EFP Basics

Technology and SolutionsProtection and Substation Automation

ABB©AB

B S

witz

erla

nd L

td.-

1E

FP_b

asic

s / 2

003-

04-0

1 / R

W

Topic:

END FAULTPROTECTIONAPPLICATION

BASICS BASICS

ABB©AB

B S

witz

erla

nd L

td.-

2E

FP_b

asic

s / 2

003-

04-0

1 / R

WTopic Objectives

r Definition Protection Zone - Physical Zone

r Definition End- Fault Conditionr Fault clearance without EFP

r Fault evaluation

r EFP applicationr Fault clearance with EFP

r End- Fault Condition in a bus- coupler

r CB auxiliary circuitsr Modern protection systems

r BBP - additional CB functionality on feedersr Future standards

Objectives

ABB©AB

B S

witz

erla

nd L

td.-

3E

FP_b

asic

s / 2

003-

04-0

1 / R

W

1 CT

Definition Protection Zone - Physical Zone

2 CTs (overlapped protection zones)

busbar zone

(physical)

line zone

(physical)

protection zone

protection zone

protection zone

protection zone

ABB©AB

B S

witz

erla

nd L

td.-

4E

FP_b

asic

s / 2

003-

04-0

1 / R

WDefinition End- Fault Condition

1 CT

2 CTs (overlapped protection zones)

End - Zone

End - Zone

End - Fault

ABB©AB

B S

witz

erla

nd L

td.-

5E

FP_b

asic

s / 2

003-

04-0

1 / R

WBusbar Configurations

CT line side

CT bus side

CT overlapped

Selectivity

Speed

Selectivity

Speed

single or multiple busbar

1 1/2 breaker busbar

How will an End- Fault condition be cleared in different busbar

configurations (without any End-Fault Protection) ???

ABB©AB

B S

witz

erla

nd L

td.-

6E

FP_b

asic

s / 2

003-

04-0

1 / R

W

Bus

bar

Fault clearance (without EFP)

I. Multiple BB, CT line side

G

ABB©AB

B S

witz

erla

nd L

td.-

7E

FP_b

asic

s / 2

003-

04-0

1 / R

W

Line

G


I. Multiple BB, CT line side

ABB©AB

B S

witz

erla

nd L

td.-

8E

FP_b

asic

s / 2

003-

04-0

1 / R

W

Bus

bar

Line

G


II. Multiple BB, CT bus side

ABB©AB

B S

witz

erla

nd L

td.-

9E

FP_b

asic

s / 2

003-

04-0

1 / R

W

OC Back- up

Line

Dis

tanc

e

G



ABB©AB

B S

witz

erla

nd L

td.-

10E

FP_b

asic

s / 2

003-

04-0

1 / R

W

Bus

bar

Line

G


III. Multiple BB, CT overlapped

ABB©AB

B S

witz

erla

nd L

td.-

11E

FP_b

asic

s / 2

003-

04-0

1 / R

W

G


III. Multiple BB, CT overlapped

ABB©AB

B S

witz

erla

nd L

td.-

12E

FP_b

asic

s / 2

003-

04-0

1 / R

W

Line Distance

OC Back- up

OC Back- up


IV. 1 1/2 CB BB, CT line side

ABB©AB

B S

witz

erla

nd L

td.-

13E

FP_b

asic

s / 2

003-

04-0

1 / R

W

OC Back- up

OC Back- up


V. 1 1/2 CB BB, CT bus side

ABB©AB

B S

witz

erla

nd L

td.-

14E

FP_b

asic

s / 2

003-

04-0

1 / R

WFault clearance (without EFP)

VI. 1 1/2 CB BB, CT overlapped

ABB©AB

B S

witz

erla

nd L

td.-

15E

FP_b

asic

s / 2

003-

04-0

1 / R

W

CT line side

CT bus side

CT overlapped

single or multiple busbar

1 1/2 breaker busbar

Fault Evaluation

++ very good

+ acceptable

- critical

Selectivity

Selectivity

Speed

Speed

++

++++

++

++

+ -

---

-

-

ABB©AB

B S

witz

erla

nd L

td.-

16E

FP_b

asic

s / 2

003-

04-0

1 / R

WFault Evaluation

Conclusion:

An additional protection function is required in CT bus side and 1 1/2 circuit

breaker configuration without overlapped CTs

!!!

ð End- Fault Protection Function

ABB©AB

B S

witz

erla

nd L

td.-

17E

FP_b

asic

s / 2

003-

04-0

1 / R

W

logic depending on the switchgear configuration (CT bus side, Line side;

1 1/2 CB)

feeder current

End- Fault Protection Function

EFP

&

I >

remote tripping

intertripping

t = EFP pick up time (higher than the highest possible arc extinguish time + safety time

CB opent

~120 ms

ABB©AB

B S

witz

erla

nd L

td.-

18E

FP_b

asic

s / 2

003-

04-0

1 / R

WFault clearance (with EFP)

How will an End- Fault condition be cleared in

different busbar configurations (with End- Fault Protection)

???

ABB©AB

B S

witz

erla

nd L

td.-

19E

FP_b

asic

s / 2

003-

04-0

1 / R

W

Bus

bar

Line

G

Fault clearance (with EFP)


ABB©AB

B S

witz

erla

nd L

td.-

20E

FP_b

asic

s / 2

003-

04-0

1 / R

W

G

Fault clearance (with EFP)


EFP

Intertripping

ð Fault cleared selectively !!!(~250ms)

ABB©AB

B S

witz

erla

nd L

td.-

21E

FP_b

asic

s / 2

003-

04-0

1 / R


IV. 1 1/2 CB BB, CT line side

EFPIntertripping

Remote trip


ABB©AB

B S

witz

erla

nd L

td.-

22E

FP_b

asic

s / 2

003-

04-0

1 / R


V. 1 1/2 CB BB, CT bus side

EFP


Intertripping

ABB©AB

B S

witz

erla

nd L

td.-

23E

FP_b

asic

s / 2

003-

04-0

1 / R

W

How will an End- Fault condition be cleared in a bus- coupler (without any

EFP)

???

End- Fault Condition in a Bus- Coupler

ABB©AB

B S

witz

erla

nd L

td.-

24E

FP_b

asic

s / 2

003-

04-0

1 / R

W

BB1

BB2


~ ~

ABB©AB

B S

witz

erla

nd L

td.-

25E

FP_b

asic

s / 2

003-

04-0

1 / R

WEnd- Fault Condition in a Bus- Coupler

ABB©AB

B S

witz

erla

nd L

td.-

26E

FP_b

asic

s / 2

003-

04-0

1 / R

W

⇒ by the coupler function of the

BUSBAR protection


ABB©AB

B S

witz

erla

nd L

td.-

27E

FP_b

asic

s / 2

003-

04-0

1 / R

W

r a bus- coupler

End Fault Protection application

r multiple BB configuration with CT bus sider 1 1/2 circuit breaker configuration without

overlapped CTs

Summery:An EFP function in strictly required in:

It is not required in:r configuration with overlapped CTs

It will reduce the tripping time in:r multiple BB configuration with CT line side

ABB©AB

B S

witz

erla

nd L

td.-

28E

FP_b

asic

s / 2

003-

04-0

1 / R

WCB auxiliary circuits

What “problem” will occur in case on a “switch

onto fault” situation???

ABB©AB

B S

witz

erla

nd L

td.-

29E

FP_b

asic

s / 2

003-

04-0

1 / R


CB open !!!

CB closing command

flash over before CB indicates closed

⇒ EFP will trip the BB wrongly

EFP enabled

I>

CT bus side

ABB©AB

B S

witz

erla

nd L

td.-

30E

FP_b

asic

s / 2

003-

04-0

1 / R


CB open !!!

CB closing command


⇒ EFP will trip the line remote end wrongly

EFP enabled

I>

CT line side

ABB©AB

B S

witz

erla

nd L

td.-

31E

FP_b

asic

s / 2

003-

04-0

1 / R

W

⇒ in case on a “switch onto fault situation” the EFP will generate a tripping signal before the closed indication appears

(flash- over in the circuit breaker)

CB auxiliary circuits

ABB©AB

B S

witz

erla

nd L

td.-

32E

FP_b

asic

s / 2

003-

04-0

1 / R


How can this be avoided???

ABB©AB

B S

witz

erla

nd L

td.-

33E

FP_b

asic

s / 2

003-

04-0

1 / R

W

⇒ the protection system must be informed in advance that the CB is going to be closed

⇒ by the (manual) close command of the CB

CB auxiliary circuits

ABB©AB

B S

witz

erla

nd L

td.-

34E

FP_b

asic

s / 2

003-

04-0

1 / R

W

logic depending on the switchgear configuration (CT bus side, Line side;

1 1/2 CB)

feeder current

End- Fault Protection Function

EFP

&I >

remote tripping

intertripping

t = EFP pick up time (higher than the highest possible arc extinguish time + safety time

CB opent

~120 ms

CB (manual)

close command

ABB©AB

B S

witz

erla

nd L

td.-

35E

FP_b

asic

s / 2

003-

04-0

1 / R

W

Phase

R S T

CB / isolator auxiliary circuits

CB open

CB closed

++

protection

system

NC aux.

contacts

Phase

R

S

T

NC aux.

contacts

+

CB closing

coil

CB (manual)

close commandCB close

order

ABB©AB

B S

witz

erla

nd L

td.-

36E

FP_b

asic

s / 2

003-

04-0

1 / R

WModern Protection Systems

The Busbar Protection and End Fault Protection Function could be

combined in one modern protection systems (e.g. REB500 / REB500sys)

How is it possible to reach additional SELECTIVITY in a CT line side configuration at an End- Fault

condition with an already OPEN CB

???

ABB©AB

B S

witz

erla

nd L

td.-

37E

FP_b

asic

s / 2

003-

04-0

1 / R

W

Bus

bar

CT line side configuration

G

Modern Protection Systems

ABB©AB

B S

witz

erla

nd L

td.-

38E

FP_b

asic

s / 2

003-

04-0

1 / R

W

⇒ by deactivating of the busbar protection function

current measurement in case of an open CB(only applicable in a

CT line side configuration)

Modern Protection Systems

ABB©AB

B S

witz

erla

nd L

td.-

39E

FP_b

asic

s / 2

003-

04-0

1 / R

WBusbar Protection - additional CB functionality

⇒ BBP will not trip because the current will not be measured

CB open !!!

EFP enabledcurrent not measured in the BBP !!!

⇒ EFP will trip the remote end

for B

BP

only

app

licab

le in

a

CT

line

side

con

figur

atio

n

ABB©AB

B S

witz

erla

nd L

td.-

40E

FP_b

asic

s / 2

003-

04-0

1 / R

W

What is very important if such a additional CB functionality is used

???

Busbar Protection - additional CB functionality

ABB©AB

B S

witz

erla

nd L

td.-

41E

FP_b

asic

s / 2

003-

04-0

1 / R

W

⇒ the (manual) close command of the CB has to be installed / commissioned absolutely correctly

Busbar Protection - additional CB functionality

⇒ if not, there is a high risk of maloperation of the BUSBAR PROTECTION in case of switch onto fault condition !!!

ABB©AB

B S

witz

erla

nd L

td.-

42E

FP_b

asic

s / 2

003-

04-0

1 / R

WSwitch onto Fault with missing CB close command⇒ BBP will trip wrongly because the out-flowing current is not measured

CB open !!!

EFP enabledcurrent not measured in the BBP !!!

⇒ EFP will trip wrongly because the current is measured and the CB indicates open

CB closing command


ABB©AB

B S

witz

erla

nd L

td.-

43E

FP_b

asic

s / 2

003-

04-0

1 / R

W

Documents

EFP Basics