RELAY CO-ORDINATION WITH FAULT CALCULATION

MD. SAROWAR ALAM

ASSISTANT MANAGER (Technical)

SYSTEM PROTECTION AND METERING DIVISION

CHITTAGONG.

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

Objectives

To determine proper relay setting

To improve the system reliability

To avoid un-wanted tripping

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

Co-ordination of protective relays refers to co-relating the settings of various relays/protection systems for harmonious and selective operation.

CO-ORDINATION

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

Basic requirements of a good protection system include selectivity, discrimination, adequateness, stability, sensitivity, reliability and time characteristics .To achieve these desirable requirements proper co-ordination of relay settings is essential.

CO-ORDINATION

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

CO-ORDINATION

Neighboring protective zones overlap. Hence there is a need for co-ordinating the time settings so that only faulty part gets quickly disconnected without disturbances to healthy part .

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

TYPES OF CO-ORDINATION

1. Current Graded

2. Time Graded

3. Both Current and Time Graded

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

1. Current Graded

Current graded co-ordination means downstream has lower current setting than upstream.

Current

I3I2I1

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

Disadvantage of Current Graded

Although upstream has higher current setting, so it causes damage of equipment due to high current passing for long time.

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

2. Time Graded

Time graded co-ordination means downstream has lower time setting than upstream.

Time

t3t2t1

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

Disadvantage of Time Graded

Although upstream has higher time setting, so when fault occurs near to the bus then high current pass through equipment for long time and causes damage of equipment.

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

3. Time and Current Graded

The principle of Both Time and Current Graded is that higher the current lower the relay trip time.

Tim

e

CurrentPrepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

1. Fault calculation

2. Time grading (Grading Margin) 3. Switching transient current (Inrush)

NECESSARY FACTORS FOR CO-ORDINATION

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

Grading Margin

Operating time difference between two devices to ensure that downstream device will clear fault before upstream device trips.

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

Grading Margin includes

I. Breaker opening time

II. Allowance for errors

III. Relay overshoot time

IV. Safety margin

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

• Traditional (Grading margin - between relays)Breaker opening time - 0.10 Sec.Allowance for errors - 0.15 SecRelay overshoot - 0.05 Sec.Safety margin - 0.10 Sec.Total - 0.40 Sec

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

Fault Calculation Procedure

Two Methods:

I. Per Unit method (100MVA Base)

II. MVA method (No Base MVA)

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

Per Unit method

)Z2(Z3

V3

ZZZZZZ

VZ3I:fault G --

)ZZ(Z3

V3

ZZZ

V3I:fault G -

I2

3

ZZ

V3I:fault -

Z3

V

Z

VI:fault 3

-:equation lfundamenta Some

01

P-P

022101

N-P2f

021

P-P

021

N-Pf

3f21

N-Pf

1

P-P

1

N-Pf

+=

++=ϕϕ

++=

++=ϕ

=+

=ϕϕ

==ϕ

ϕ

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

Per Unit method

Z ckt of No.

)( Z Z

Z ckt of No.

)( ZZ Z: LineFor

100MVA XF

MVA Base%Z :r TransformeFor

: Impedances P.U.

21.1100M

11k : 11kV

89.10100M

33k : 33kV

24.174100M

132k : 132kV

: Base)(100MVA Impedances Base

Base

00

Base

121

2

2

2

×Ω=

×Ω==

××

Ω=

Ω=

Ω=

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

Per Unit method

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

Per Unit method

p.u. 0.09427T ||T

p.u. 1855.010063

10069.11

100 MVA FX

MVA BaseZ%ZZZT

p.u. 1917.010063

10008.12

100 MVA FX

MVA BaseZ%ZZZT

: Impedance ransformerT kV33/132

p.u. 0807.003086.0224.174kA21.93

kV1323Z2

ZI3

V3Z

.u.p 03086.024.174kA17.143

kV132

ZI3

VZZ

: Impedance ourceS

21

0212

0211

1

BaseG

PP0

Base3

PP21

=

=×

×=×

×===→

=×

×=×

×===→

=×−××

×=−××

=

=××

=××

==

−ϕ

−

ϕ

−

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

Per Unit method

p.u. 0.248T ||T

p.u. 495.010020

10090.9

100 MVA FX

MVA BaseZ%ZZZT

p.u. 497.010020

10094.9

100 MVA FX

MVA BaseZ%ZZZT

: Impedance ransformerT kV11/33

.u.p 38085.089.102

295.8

Zckt of .No

ZZ

.u.p 12695.089.102

765.2

Zckt of .No

ZZZ

: Impedance Line 3kV3

3231

02132

02131

Base

00

Base

121

=

=××=

××===→

=××=

××===→

=×

=×

=

=×

=×

==

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

Per Unit method

kA 73.1689.10)Z3(Z3

V3I:fault G --

kA 23.1589.10)Z3(2Z3

V3I:fault G -

kA 1.12I2

3I:fault -

kA 98.1389.10)Z(Z3

VI:fault 3

-:Fault Bus 33kVHalisahar

21

21

21

T ||1T1source

P-Pf

T ||1T1source

P-Pf

3ff

T ||1T1source

P-Pf

=×+

=ϕϕ

=×+

=ϕ

==ϕϕ

=×+

=ϕ

ϕ

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

Per Unit method

kA 365.489.10)Z2ZZ3(Z3

V3I:fault G --

kA 359.589.10)ZZ2Z3(2Z3

V3I:fault G -

kA 009.6I2

3I:fault -

kA 93.689.10)ZZ(Z3

VI:fault 3

-:Fault Bus 33kVRampur

0Line1LineT ||1T1source

P-Pf

0Line1LineT ||1T1source

P-Pf

3ff

1LineT ||1T1source

P-Pf

21

21

21

=×+++

=ϕϕ

=×+++

=ϕ

==ϕϕ

=×++

=ϕ

ϕ

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

Per Unit method

kA 807.1521.1)Z3ZZ(Z3

V3I:fault G --

kA 61.1221.1)Z3Z2Z2(2Z3

V3I:fault G -

kA 088.9I2

3I:fault -

kA 49.1021.1)ZZZ(Z3

VI:fault 3

-:Fault Bus 11kVRampur

323121

323121

323121

T ||1T1LineT ||1T1source

P-Pf

T ||1T1LineT ||1T1source

P-Pf

3ff

T ||1T1LineT ||1T1source

P-Pf

=×+++

=ϕϕ

=×+++

=ϕ

==ϕϕ

=×+++

=ϕ

ϕ

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

Per Unit method

15.8074.36516.73φ – φ - G

12.6145.35915.23φ - G

9.0886.00912.1φ - φ

10.496.9313.983φ

Rampur 11kV Bus Fault (kA)

Rampur 33kV Bus Fault (kA)

Halisahar 33kV Bus Fault (kA)

Fault Type

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

FEATURES OF THE SOFTWARE

1. Graphical view of single line diagram.

2. Fault Calculation for different configuration.

3. Relay setting flexibility.

4. Curve plotting to cross check the co-ordination

5. Finally shows the settings sheet.

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

Diagram-1

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

Diagram-2

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

Diagram-3

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

Diagram-4

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

Co-ordination

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

Co-ordination

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

Curve Plotting

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

How to use this software ?

Let's have a look => =>

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

Setting Sheet

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

THANKS TO ALL

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012

Any Question???

Prepared by-

MD. SAROWAR ALAM,ASSISTANT MANAGER,

SPMD-CTG, PGCB.

08-11-2012