research and
Education Collaboration WorkshopAbuja, Nigeria, December 13-15, 2004
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RESEARCH PROJECTS IN PROGRESS CONTINUED
COMPUTER AND PROCESS CONTROL
Research into the electric system expansion and development of low voltage transformer free rural networks based on renewable energy have led to a need to develop system control technologies appropriate for controlling this and other systems. On going projects include:
Multivariate Control of the Southern network of the Cameroon Power SystemState SPACE Control of the Songloulou Power Generation StationMicroprocessor based Control of the Medium and Low Voltage Transmission Sytems of the Southern NetworkAnalysis of Pertubations in the Southern Network of the Cameroonian System
John M. Ngundam
Third US-Africa Research and
Education Collaboration WorkshopAbuja, Nigeria, December 13-15, 2004
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RESEARCH PROJECTS IN PROGRESS CONTINUED
Telecommunications and Informatics
Design and analysis of optimum and suboptimum receivers for signal detection in non-Gaussian noise
Application of self-critical statistical methods to signal detection. Information and communication technologies and society: governance,Sovereignty, digital divide
Computer and communication networks
Power line communication
John M. Ngundam
Third US-Africa Research and
Education Collaboration WorkshopAbuja, Nigeria, December 13-15, 2004
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REPORTS ON SELECTED PROJECTS
DIGITAL INFORMATION TRANSMISSION ON
ELECTRIC POWERLINES
COMPUTER AND PROCESS CONTROL
John M. Ngundam
Third US-Africa Research and
Education Collaboration WorkshopAbuja, Nigeria, December 13-15, 2004
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DATA TRANSMISSION OVER POWER LINES BY MODIFICATION OF THE POWER WAVEFORM
INTRODUCTION VOLTAGE SUPPRESSION AFTER ZERO-
CROSSING (VSZC)TECHNOLOGYMATHEMATICAL MODEL OF THE TECHNOLOGYERROR PROBABILITY CONSIDERATIONSLABORATORY RESULTSPERSPECTIVES
J.M. Ngundam
Third US-Africa Research and
Education Collaboration WorkshopAbuja, Nigeria, December 13-15, 2004
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DIGITAL INFORMATION TRANSMISSION ON ELECTRIC POWER LINES
The power waveform is modified after a defined duration , after the zero-crossing.
Technology demonstrated for transmission of signals for controlling (i.e. turning of and on) of devices connected to low voltage (220 V ) electric network and for remote meter reading.
In the Voltage suppression After zero-crossing (VSZC) technology, a bit “1” is assumed transmitted when suppression occurs and bit “0” when there is no suppression. Suppression time , is a critical parameter which determines the spectral distribution of the power signal and determines the error probability performance of the system.
J.M. Ngundam
Third US-Africa Research and
Education Collaboration WorkshopAbuja, Nigeria, December 13-15, 2004
9
VOLTAGE SUPPRESSION AFTER ZERO-CROSSING
(VSZC) TECHNOLOGY
In VSZC technology, a bit “1” is assumed transmitted when suppression occurs and a bit “0” when there is no suppression.
Suppression time , is a critical parameter which determines the spectral distribution of the power signal and determines the error probability performance of the system
J.M. Ngundam
Third US-Africa Research and
Education Collaboration WorkshopAbuja, Nigeria, December 13-15, 2004
10
MATHEMATICAL MODEL
Modified signal:
f(t) = AoSin (ωot) u(t), (1)
where u(t) is the unit step function defined as: 1 t > 0 (2) u(t) = 0 t < 0Without loss of generality, we analyse a single half period of the signal by adding an identical wave shifted version by T/2 (i.e. f(t) + f(t+T/2) to obtain. f1(t) = f(t) + f(t+T/2)
= Ao Sin(ot)u(t) +AoSin(o(t-T/2)u(t-T/2) (3)
J.M. Ngundam
Third US-Africa Research and
Education Collaboration WorkshopAbuja, Nigeria, December 13-15, 2004
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MATHEMATICAL MODEL CONTINUED
fTrans(t) = Ao Sin(ot)u(t - ) +AoSin(o(t-T/2)u(t-T/2) (4)
where ftrans(t) is the information signal propagated down the line. Modification power signal
results in harmonics which alter the supplied energy is altered. The energy of the modified signal is given by [1], as Em = A2
o (T/4) [ 1 - 2/T + 1/(o T) Sin(2o ) ] (5)
Higher harmonics do not appear at suppression. Optimum value of the suppression time is obtained from : 1 - 2/T + 1/(o T) Sin(2o ) 0 (6)
An iterative solution of (6) gives 1.2 < < 2.55 (7) In this technology, a value of = 1.6 ms was used. This value of also satisfied the utility energy supply because it does not drop to less than 90% of the generated value.
J.M. Ngundam
Third US-Africa Research and
Education Collaboration WorkshopAbuja, Nigeria, December 13-15, 2004
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MODIFIED POWER SIGNAL
J.M. Ngundam
Third US-Africa Research and
Education Collaboration WorkshopAbuja, Nigeria, December 13-15, 2004
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ERROR PROBABILITY CONSIDERATIONS
Transmission error is crucial to the success of the technology. Let the transmission of bits “1” and “0” as:
S1(t) = Ao Sin(ot)u(t - ) +AoSin(o(t-T/2)u(t-T/2) (8)
S0(t) = Ao Sin(ot)u(t) +AoSin(o(t-T/2)u(t-T/2) (9)
The probability performance of the system in terms of the error function Q(*), is given as:
Q() = Q{(Ev/No (2 - Sin(2) / (4 - 2 + Sin()}1/2 (10)
where Ev is the average signal energy and No is obtained from the noise waveform
possesing a Gaussian probability density function and a double –sided power spectral density.
J.M. Ngundam
Third US-Africa Research and
Education Collaboration WorkshopAbuja, Nigeria, December 13-15, 2004
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LABORATORY RESULTS
TESTS CONDUCTED
Remote control of various loads from a single point
Transfer of text between two computers
Adaptation of a standard utility meter for for electronic display and remote reading using the scheme. Inbound and outbound communications are possible provided the targets are within a radius of between 5 and 8 kilometers. If these distances are exceeded, detectability becomes a problem.
J.M. Ngundam
Third US-Africa Research and
Education Collaboration WorkshopAbuja, Nigeria, December 13-15, 2004
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PERSPECTIVES
Present investigations include include:
• Generation and load management for rural and remote stand alone electric systems without transformers. The radius of operation is limited to distances between 5 and 8 kilometres. This is ideal for rural settings in places like Cameroon.
• Remote meter reading and text transmission.
• Interfacing high speed data signals such as the INTERNET,
• Real time transmission of TV signals and voice communications on the power line, through the uses of compression techniques, powerline MODEMS, etc
J.M. Ngundam
Third US-Africa Research and
Education Collaboration WorkshopAbuja, Nigeria, December 13-15, 2004
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MULTIVARIATE CONTROL OF THE SOUTHERN NETWORK OF THE CAMEROONIAN POWER
SYSTEM
– - INTRODUCTION – - DEVELOPMENT OF A MULTIVARIATE
MODEL – - DESIGN OF A MULTIVARIATE CONTROL
SYSTEM– - PERSPECTIVES
Emmanuel B. Tanyi
Third US-Africa Research and
Education Collaboration WorkshopAbuja, Nigeria, December 13-15, 2004
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INTRODUCTION
Capacity of the Power System 805.7 MW Dominance of Hydro Stations : 720 MW (89.4 %) 3 Hydro Stations :• - Edea (264 MW);• - Songloulou (384 MW);• - Lagdo (72 MW)
Structure of the Power SystemNational Power System Organised into 2 Autonomous Networks :
Southern Network (Edea; Songloulou ) Northern Network ( Lagdo )
Emmanuel B. Tanyi
Third US-Africa Research and
Education Collaboration WorkshopAbuja, Nigeria, December 13-15, 2004
18
Fig. 1 : Northern and Southern Networks of the Cameroonian Power Network
YAOUNDE(Oyomabang)
Songloulou
Nkong-Njock
Edéa
Mangombé
Logbaba
Békoko
N'kongsambaBafoussam
Bamenda
Limbé
BassaDeido
Bonabéri
Lagdo
Ngaoundéré
Garoua
Guider
Maroua
LEGEND
Power transmission Station : - 225 kV / 90 kV (Southern Grid) - 110 kV / 90 kV (Northern Grid)
Power transmission Station (90 kV)
Hydro Generating Station
Power transmission line : - 225 kV (Southern Grid) - 110 kV (Northern Grid)
Power transmission line (90 kV)
Emmanuel B. Tanyi
Third US-Africa Research and
Education Collaboration WorkshopAbuja, Nigeria, December 13-15, 2004
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Fig. 2 : Southern Grid of the Cameroonian Power Network
Songloulou
Mangombé
Logbaba
Oy omabang
Békoko
Limbé
N'kongsambaBaf oussam
Bamenda
Bonabéri
DeidoBassa
Mbalmay o
BRGMNgousso
Nkong-NjockEdéa
Koumassi225/90kV
225/90kV
225/90kV
225/90kV
10/225kV
10/90kV
LEGEND
Thermal Generation
Hy dro Generation
HV Loads
Emmanuel B. Tanyi
Third US-Africa Research and
Education Collaboration WorkshopAbuja, Nigeria, December 13-15, 2004
20
PROBLEMS WITH THE SYSTEM
Supply far below demand = Frequent Load shedding
This situation is due to many problems : Obsolescence of equipment (Edea, 1953) Inefficient Control Strategies Industrial Expansion Galloping Population Expansion Decrease in the level of the Sanaga River Silting of the Dams
Situation requires a combination of many solutions.
One solution is the design of more efficient control strategies.
Emmanuel B. Tanyi
Third US-Africa Research and
Education Collaboration WorkshopAbuja, Nigeria, December 13-15, 2004
21
DEVELOPMENT OF A MULTIVARIATE MODEL
• Hydro Generating Stations We have developed a system of 14 equations for each of
the generating stations• Flux Linkages due to Self and Mutual Inductances of the Rotor
and Stator:
r
r
r
s
s
s
3
2
1
3
2
1
rrrsrsrsr
rrrsrsrsr
rrrsrsrsr
srsrsrsss
srsrsrsss
srsrsss
LMMMMM
MLMMMM
MMLMMM
MMMLMM
MMMMLM
MMMML
coscoscos
coscoscos
coscoscos
coscoscos
coscoscos
coscoscos
Notation : 1, 2, 3 refer to phases while the subscripts ‘r’ and ‘s’ refer to the rotor and stator.
r
r
r
s
s
s
i
i
i
i
i
i
3
2
1
3
2
1
Emmanuel B. Tanyi
Third US-Africa Research and
Education Collaboration WorkshopAbuja, Nigeria, December 13-15, 2004
22
Voltage Equations for the Rotor and Stator Circuits :
1111 ssss dt
dIRV 2222 ssss dt
dIRV
1111 rrrr dt
dIRV
2222 rrrr dt
dIRV
3333 rrrr dt
dIRV
Electro-mechanical Equations ( Torque Equations ) :
dt
dJTT R ),,,( rsrsR iifT
Emmanuel B. Tanyi
Third US-Africa Research and
Education Collaboration WorkshopAbuja, Nigeria, December 13-15, 2004
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TRANSMISSION SYSTEM
• The transmission System is modelled as 5 subsystems :-• High Voltage Lines (225 KV) Medium Voltage Lines (90 KV) Low Voltage Lines (220V) Medium Voltage Station Low Voltage Station The Medium Voltage Station Steps down the voltage from 225kV to 90 kV
The Low Voltage Station Steps down the Voltage from 90 KV to 220 V.
Emmanuel B. Tanyi
Third US-Africa Research and
Education Collaboration WorkshopAbuja, Nigeria, December 13-15, 2004
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FIG. 3: COMPONENTS OF THE TRANSMISSION SYSTEM
225 KV Line
Medium Voltage Station
90 KV Line
Low Voltage Station
220 V Line
Emmanuel B. Tanyi
Third US-Africa Research and
Education Collaboration WorkshopAbuja, Nigeria, December 13-15, 2004
25
DESIGN OF A MULTIVARIATE CONTROL SYSTEM
• Configuration of the Control System :• • A Distributed Control System incorporating 4• Multivariate Control Stations :
• - Edea Generation Station•• - Songloulou Generating Station•• - Medium Voltage Transmission Station•• - Low Voltage Transmission Station
Emmanuel B. Tanyi
Third US-Africa Research and
Education Collaboration WorkshopAbuja, Nigeria, December 13-15, 2004
26
FIG. 4 : ARCHITECTURE OF THE DISTRIBUTED CONTROL SYSTEM
Edea Control Station (Hydro
Station)
Sondloulou Control
Station(Hydro Station )
Medium Voltage
Transmission Station
Low Voltage Transmission
Station
Emmanuel B. Tanyi
Third US-Africa Research and
Education Collaboration WorkshopAbuja, Nigeria, December 13-15, 2004
27
CONTROLLER DESIGN STRATEGIES
• 3 Stategies :
Inverse Nyquist Array :
– · Use MATLAB to Calculate Multivariate Transfer Function– · Write Software to Calculate Inverse Transfer Function
– · Analyse Diagonal or Row Dominance– · Calculate Parameters of the Controller
Dyadic Control (Eigenvalue-based Design )
• Calculate Eigenvalues of Multivariate Transfer Function (MATLAB)
• Calculate Parameters of Dyadic Controller
Emmanuel B. Tanyi
Third US-Africa Research and
Education Collaboration WorkshopAbuja, Nigeria, December 13-15, 2004
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CONTROLLER DESIGN STRATEGIES cont.
First Order Approximation Method•
– · Simulate Closed-Loop System (without Controller) to generate Time Response Curves
– · Derive Approximate First Order Models from the Time Response Data
– · Calculate the Parameters of the Controller
Emmanuel B. Tanyi
Third US-Africa Research and
Education Collaboration WorkshopAbuja, Nigeria, December 13-15, 2004
29
PERSPECTIVES
• The modelling aspect of the project is fairly complete, but Control Systems Design aspect is still in progess. This involves four Aspects :-– - Inverse Nyquist Array Controller
– - Dyadic Controller
– - First Order Approximation Controller
– - Evaluation of the Performance of the Controllers (MATLAB Simulation )
Emmanuel B. Tanyi
Third US-Africa Research and
Education Collaboration WorkshopAbuja, Nigeria, December 13-15, 2004
30
INFORMATION TECHNOLOGY
Real-time Applications for Control of
Power Networks
Object-Oriented Modelling of Automatic
Control Systems
Simulation of Hybrid Control Systems
Emmanuel B. Tanyi
Third US-Africa Research and
Education Collaboration WorkshopAbuja, Nigeria, December 13-15, 2004
31
REAL-TIME APPLICATIONS FOR CONTROL OF POWER NETWORKS
• 8 themes under Exploration :
1. Multi-tasking Operating Systems for Foreground- Background Control tasks
2. Implementation of Packages in JAVA and C++
3. Concurrent Execution of Packages using the technique of Multi-threading
4. Real-time Interface for Power System Control
5. Algorithms for the Implementation of State Observers
6. Digital Filters
7. Client-server Applications in Control
8. Communication Protocols for Real-time
Emmanuel B. Tanyi
Third US-Africa Research and
Education Collaboration WorkshopAbuja, Nigeria, December 13-15, 2004
32
OBJECT-ORIENTED MODELLING OF AUTOMATIC CONTROL SYSTEMS
• Application of the Unified Modelling Language (UML) to Automatic Control Systems:
Discrete Systems :– - Class hierarchies for Grafcet (Function Chart) Objects– - Interactive Grafcet Construction– - Inference Engine for Grafcet Execution– - Class hierarchies for Petri Net Objects– - Interactive Petri Net Construction– - Inference Engine for Petri Net Execution
Continuous Systems :– Class Hierarchies for Equations– Objects for Block Diagram Construction
Emmanuel B. Tanyi
Third US-Africa Research and
Education Collaboration WorkshopAbuja, Nigeria, December 13-15, 2004
33
FIG. 5 : OBJECTS HIERARCHY FOR THE
GRAFCET PARADIGM
1
Conditionne
Décrit E
TA
PE
TR
AN
SIT
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AC
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N
RE
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ITE
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AR
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IMPL
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EN
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(pa
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PLA
GE
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Q
Emmanuel B. Tanyi
Third US-Africa Research and
Education Collaboration WorkshopAbuja, Nigeria, December 13-15, 2004
34
SIMULATION OF HYBRID CONTROL SYSTEMS
Development of a Repertoire of Object Classes for Simulation of Sequential systems
Development of a Repertoire of Object Classes for Simulation of Continuous Systems
Modelling of Interactions between continuous and Discrete Components of a Hybrid System
Development of Continuous and Discrete Simulators
Concurrent Execution of the Two Simulators using Multi-threading
Application to Rolling Mill
Application to Power Systems ( Scheduling + Control)
Emmanuel B. Tanyi
Third US-Africa Research and
Education Collaboration WorkshopAbuja, Nigeria, December 13-15, 2004
35
FIG. 6 : HYBRID SIMULATION OF ROLLING MILL
Emmanuel B. Tanyi