Guided by: Presented by:Mr. Sumeet Sehrawat Komal WadhwaDept. of EEE M.Tech Power Systems(Weekend)ASET, NOIDA A2327313001

CONTROLLING FREQUENCY DEVIATIONS IN INTERCONNECTED POWER SYSTEM USING SMART

TECHNIQUES

OBJECTIVE 1) Study of load frequency control in interconnected power

system. 2) Study of conventional and advanced controllers using

Matlab Simulation.3) Comparative study of different controllers. 4) Result comparison.

WHY FREQUNCY CONTROL IS REQUIRED?The speed of the alternating current motors depends on the frequency of the

power supply. There are situations where speed consistency is expected to be of high order.

The accuracy of the electric clocks are dependent on the frequency of the supply.

If the normal frequency is 50 Hertz and the system frequency falls below 47.5 Hertz or goes up above 52.5 Hertz then the blades of the turbine are likely to get damaged so as to prevent the stalling of the generator .

Due to the subnormal frequency operation the blast of the ID and FD fans in the power stations get reduced and thereby reduce the generation power in the thermal plants.

SINGLE AREA SYSTEM (Isolated Power System)

Peak time = l.223 Rise time = 0.4l8 Settling time =

6.8 Percent overshoot = 54.80

SINGLE AREA SYSTEM• With the primary Load Frequency Control (LFC) loop a change in the system

load will result in a steady state frequency deviation , depending on the governor speed regulation.

• In order to reduce the frequency deviation to zero an integral controller is connected to provide reset action on the load reference setting to change the speed set point.

• The integral controller gain must be adjusted for a satisfactory transient response.

SIMULATION RESULT

Load Frequency Control of single area with PID Controller

Load Frequency Control of two Area System

Load Frequency control of Three Area System

1

0.4s+1

Transfer Fcn9

1

0.08

Transfer Fcn8

1

0.25s+1

Transfer Fcn7

1.918

s

Transfer Fcn6

1

0.3s+1

Transfer Fcn5

1

8s+0.9

Transfer Fcn4

1

10s+0.6

Transfer Fcn3

1

0.5s+1

Transfer Fcn2

1.918

s

Transfer Fcn17

1.861

s

Transfer Fcn16

1.861

s

Transfer Fcn15

1.720

s

Transfer Fcn14

1.720

s

Transfer Fcn13

1

0.6s+1

Transfer Fcn12

1

0.0625

Transfer Fcn11

1

12s+0.8

Transfer Fcn10

1

0.05

Transfer Fcn1

1

0.2s+1

Transfer Fcn

z3

To Workspace3

z2

To Workspace2

z1

To Workspace1

z

To Workspace

Step2

Step1

Step

Scope2

Scope1

Scope

Clock1

Clock

0 10 20 30 40 50 60 70 80 90 100-0.03

-0.025

-0.02

-0.015

-0.01

-0.005

0

0.005

0.01

0.015for area 1 df1 vs t

time(s)

df1(

hz)

0 10 20 30 40 50 60 70 80 90 100-8

-6

-4

-2

0

2

4

6

8

10x 10

-3 for area 2 df2 vs t

time(s)

df2(

hz)

0 10 20 30 40 50 60 70 80 90 100-0.03

-0.025

-0.02

-0.015

-0.01

-0.005

0

0.005

0.01for area 3 df3 vs t

time(s)

df3(

hz)

Simulation result for Area2

Simulation result for Area1

Simulation result for Area3

Control Techniques used:Artificial Neural Network Controller

The ANN controller architecture being utilized here is a Model Reference Neural Network to predict the effect of controller changes on plant output, which allows the updating of controller parameters. In the study, the frequency deviations, tie-line power deviation and load perturbation of the area are chosen as the neural network controller inputs. The outputs of the neural network are the control signals, which are applied to the governors in the area.

Interna1 Structure 0f Weights in 1ayers 0f NN C0ntr011er.

Fuzzy Inference SystemBetter performance of the system can be accomplished by utilizing fuzzy logic

which is more productive way for load frequency controller. The fuzzy inference system designed using MATLAB GUI consists of two phases, initially in one fuzzy unit where the Area control error(ACE) and derivative area control error (ΔACE) are set as input parameters and then the knowledge based training is applied accordance to the rules, the output was the control action.

Load Frequency control of single Area Power System with ANN Controller

Load Frequency control of two Area Power System with ANN Controller

System Model with Fuzzy Logic Controller

Load Frequency Control of Three Area System using Fuzzy tuned PI Controller

FGPI

FGPI

FGPI

1

Tt3.s+1

1

Ts3.s+1

Kp2

Tp2.s+1

1

Tt2.s+1

1

Ts2.s+1

Kp1

Tp1.s+1

Kp3

Tp3.s+1

1

Tt1.s+1

1

Ts1.s+1IN OUT

IN OUT

IN OUT

1s

1s

1s

-K-

-K-

B2

-K-

-K-

-K-

B1

-K-

B3

-K-

-K-

-K-

Simulation result for area 1

Simulation result for area 3

Simulation result for area 2

CONCLUSION AND FUTURE SCOPEConclusion:

 The research provides a practical means for balancing frequency oscillations in an interconnected power system through an HVDC link. By appropriate usage of the system integrations as regulatory medium, a new application of HVDC link to stabilize frequency oscillations in AC power systems was developed. The proposed controller is highly efficient in restraining the frequency oscillations and can also be integrated with the traditional governors productively. The work described in this explained the modeling of three area power system using FLC containing three thermal power generators. Different types of controller were used to improve the transients that occurs in the system due to frequency variations .The simulation results using FLC gives the better result as compared to other controller in an efficient manner..

Future scope: For further study, the proposed control design of HVDC link can be extended to stabilization of frequency oscillations in a multi-area interconnected power system with any configuration, in integration with different intelligent techniques including longitudinal and radial loops.

REFERENCES[l] D.P Kothari ;I J Nagrath , Modern Power System Analysis [2] P Kundur, Power System Stability and Control [3] D. Das,Automatic Generation Control In Restructured Scenario, Electrical Power System[4] Prof. S.N Singh, Video :lecture , Power system operation and control[4] Load frequency control of a realistic power system with multi-source power generation K.P. Singh Parmar , S. Majhi , D.P. Kothari [5] R N Deo; S P Jaiswal; M. Venkentasvalru Naik :Fuzzy logic based automatic load frequency control of multi area system .[6] M. Suman, M. Venu Gopala Rao, G. R. S. Naga Kumar and O. Chandra Sekhar, "Load frequency control of three unit interconnected multimachine power system with PI and fuzzy controllers," Advances in Electrical Engineering (ICAEE), 2ol4 International Conference on, Vellore, 2ol4[7] N. E. Y. Kouba, M. Menaa, M. Hasni and M. Boudour, "Load Frequency Control in multi-area power system based on Fuzzy Logic-PID Controller," Smart Energy Grid Engineering (SEGE), 2ol5 IEEE International Conference on, Oshawa, ON, 2ol5.[8] V. S. Sundaram and T. Jayabarathi, "Load Frequency Control using PID tuned ANN controller in power system," Electrical Energy Systems (ICEES), 2oll lst International Conference on, Newport Beach, CA, 2oll.

Continue…[9] R. Umrao, S. Kumar, M. Mohan and D. K. Chaturvedi, "Load Frequency Control methodologies for power system," Power, Control and Embedded Systems (ICPCES), 2ol2 2nd International Conference on, Allahabad, 2ol2.[lo] A. Safaei, H. M. Roodsari and H. A. Abyaneh, "Optimal load frequency control of an island small hydropower plant," Thermal Power Plants (CTPP), 2oll Proceedings of the 3rd Conference on, Tehran, 2oll.[ll]Fuzzy Logic Toolbox :Fuzzy Reference http://in.mathworks.com/products/fuzzy-logic/features.html#working-with-the-fuzzy-logic-toolbox[l2] Thesis: Implementation Of Fuzzy Logic Controller For Load Frequency Control In Two Area Power System ,Nit Rourkela[l3] K.S.S Ramakrishna , P Sharma ,T.S Bhatti: Automatic generation control of interconnected power system with diverse Sources of power generation[l4] S. K. Jain, A. Bhargava and R. K. Pal, "Three area power system load frequency control using fuzzy logic controller," Computer, Communication and Control (IC4), 2ol5 International Conference on, Indore, 2ol5