-:Supervisor :- -: Submitted by :-

Md. Abul kalam Sushil kumar (070912094)

Upawan kishor (0709120096)

Harshit Sihna (0609120022)

ObjectiveIn this project a fuzzy logic based faults

protection scheme for a transmission line will be studied and the technique will be developed on the basis of extension simulation studies carried out on the transmission line using MATLAB for different fault operating condition.

IntroductionTransmission line system is a large, geographically wide

distributed system.Fault on the transmission line is generally higher than that on

other component. Line fault are the most common faults. Transmission line faults be identified and to be determined

accurately and reliably in quick time.

What is fuzzy logic?"Fuzzy Logic is basically a multivalued logic. It is a different way of looking at the world. It is a superset of Boolean logic! Allows intermediate values to be defined

between conventional evaluations like yes/no, true/false, black/white, etc.

Notions like rather warm or pretty cold can be formulated mathematically and processed by computers."

Why use fuzzy logic?Fuzzy logic is conceptually easy to

understand.Fuzzy logic is flexible.Fuzzy logic is tolerant of imprecise data.Fuzzy logic can be blended with conventional

control techniques.Fuzzy logic is based on natural language.

Foundations of Fuzzy LogicEverything is vague to a degree you do not

realize till you have tried to make it precise.Fuzzy Sets. If-Then Rules. Fuzzify inputs Apply fuzzy operator to multiple part antecedents Apply implication method.

Fuzzy logic process

Fuzzy control systemFuzzificationRule-evaluationDefuzzification

Power system model

Faults parameters line length = 300 km; source voltages: source 1: v1 = 400 kV; source 2: v2 = 400 δ kV, where δ is∠ the load angle; source impedance (both sources): positive sequence impedance = 1.31 + j15.0; zero sequence impedance = 2.33 + j26.6; frequency = 50 Hz; transmission line impedance: positive sequence impedance = 8.25 + j94.5; zero sequence impedance = 82.5 + j308; positive sequence capacitance = 13 nF /km; zero sequence capacitance = 8.5 nF/km.

The Fault CurrentThe characteristic features of different types

of fault are found out in terms ofΔ1,Δ2 andΔ3,

r1 = max{rms(Ia)}/max{rms(Ib)},r2 = max{rms(Ib)}/max{rms(Ic)}r3 = max{rms(Ic)}/max{rms(Ia)}where Ia, Ib and Ic are the post-fault samples

of the three phase currents.

the normalized values of r1, r2 and r3

r1n = r1/max(r1, r2, r3)r2n = r2/max(r1, r2, r3)r3n = r3/max(r1, r2, r3)Finally, the differences of these normalised

values are found out as follows.Δ1 = r1n − r2n, Δ2 = r2n − r3n, Δ3 = r3n −

r1n

Calculation program for characteristic of faults Ia =input('enter ia') Ib =input('enter ib') Ic =input('enter ic') R1 = ia / ib R2 =ib /ic R3 =ic/ia I =r1; if(r2>r1) I =r2; end if(r3>r1&&r3>r2) I =r3; end R1n =r1/i R2n =r2/i R3n =r3/i D1 =r1n-r2n D2 =r2n-r3n D3 =r3n-r1n

Faults Characteristic measurementsfor AB fault

Faults Characteristic measurementsfor BC fault

Faults Characteristic measurementsfor CA fault

Faults Characteristic measurementsfor AG fault

Faults Characteristic measurementsfor BG fault

Faults Characteristic measurementsfor ABG fault

Faults Characteristic measurementsfor BCG fault

Faults Characteristic measurementsfor ACG fault

Faults Characteristic measurementsfor ABC fault

fault classification approach

Fault classification approach Developments of rules base for phase (line to line) faults:-1. If (d1 is low) and (d2 is high) and (d3 is medium) then

(output1 is AB) 2. If (d1 is medium) and (d2 is low) and (d3 is high) then

(output1 is BC) 3. If (d1 is high) and (d2 is medium) and (d3 is low) then

(output1 is CA) 4. If (d1 is medium) and (d2 is low) and (d3 is high) then

(output1 is CA) Where for phase faults “low” means a value between -1 to -

0.1 “medium” means a value between -0.45 to 0.45 and “high” means a value between 0.1 to 1.

Range of universe of discourse of membership function assigned for crisp output

Types of faults Range of membership function

AB 0 - 10

BC 10 - 20

CA 20 - 30

Dovelopments of rules base for phase to ground (single line to ground) faults: 1. If (d1 is high) and (d2 is medium) and (d3 is low) then (output1 is AG) 2. If (d1 is high) and (d2 is high) and (d3 is low) then (output1 is AG) 3. If (d1 is high) and (d2 is medium) and (d3 is medium) then (output1 is AG) 4. If (d1 is low) and (d2 is high) and (d3 is medium) then (output1 is BG) 5. If (d1 is low) and (d2 is high) and (d3 is high) then (output1 is BG) 6. If (d1 is medium) and (d2 is medium) and (d3 is medium) then (output1 is

BG) 7. If (d1 is high) and (d2 is low) and (d3 is high) then (output1 is CG) 8. If (d1 is medium) and (d2 is medium) and (d3 is high) then (output1 is CG) Where for phase faults “low” means a value between -1 to -0.25 “medium”

means a value between -0.05 to 0.25 and “high” means a value between 0.05 to 0.8.

Range of universe of discourse of membership function assigned for crisp output

Types of faults Range of membership function

AG 35 - 45

BG 50 - 60

CG 65 - 75

Developments of rules base for phase to ground (double line to ground) faults:

1. If (d1 is low) and (d2 is high) and (d3 is medium) then (output1 is ABG) 2. If (d1 is low) and (d2 is high) and (d3 is low) then (output1 is ABG) 3. If (d1 is medium) and (d2 is low) and (d3 is high) then (output1 is BCG) 4. If (d1 is low) and (d2 is low) and (d3 is high) then (output1 is BCG) 5. If (d1 is high) and (d2 is medium) and (d3 is low) then (output1 is CAG) 6. If (d1 is high) and (d2 is low) and (d3 is low) then (output1 is CAG) Where for phase faults “low” means a value between -1 to -0.1 “medium”

means a value between -0.45 to 0.45 and “high” means a value between 0.1

to 1.

 Range of universe of discourse of membership function assigned for crisp output

Types of faults Range of membership function

ABG 80 - 90

BCG 95 - 105

CAG 110 - 120

Output for different faultsd1 d2 d3 Crisp

outputType of fault

-0.9437 0.9973 -0.0536 5.1 AB

-0.0535 -0.9438 0.9973 20 BC

0.9973 -0.0535 -0.9438 24.9 AC

0.7482 0.2075 -0.9557 40 AG

-0.9557 0.7480 0.2077 55 BG

0.2076 -0.9557 0.7482 70 CG

-0.9375 0.9968 -0.0593 85 ABG

-0.0592 -0.9377 0.9968 100 BCG

0.9968 -0.0593 -0.9375 115 ACG

ConclusionA fuzzy logic based faults classification scheme is proposed to

identify all the ten types of shunt faults for the wide variation in operating conditions of a three phase transmission line.

The technique is developed on the basis of extensive simulation studies carried out on the transmission line using mat lab toolbox.

To apply the proposed technique three phase post fault current are measured(in R.M.S) at one end of the transmission line, generated for different of faults for a large number of test cases .In order to apply the technique features characteristic are extracted from the fault

References [1] Majid jamil , Md. Abul kalam and A. Q. Ansari, “fault

classification of three phase transmission line using fuzzy logic”, National conference on recent advances in electrical & electronic engineering (RAEEE-09), NIT Hamirpur , pp. 181-186.

[2] Huishing wang and W.W.L.keerrthibala “fuzzy- neuro approach to fault classification for transmission line protection,” IEEE transmission on power delivery, Vol. 13, no. 4,October 1998,pp. 1093-1102.

[3] R. N. Mahanty, P.B. Dutta Gupta, “A fuzzy logic based fault classification approach using current samples only,” Electric power system research ,77120073, pp. 501-507

[4] Jone Yen Rezalangari, “Fuzzy logic intelligence, control, and information”, Pearson Education.

[5] W.D. Stevenson, Jr. “ Elements of Power System Analysis”, Mc Graw Hill.

Thank you