Measurement, Modeling and Control of UAE Power System Voltage and Frequency Variations

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Measurement, Modeling and Control of UAE Power
System Voltage and Frequency Variations
United Arab Emirates University College of
Engineering Department of Electrical
Engineering Graduation Project II

• Student Name ID
• Helal Saeed Sabt 200005018
• Faisal Mohammed Ahmad 200005019
• Saeed Ahmad Mohammed 200005020
• Advisor
• Professor. Abdullah Ismail.

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Out line

• Introduction.
• Automatic Voltage Regulator (AVR).
• Load Frequency Controller (LFC).
• LFC Model for Two Areas Power System.
• LFC for Three Areas Power System.
• Combining AVR with LFC system.
• Conclusion.

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Introduction

• An electrical power system consists of many
  elements connected to form complex system capable
  of generating, transmitting and distributing
  electrical energy over a large geographical area.

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Introduction

• Power system stability requires a well designed
  controllers to regulate system
• variations.
• Voltage and frequency control actions needed to
  maintain system operating conditions.
• Automatic Generation Control actions take
  effect.

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Introduction

• Automatic Generation Control (AGC) is the name
  given to a control system having three major
  objectives
• 1.Hold system frequency at a specified value
  (50Hz in UAE).
• 2. To maintain the correct value of interchange
  power between control areas.
• 3. To maintain each unit's generation at the most
  economic value.

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Introduction

• Automatic Generation Control has more advantages,
  such as
• Increase Generation Ability by connecting two or
  more areas together.
• Improve ability of load variation recovery.
• More efficient for detecting and fixing power
  faults.

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Power Generation Mechanism

• Mechanical energy provide the needed motion
  (rotational) to produce electrical power.
• Generated using thermal energy such as steam,
  natural gas and nuclear and the little rest by
  hydro-mechanical such as water falls energy or
  wind.

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Elements Of AGC efficiency

• Load Frequency Controller (LFC).
• The Automatic Voltage Regulator (AVR).

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Aims of the project

• Design and simulate AVR.
• Design and simulate LFC.
• Design and simulate LFC for two areas power
  system.
• Design and simulate LFC for three areas power
  system.
• Combining AVR with LFC.
• Control the power of different areas.

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Automatic Voltage Regulator (AVR)
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Introduction for the AVR system

• What is the AVR system?
• Why we need the AVR system?
• Where its connect in the power system?
• What elements its consist of?

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The AVR system

• Make the system efficient.
• Consist of sensor, amplifier, exciter and
  generator.
• Deals with the reactive power.

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The AVR system

• This is diagram for AVR system and it shows where
  it is connected in the generation system

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Modeling and Simulation
Simple AVR System
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Transfer function relating the generator terminal
voltage Vt(s) to the reference voltage Vref(s) is
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What is Happening in the AVR system?

• The amplifier comes first in the AVR system to
  amplify the error signal.
• Then the error signals alter the exciter and
  consequently the generator.
• The sensor sense the voltage output and send it
  to the transducer and the transducer send in the
  signal after comparing it to the amplifier.

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PID (proportional-integral-derivative)
The transfer function of a PID controller is
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• Advantages of PID
• Fast response and small error (due to the
  proportional gain).
• - Reduced steady-state error (due to the
  integral gain).
• - Reduced overshoot (due to the derivative
  gain).
• Disadvantages of PID
• - There is no formal way to determine the best
  PID gains.

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Simple AVR Model Simulink
Delta V
Delta V
Time (s)
Time (s)
Input signal (Step Function)
Output response from model
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Steady State error 1 0.96 0.04. Overshoot
1.09 1 0.09. Settling Time 4s.
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AVR with PID Controller
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Delta V
Delta V
Time (s)
Time (s)
Case 2( Kd0.5,Ki 0.5,Kp0.5).
Case 1( Kd0.1,Ki0.1,Kp1).
Delta V
Delta V
Time (s)
Time (s)
Case 4( Kd1,Ki3,Kp4).
Case 3( Kd0.2,Ki0.5,Kp 3).
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Steady State Error Settling Time (s) Overshoot Kp Ki Kd Cases
0.001 3 0.003 1 0.1 0.1 1
0.4 10 0.4 0.5 0.5 0.5 2
0.01 4 0.4 3 0.5 0.2 3
0.01 5 0.17 4 3 1 4
The case 1 is the best case because it has less
time settling, less overshoot and less steady
state error.
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• Load Frequency Control (LFC)

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Load Frequency Control (LFC)

• The main problems of control in the large power
  system are
• Active Power.
• Reactive Power.
• Active power control is closely related to
  frequency control.
• The frequency has an inverse relationship with
  the load that is changing continually.

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Load Frequency Control (LFC)

• Feedback.
• Sensor.
• Frequency fixed.
• Frequency of UAE power system 50 Hz

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Load Frequency Control (LFC)

• Analysis of LFC
• High load (Air conditions, machines) ? High
  pressure on
• system ? Decreasing in frequency of the load (lt
  50 0.05Hz) ?
• System is unstable.
• To return the value of load frequency to its
  normal
• 1) The output will multiply with the value of KG
  (speed regulation) then, multiply it with
  governor delay.
• 2) There will be a command which tells control
  valve to control the pushing of fuel.
• 3) More mechanical power to turbine ? More
  electrical power ? Frequency of the load will
  increase to its normal value ? System is stable.

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Load Frequency Control (LFC)

• Model of LFC

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Load Frequency Control (LFC)

• Modeling Simulation

Typical LFC Model
Name TCV TT K D
Value 0.2 sec 0.5 sec 0.8 20
constant values in LFC
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Load Frequency Control (LFC)

• Frequency response of LFC

Delta f (Hz)
Time (sec)

• It is not stable.

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Load Frequency Control (LFC)

• Improvement of LFC
• Adding PID controller to the LFC.

PID Controller.
PID parameters effects (Ki, Kd, Kp)
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Load Frequency Control (LFC)

• Model of LFC after adding PID Controller

Simulink diagram for LFC with PID control system
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Load Frequency Control (LFC)

• LFC response with different values of PID
  parameters

Delta f (Hz)
Delta f (Hz)
Time (sec)
Time (sec)
LFC response for (Kp 1, Ki 1, Kd 1)
LFC response for (Kp 1, Ki 0.3, Kd 1)
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Load Frequency Control (LFC)

• LFC response with different values of PID
  parameters

Delta f (Hz)
Delta f (Hz)
Time (sec)
Time (sec)
LFC response for (Kp 1, Ki 0.3, Kd 0.6)
LFC response for (Kp 2, Ki 0.8, Kd 1.1)
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Load Frequency Control (LFC)

• The output result of undershoot, settling time
  and steady- state error for different values of
  PID parameters

Kp Ki Kd Undershoot Settling time Steady- state error
1 1 1 -0.012 gt10 -0.002
1 0.3 1 -0.014 11 -0.0015
1 0.3 0.6 -0.015 10 -0.0011
2 0.8 1.1 -0.009 6 -0.0001
- Last value of PID controller parameter is the
best one.
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LFC Model for Two Areas Power System
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LFC Model for Two Areas Power System
LFC Model for two areas without integral
controller
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LFC Model for Two Areas Power System
Outputs figures (?f1, ?f2, ?Pt12)
Delta f (Hz)
Delta f (Hz)
Time (sec)
Time (sec)
?f2
?f1
Delta f (Hz)
?Pt12
Time (sec)
The system is not stable.
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LFC Model for Two Areas Power System
LFC Model for two areas with Integral Controller
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LFC Model for Two Areas Power System
For (ki1 0.02 ki2 0.01)
Figures for outputs (?f1, ?f2, ?Pt12) with
Integral Controller
Delta f (Hz)
Delta f (Hz)
Time (sec)
Time (sec)
?f2
?f1
Delta f (Hz)
Time (sec)
?Pt12
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LFC Model for Two areas
LFC Model for Two Areas Power System
For (ki1 0.1 ki2 0.02)
Delta f (Hz)
Delta f (Hz)
Time (sec)
Time (sec)
?f2
?f1
Delta f (Hz)
Time (sec)
?Pt12
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LFC Model for Two Areas Power System
For (ki1 0.42 ki2 0.019)
Delta f (Hz)
Delta f (Hz)
Time (sec)
Time (sec)
?f1
?f2
Delta f (Hz)
?Pt12
Time (sec)
The system is stable because output results go to
the reference point.
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Two Areas with Um Al Naar Substation
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Two Areas with Um Al Naar Substation

• Studying cases of LFC system of two area
• - Case 1 Area 1 and 2 are in the normal
  situation. (?P10 ?P20) .
• - Case 2 Area 1 is overloaded to more than 10
  of the normal limit, i.e. a step load disturbance
  of 0.1. Area 2 is in the normal situation. (?P1
  0.1 ?P2 0) .
• - Case 3 Areas 1 and 2 are overloaded to more
  than 10 of the normal limit, i.e. load
  disturbances of 0.1 for each area. (?P1 0.1
  ?P2 0.1) .
• - Case 4 Area 1 and 2 are overloaded to more
  than 10 and 20 of the normal limit, i.e.
  load disturbances of 0.1 and 0.2 respectively.
  (?P1 0.1 ?P2 0.2) .

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Two Areas with Um Al Naar Substation
Case 1 Area 1 and 2 are in the normal situation.
(?P10 ?P20)
Response for area 1 when ?P1 0 and ?P2 0.
Response for area 2 when ?P1 0 and ?P2 0.
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Two Areas with Um Al Naar Substation
Case 2 (?P10.1 ?P20)
Response for area 1 when ?P1 0.1 and ?P2 0.
Response for area 2 when ?P1 0.1 and ?P2 0.
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Two Areas with Um Al Naar Substation
Case 3 (?P10.1 ?P20.1)
Response for area 1 when ?P1 0.1 and ?P2 0.1.
Response for area 2 when ?P1 0.1 and ?P2 0.1.
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Two Areas with Um Al Naar Substation
Case 4 (?P10.1 ?P20.2)
Response for area 1 when ?P1 0.1 and ?P2 0.2.
Response for area 2 when ?P1 0.1 and ?P2 0.2.
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LFC Three Areas Power System
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Three-Area Power System
Area1
?Pt13
?Pt12
?Pt31
?Pt21
?Pt23
Area2
Area3
?Pt32
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Simple Block Diagram for 3-area Power System
Inputs
Variables
Outputs
3 Area Power System
?Pd1
?f1
?Pd2
?f2
?Pd3
?f3
?Pt12
?Pt23
?Pt13
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Three Area LFC system
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Output from LFC Three Area System
?f1 (Hz)
Time (sec)
Output from Area-1
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Output from LFC Three Area System
?f2 (Hz)
Time (sec)
Output from Area-2
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Output from LFC Three Area System
?f3 (Hz)
Time (sec)
Output from Area-3
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Combining AVR with LFC System
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Combining AVR with LFC System

• The connection between the AVR and the LFC
  systems only represented in some constants K1,
  K2etc.
• The main concentration in AGC system is the LFC
  part more than the AVR system.
• If the LFC system wasnt stable the AGC system
  will not be stable

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Simulation of the AGC system
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Simulation
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Result by using MATLAB
Kp0.1, Ki0.2 and Kd0.009
The response of the AGC the LFC part
The response of the AGC the AVR part
Overshoot 0.16
Overshoot 0.185
Response Time 12 s
Response Time 3.5 s
Steady state error 0
Steady state error 0
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The response of the AVR and LFC system separately
AVR
LFC
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From the previous example

• If the LFC system is not stable the AGC system is
  stable.
• If the AVR system wasnt stable it not meant to
  be that the AGC system isnt stable.

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Conclusion

• The purpose of AGC is the tracking of load
  variations while maintaining system frequency,
  net tie-line interchanges, and optimal generation
  levels close to specified values.
• AGC has more advantages than the previous
  technique such as, increasing generation ability,
  improve ability of load increase recovery, more
  efficient for detecting and fixing power faults,
  saving time.

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Conclusion

• LFC is used to regulate the output power of each
  generator at prescribed levels while keeping the
  frequency fluctuations within pre-specified
  limits.
• The study of AVR
• show what is the important of the
  proportional-integral-derivative action (PID)
  controller.
• The LFC system is much slower than the AVR due to
  the mechanical inertia constant in LFC.

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Conclusion

• If the LFC system is not stable the AGC system is
  not stable.
• If the AVR system wasnt stable it not mean that
  the AGC system isnt stable.

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• Thank You For Your Listening
• We Will Be Happy To Answer Your Questions