ELG 4152 MODERN CONTROL SYSTEM PROJECT
Predictive Feed forward Control for a Hydroelectric Plant
by
Amirul Bhuiya
Norman Escobar
Omar Faroque
Hung Pham
for
Professor: Riadh Habash
TA: Fouad F. Khalil
March 28, 2007
Introduction
The purpose for this project is to replicate the work done by Dewi Jones
and Sa’ad Mansoor in their paper “Predictive Feedforward Control for
a Hydroelectric Plant”, IEEE TRANSACTIONS ON CONTROL SYSTEMS TECHNOLOGY,
VOL. 12, NO. 6, NOVEMBER 2004
Their work consisted of simulating the Dinorwig hydroelectric plant in the
U.K. and improving its performance by designing a feed forward loop to
better respond to frequency variations on the electrical grid.
Their design allowed them to improve the system response time by up to 3
seconds depending on the operating point of the hydroelectric plant and the
load on the system.
Introduction
The following references were used in the development of our project:
D.I. Jones, “Dynamic system parameters for the National Grid”, IEE Proc.-Gener. Transm. Distrib., Vol. 152, No. 1,
January 2005
In this paper Dr. Jones developed a generic model of the National grid
Dewi Jones, “Estimation of Power System Parameters”, IEEE TRANSACTIONS ON POWER SYSTEMS, VOL. 19,
NO. 4, NOVEMBER 2004.
In this paper Dr. Jones developed the parameters for estimating the low order dynamic model of the U.K. power system.
German Ardul Mu˜noz-Hern´andez,Dewi Jones, “MIMO Generalized Predictive Control for a Hydroelectric Power
Station”, IEEE TRANSACTIONS ON ENERGY CONVERSION, VOL. 21, NO. 4, DECEMBER 2006.
In this paper Dr. Ardul applies generalized predictive control to a multivariable model of the Dinorwig power plant.
Dewi Jones and Sa’ad Mansoor, “Predictive Feedforward Control for a Hydroelectric Plant”, IEEE TRANSACTIONS
ON CONTROL SYSTEMS TECHNOLOGY, VOL. 12, NO. 6, NOVEMBER 2004
In this paper the authors use a feed-forward model to improve the Dinorwig power plant.
Sa'ad Mansoor , Thesis "Behaviour and Operation of Pumped Storage Hydro Plants” University of Wales, Bangor,
School of Informatics, July 2000.
In this thesis Dr. Mansoor developed a model of the Dinorwing power plant.
METHODOLOGY APPLIED
PROJECT SELECTION FROM IEEE PAPER
PAPER RESEARCH
EQUATION/MATERIAL ANALYSIS
DEVELOPMENT OF BASIC MODEL
DEVELOPMENT OF GUI AND TEST
SCRIPTS
IMPLEMENTATION AND TESTING
ANALYSIS OF RESULTS
Work Distribution
Amirul Bhuiya: Research power plant modeling, select most appropriate model to use and develop
proper plant parameters for model implementation
Norman Escobar: Implement the system model, the GUI interface and perform related tests using
MATLAB and its Simulink and GUIDE toolboxes
Omar Faroque: Research a viable grid model, develop and simplify for implementation
Hung Pham: Research feed forward systems, develop a feed forward loop to be incorporated into
the system model.
Each member wrote the corresponding sections in the report and in the development of the
presentation.
General Background
Power Plant
DAM
Water
Generator
Transformer
Turbine sinning by water flow
General Background
Water Outlet
Water Entrance
From Tunnel
General Background
Dinorwig Electric Generator
General Background
LV/Secondary side
HV/ Primary Side
Breather
Oil Tank
10MVA
Oil Filled Power
Transformer
General Background
Power Grid
• The power grid consists of many interconnected
power generating stations
• Grid circuit load is shared by interconnected power
station.
• Interconnected power generating stations have to
maintain identical Voltage, Phase difference, and
Frequency with each other.
General Background
CB
Power
Generation
Plant
11KV
Circuit
Breaker
C
O
N
S
X-former
CB
Power
Generation
Plant
11KV
Circuit
Breaker
Transmission
Line
Consumer
Consumer
X-former
220KV
Circuit
Breaker
220KV
Circuit
Breaker
CB
X-former
Consumer
CB
Power Grid
X-former
General Background
What causes grid frequency variations?
1.
2.
Load variation on the GRID overloads the generators causing their
rotation (RPM) to slow down.
Lightning creates tremendously high voltages on the Transmission
lines with unknown frequencies producing resonant frequencies on
the HT line..
Why the need to maintain a constant grid frequency?
1.
2.
Frequency variations can damage or disrupt sensitive electronic
equipment.
Motors, variable speed drives, switching power supplies etc… rely
on constant frequency.
Frequency deviation to power demand relationship
Freq. Deviation
Power Demand
MODEL DEVELOPMENT
Model of Hydroelectric Plant and Electric Grid
MODEL DEVELOPMENT
PI Controller
Guide Vane Servo model
MODEL DEVELOPMENT
Hydrodynamic model
Turbine/Generator
MODEL DEVELOPMENT
Grid
Feedback
MODEL DEVELOPMENT
Feed forward model
FEED FORWARD MODEL
Required Feed Forward Transfer Function = Inverse of Gp (According a paper propose by G. C. Goodwin)
RESULTS
GUI developed to perform tests on system model
RESULTS
• The GUI was designed to control the
turbine/generator parameters
• It provides control of the amount of generators
running at any given time
• It allows the addition of disturbance that models the
grid power demand change
• It allows control of feed forward and feedback loops
to test performance
RESULTS
• Simulation of system with one
generator running, standard
turbine/generator parameters and no
grid disturbance with feedback only
RESULTS
• Simulation of system with all
generators running, standard
turbine/generator parameters, 15MW
grid disturbance, feedback and feed
forward enabled
RESULTS
# of
Generators
Response time (s)
With Feedback
only
With Feed
Forward
With
Disturbance
1
2.24
2.24
2.27
2
3.36
3.36
3.3
3
4.43
4.43
4.12
4
5.44
5.44
5.42
5
6.36
6.36
5.5
6
7.22
7.22
5.9
RESULTS
Response time (s)
With Feedback
only
With Feed
Forward
With
Disturbance
Normal Operation
3.15
3.15
0
High Load
9.85
9.85
0
RESULTS
Normal Operation with grid incorporated
RESULTS
High Demand with grid incorporated
Conclusion
•
•
•
•
The objective of this project was to simulate the hydroelectric plant model by Dewi Jones and Sa’ad
Mansoor which incorporated a feed forward path in an existing feedback control system. Here, we have
successfully simulated the idea behind the feed forward control system of 6 hydro power generator.
As the results indicate, with feedback alone, the system is stable and works within requirements and
specifications. However, the electrical power response to demand variations is very important with
respect to delivery time and frequency variations (every second counts). This is where the feed forward
theory comes into the design. For this particular control system, feedback improved the steady state
error, the settling time, the system’s overall stability, and the system’s overshoot but not the system’s
delivery time (when the power is actually being deliver to the consumer).
The clear advantages of feed forward theory for this particular system are:
1. Improve delivery time
2. Cheap to implement into existing system (avoiding a new design from scratch)
The disadvantage of this particular feed forward model is that every new Grid (city) needs a new feed
forward path because different cities have different load or demand characteristics.
The main problem that we encounter during the investigating of this project is the simulation of the more practical feed
forward design propose by the paper. This is due the fact that we do not have the exact parameter values of the Turbine
generator and the exact transfer function for the Grid (city) that the paper has access to. However, by simulating our
developed feed forward design it is easy to demonstrate that feed forward theory is something that should be consider in
all control system designs.