ABB KLF Series Manual

Table of contents

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Jill

II

ABIP

Instruction

Leaflet

I

.

L

.

41

-

748

N

ABB

Power

T

&

D

Company

Inc

.

Relay

Division

Coral

Springs

,

FL

33065

Type

KLF

Loss

-

of

-

Field

Relay

50

/

60

Hertz

Effective

February

1984

Supersedes

I

.

L

.

41

-

748

M

dated

April

1980

^

Denotes

change

since

previous

issue

CAUTION

:

Before

putting

protective

relays

into

service

,

make

sure

that

all

moving

parts

operate

freely

,

inspect

the

contacts

to

see

that

they

are

clean

and

close

properly

,

and

operate

the

relay

to

check

the

settings

and

electrical

connections

.

COMPENSATOR

The

compensators

which

are

designated

and

Tc

are

two

-

winding

air

gap

transformers

(

Fig

.

2

)

.

The

primary

or

current

winding

of

the

long

-

reach

compensator

T

^

\

has

seven

taps

which

ter

-

minate

at

the

tap

block

.

They

are

marked

2.4

,

3.16

,

4.35

,

5.93

,

8.3

,

11.5

,

15.8

.

The

primary

wind

-

ing

of

the

short

-

reach

compensator

T

^

also

has

seven

taps

which

terminate

at

this

tap

block

.

They

are

marked

0.0

,

0.91

,

1.27

,

1.82

,

2.55

,

3.64

,

5.1

.

A

voltage

is

induced

in

the

secondary

which

is

proportional

to

the

primary

tap

and

current

magnitude

.

This

proportionality

is

established

by

the

cross

sectional

area

of

the

laminated

steel

core

,

the

length

of

an

air

gap

which

is

located

in

the

center

of

the

coil

,

and

the

tightness

of

the

laminations

.

All

of

these

factors

which

influence

the

secondary

voltage

proportionality

have

been

precisely

set

at

the

factory

.

The

clamps

which

hold

the

laminations

should

not

be

disturbed

by

either

tightening

or

loosening

the

clamp

screws

.

APPLICATION

The

KLF

relay

is

a

single

-

phase

relay

con

-

nected

to

the

ac

side

of

a

synchronous

machine

and

contains

three

units

connected

so

that

the

operation

of

two

units

sounds

an

alarm

warning

the

operator

of

a

low

excitation

condition

,

and

the

additional

operation

of

the

third

sets

up

the

trip

circuit

.

The

relay

can

be

applied

without

modification

to

all

types

of

synchronous

ma

-

chines

,

such

as

turbo

-

generators

,

water

wheel

generators

or

synchronous

condensers

.

The

KLF

relay

is

designed

for

use

with

3

phase

3

wire

voltage

supply

and

may

use

wye

or

delta

-

connected

voltage

transformers

.

On

circuits

with

4

wire

wye

-

connected

voltage

transformers

,

the

type

KLF

-

1

relay

may

be

used

to

increase

security

dur

-

ing

inadvertent

loss

-

of

-

potential

(

such

as

due

to

a

blown

potential

fuse

)

.

The

secondary

winding

is

connected

in

series

with

the

relay

terminal

voltage

.

Thus

a

voltage

which

is

proportional

to

the

line

current

is

added

vectorially

to

the

relay

terminal

voltage

.

AUTO

-

TRANSFORMER

CONSTRUCTION

The

auto

-

transformer

has

three

taps

on

its

main

winding

,

S

,

which

are

numbered

1

,

2

,

and

3

on

the

tap

block

.

A

tertiary

winding

M

has

four

taps

which

may

be

connected

additively

or

sub

-

tractively

to

inversely

modify

the

setting

by

any

value

from

—

15

to

+

15

percent

in

steps

of

3

per

-

cent

.

The

relay

consists

of

two

-

air

gap

transformers

(

compensators

)

,

two

tapped

auto

-

transformers

,

one

reactor

,

one

cylinder

-

type

distance

unit

,

direc

-

tional

unit

with

adjustable

reactor

,

an

under

-

voltage

unit

with

adjustable

resistor

,

telephone

relay

,

and

an

ICS

indicating

contactor

switch

.

All

possible

contingencies

which

may

arise

during

installation

,

operation

,

or

maintenance

,

and

all

details

and

variations

of

this

equipment

do

not

purport

to

be

covered

by

these

instructions

.

If

further

information

is

desired

by

purchaser

regarding

this

particular

installation

,

operation

or

maintenance

of

this

equipment

,

the

local

Asea

Brown

Boveri

representative

should

be

contacted

.

Courtesy of NationalSwitchgear.com

I

.

L

.

41

-

748

N

Rear

View

Fig

.

1

.

Type

KLF

Relay

2

Courtesy of NationalSwitchgear.com

I

.

L

.

41

-

748

N

SECONDARY

PRIMARY

LAMINATED

CORE

1

AIR

GAP

MDEt

TOiTAOE

M

;

T

'

UWCI

MIT

)

•

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(

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(

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.

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l

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l

£

IROICATIM

CONTACTOR

MITCH

CHASSIS

MCMTEO

SHORT

IM

MITCH

MM

-

M

V

.

O

.

C

.

20060

-

125

T

.

O

.

C

.

10000

-

210

V

.

O

.

C

.

V

RE

0

HANOI

t

TEST

SWITCH

UJHtFaT

T

,

j

7

JAM

/

i

»

•

1

»

NUTlH

»

iT

«

twmi

muiTin

1

CD

1

Cy

+

i

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©

©

(

t

)

f

8

‘

t

'

tMiHAl

FRONT

VIEW

I

Sub

.

7

185

A

181

Sub

.

8

184

A

958

Fig

.

2

.

Compensator

Construction

Fig

.

3

.

Internal

Schematic

of

Type

KLF

Relay

in

FT

41

Case

The

sign

of

M

is

negative

when

the

R

lead

is

above

the

L

lead

.

M

is

positive

when

L

is

in

a

tap

location

which

is

above

the

tap

location

of

the

R

lead

.

The

M

setting

is

determined

by

the

sum

of

per

unit

values

between

the

R

and

L

lead

.

The

ac

-

tual

per

unit

values

which

appear

on

the

tap

plate

between

taps

are

0

,

.

03

,

.

06

,

and

.

06

.

impedance

phasor

seen

by

the

relay

with

respect

to

its

characteristic

circle

.

Mechanically

,

the

cylinder

unit

is

composed

of

four

basic

components

:

A

die

-

cast

aluminum

frame

,

an

electromagnet

,

a

moving

element

assembly

,

and

a

molded

bridge

.

The

frame

serves

as

a

mounting

structure

for

the

magnetic

core

.

The

magnetic

core

which

houses

the

lower

pin

bearing

is

secured

to

the

frame

by

a

locking

nut

.

The

bearing

can

be

replaced

,

if

necessary

,

without

having

to

remove

the

magnetic

core

from

the

frame

.

The

auto

-

transformer

makes

it

possible

to

ex

-

pand

the

basic

ranges

of

the

long

and

the

short

g

reach

compensators

by

a

multiplier

of

j

^

relay

ohm

setting

can

be

made

within

+

1.5

per

-

cent

from

2.08

ohms

to

56

ohms

for

the

long

reach

and

from

.

79

ohms

to

18

ohms

for

the

short

reach

.

-

.

Any

The

electromagnet

has

two

sets

of

two

series

connected

coils

mounted

diametrically

opposite

one

another

to

excite

each

set

of

poles

.

Locating

pins

on

the

electromagnet

are

used

to

accurately

position

the

lower

pin

bearing

,

which

is

mounted

on

the

frame

,

with

respect

to

the

upper

pin

bear

-

ing

,

which

is

threaded

into

the

bridge

.

The

elec

-

tromagnet

is

secured

to

the

frame

by

four

moun

-

ting

screws

.

IMPEDANCE

TRIPPING

UNIT

The

distance

unit

is

a

four

pole

induction

cylinder

type

unit

.

The

operating

torque

of

the

unit

is

proportional

to

the

produce

of

the

voltage

quantities

applied

to

the

unit

and

the

sine

of

the

phase

angle

between

the

applied

voltages

.

The

direction

of

the

torque

so

produced

depends

on

the

3

Courtesy of NationalSwitchgear.com

I

.

L

.

41

-

748

N

=

ROTATION

A

,

B

,

C

D

C

TRIP

BUS

Ift

PCS

.

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t

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r

,

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DISTANCE

UNIT

VECTORS

FOR

(

001

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F

.

GENERATOR

OUTPUT

91

C

6

TA

^

*

z

DEVICE

NUMBER

CHART

GO

-

LOSS

OF

FIELD

RELAY

.

TYPE

KIF

D

-

DIRECTIONAl

UNIT

IN

TYPE

ILF

RELAY

ICS

-

INDICATING

CONTACTOR

SNITCH

IN

TYPE

ILF

RELAY

TA

-

LONG

REACH

COMPENSATOR

TC

-

SHORT

REACH

COMPENSATOR

V

-

VOLTAGE

UNIT

IN

TYPE

ILF

RELAY

X

-

TELEPNONE

RELAY

IN

TYPE

ILF

RELAY

Z

-

IMPEOANCE

UNIT

IN

TYPE

IlF

RELAY

43

-

ON

-

OFF

CUT

-

OUT

SNITCH

S

2

-

P

0

WER

CIRCUIT

BREAIER

a

-

BREAlER

AUXILIARY

SNITCH

1

C

-

BREAXER

TRIP

COIL

f

-

Jf

MA

+

CONTACT

/

CLOSES

*

-

FUSE

ILF

RELAY

SEPARATELY

FROM

ALL

OTHER

SECONDARY

BURDENS

•

'

'

BC

(

«

£

P

>

POLARIZING

COILS

—

OPERATING

COILS

43

SNITCH

(

OPTIONAL

)

-

IA

1

CONTACTS

OFF

ALAIN

*

TRIP

\

1

-

2

X

X

3

-

4

X

DIRECTIONAL

UNIT

VECTORS

FOR

1001

P

.

F

.

GENERATOR

OUTPUT

X

-

OENOTES

CONTACTS

CLOSED

Sub

.

10

290

B

607

Fig

.

4

.

External

Schematic

of

Type

KLF

Relay

tromagnet

and

the

magnetic

core

.

The

stops

are

an

integral

part

of

the

bridge

.

The

moving

element

assembly

consists

of

a

spiral

spring

,

contact

carrying

member

,

and

an

aluminum

cylinder

assembled

to

a

molded

hub

which

holds

the

shaft

.

The

hub

to

which

the

moving

-

contact

arm

is

clamped

has

a

wedge

-

and

-

cam

construction

,

to

provide

low

-

bounce

contact

action

.

A

casual

inspection

of

the

assembly

might

lead

one

to

think

that

the

contact

arm

bracket

does

not

clamp

on

the

hub

as

tightly

as

it

should

.

However

,

this

adjustment

is

accurately

made

at

the

factory

and

is

locked

in

place

with

a

lock

nut

and

should

not

be

changed

.

Optimum

contact

ac

-

tion

is

obtained

when

a

force

of

4

to

10

grams

pressure

applied

to

the

face

of

the

moving

contact

will

make

the

arm

slip

from

the

condition

of

reset

to

the

point

where

the

clamp

projection

begins

to

ride

up

on

the

wedge

.

The

free

travel

can

vary

between

15

°

to

20

°

.

The

bridge

is

secured

to

the

electromagnet

and

frame

by

two

mounting

screws

.

In

addition

to

holding

the

upper

pin

bearing

,

the

bridge

is

used

for

mounting

the

adjustable

stationary

contact

housing

.

This

stationary

contact

has

.

002

to

.

006

inch

follow

which

is

set

at

the

factory

by

means

of

the

adjusting

screw

.

After

the

adjustment

is

made

the

screw

is

sealed

in

position

with

a

material

which

flows

around

the

threads

and

then

solidifies

.

The

stationary

contact

housing

is

held

in

position

by

a

spring

type

clamp

.

The

spring

adjuster

is

located

on

the

underside

of

the

bridge

and

is

at

-

tached

to

the

moving

contact

arm

by

a

spiral

spr

-

ing

.

The

spring

adjuster

Is

also

held

in

place

by

a

spring

type

clamp

.

When

contacts

close

,

the

electrical

connection

is

made

through

the

stationary

contact

housing

clamp

,

to

the

moving

contact

,

through

the

spiral

spring

and

out

to

the

spring

adjuster

clamp

.

The

shaft

has

removable

top

and

bottom

jewel

bearings

.

The

shaft

rides

between

the

bottom

pin

bearing

and

the

upper

pin

bearing

with

the

cylinder

rotating

in

an

air

gap

formed

by

the

elec

-

4

Courtesy of NationalSwitchgear.com

l

.

L

.

41

-

748

N

v P

0

L C

«

e p

)

=

^

*

vAT

+

X

+

X

+

X

a

)

JA

»

o

zc

-

zC

CONTACT

CLOSES

V

0

P

*

=

VAT

-

R

+

R

-

R

+

R

-

R

+

R

7

ZA

>

ZA

vPOL

(

«

Efr

-

'

)

-

*

(

-

l

.

5

IAZC

)

,

1

-

X

-

X

(

Q

)

WITH

ZC

«

0

(

b

)

WITH

Zc

>

0

(

C

)

WITH

ZC

<

0

b

)

IAHIJI

±

1

£

°

b

.

I

<

IKVAT

CONTACT

CLOSES

Sub

.

2

185

A

182

VOP

VAT

I

1

Fig

.

5

.

R

-

X

Diagram

Characteristics

with

Various

Zc

—

Compensator

Settings

+

l

.

5

IaZA

I

DIRECTIONAL

UNIT

The

directional

unit

is

an

induction

cylinder

unit

operating

on

the

interaction

between

the

polarizing

circuit

flux

and

the

operating

circuit

flux

.

CONTACT

CLOSES

^

K

(

-

I

.

SIAZC

)

vlT

vOP

C

)

I A

=

|

IAILL

9 0

°

I J

H

-

1.5

IAZA

v

POL

(

REF

)

Sub

.

2

185

A

331

Mechanically

,

the

directional

unit

is

composed

of

the

same

basic

components

as

the

distance

unit

:

A

die

-

cast

aluminum

frame

,

an

electromagnet

,

a

moving

element

assembly

,

and

a

molded

bridge

.

The

electromagnet

has

two

series

-

connected

polarizing

coils

mounted

diametrically

opposite

one

another

;

two

series

-

connected

operating

coils

mounted

diametrically

opposite

one

another

;

two

magnetic

adjusting

plugs

;

upper

and

lower

ad

-

justing

plug

clips

,

and

two

locating

pins

.

The

locating

pins

are

used

to

accurately

position

the

lower

pin

bearing

,

which

is

threaded

into

the

bridge

.

The

electromagnet

is

secured

to

the

frame

by

four

mounting

screws

.

Fig

.

6

.

Effect

of

Compensator

Voltages

(

Zc

is

positive

)

holding

the

upper

pin

bearing

,

the

bridge

is

used

for

mounting

the

adjustable

stationary

contact

housing

.

The

stationary

contact

housing

is

held

in

position

by

a

spring

type

clamp

.

The

spring

ad

-

juster

is

located

on

the

underside

of

the

bridge

and

is

attached

to

the

moving

contact

arm

by

a

spiral

spring

.

The

spring

adjuster

is

also

held

in

place

by

a

spring

type

clamp

.

UNDERVOLTAGE

UNIT

The

voltage

unit

is

an

induction

-

cylinder

unit

.

Mechanically

,

the

voltage

unit

is

composed

like

the

directional

unit

,

of

four

components

:

A

diecase

aluminum

frame

,

an

electromagnet

,

a

moving

element

assembly

,

and

a

molded

bridge

.

The

electromagnet

has

two

pairs

of

voltage

coils

.

Each

pair

of

diametrically

opposed

coils

is

connected

in

series

.

In

addition

one

pair

is

in

series

with

an

adjustable

resistor

.

These

sets

are

in

parallel

as

shown

in

Fig

.

3

.

The

adjustable

resistor

serves

not

only

to

shift

the

phase

angle

of

the

one

The

moving

element

assembly

consists

of

a

spiral

spring

,

contact

carrying

member

,

and

an

aluminum

cylinder

assembled

to

a

molded

hub

which

holds

the

shaft

.

The

shaft

has

removable

top

and

bottom

jewel

bearings

.

The

shaft

rides

between

the

bottom

pin

bearing

and

the

upper

pin

bearing

with

the

cylinder

rotating

in

an

air

gap

formed

by

the

electromagnet

and

the

magnetic

core

.

The

bridge

is

secured

to

the

electromagnet

and

frame

by

two

mounting

screws

.

In

addition

to

5

Courtesy of NationalSwitchgear.com

I

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Fig

.

7

.

Typical

Machine

Capacity

Curves

Plotted

on

a

Per

Unit

KVA

Basis

(

183

,

500

KVA

,

45

#

H

2

,

18

KV

,

0.9

pt

,

0.64

SCR

,

inner

-

cooled

,

3600

rpm

.

)

flux

with

respect

to

the

other

to

produce

torque

,

but

it

also

provides

a

pick

-

up

adjustment

.

Otherwise

the

undervoltage

unit

is

similar

in

its

construction

to

the

directional

unit

.

TELEPHONE

RELAY

The

telephone

relay

(

X

)

has

a

slow

drop

-

out

characteristic

.

When

energized

,

the

solenoid

core

attracts

an

iron

right

-

angle

armature

bracket

which

in

turn

opens

the

break

contacts

.

In

actual

service

,

the

relay

is

normally

energized

holding

the

break

contacts

open

.

(

Note

:

the

make

contacts

are

not

used

.

)

Drop

-

out

delay

adjustment

is

obtained

by

varying

the

air

-

gap

between

the

armature

and

the

core

.

INDICATING

CONTACTOR

SWITCH

UNIT

(

ICS

)

Fig

.

8

.

Typical

Machine

Capacity

Curves

and

Sample

KLF

Settings

—

Per

Unit

impedance

The

front

spring

,

in

addition

to

holding

the

target

,

provides

restraint

for

the

armature

and

thus

controls

the

pickup

of

the

switch

.

OPERATION

The

relay

is

connected

and

applied

to

the

system

as

shown

in

Fig

.

4

.

The

directional

unit

closes

its

contacts

for

lagging

var

flow

into

the

machine

.

Its

zero

torque

line

has

been

set

at

—

13

°

from

the

R

-

axis

.

Its

primary

function

is

to

prevent

operation

of

the

relay

during

external

faults

.

The

impedance

unit

closes

its

contacts

when

,

as

a

result

of

reduction

in

excitation

,

the

impedance

of

the

machine

as

viewed

from

its

terminals

is

less

than

a

predetermined

value

.

The

operation

of

both

the

impedance

and

directional

units

sounds

an

alarm

,

and

the

additional

operation

of

the

under

-

voltage

unit

trips

the

machine

.

As

shown

in

Fig

.

4

,

the

contacts

of

all

three

units

are

connected

in

series

across

a

telephone

type

relay

designated

X

,

which

provides

approximately

15

cycles

time

The

dc

indicating

contactor

switch

is

a

small

clapper

-

type

device

.

A

magnetic

armature

,

to

which

leaf

-

spring

mounted

contacts

are

attached

,

is

attracted

to

the

magnetic

core

upon

energiza

-

tion

of

the

switch

.

When

the

switch

closes

,

the

moving

contacts

bridge

two

stationary

contacts

,

completing

the

trip

circuit

.

Also

during

this

opera

-

tion

two

fingers

on

the

armature

deflect

a

spring

located

on

the

front

of

the

switch

,

which

allows

the

operation

indicator

target

to

drop

.

The

target

is

reset

from

the

outside

of

the

case

by

a

push

rod

located

at

the

bottom

of

the

cover

.

6

Courtesy of NationalSwitchgear.com

I

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N

delay

on

dropout

before

energizing

the

trip

coil

.

This

time

delay

is

to

insure

positive

contact

coor

-

dination

under

all

possible

operating

conditions

.

During

normal

conditions

,

all

contacts

are

open

.

position

(

+

ZQ

)

the

circle

includes

the

origin

;

with

the

opposite

link

position

(

—

ZQ

)

the

circle

misses

the

origin

.

The

following

paragraphs

explain

this

compensator

action

.

PRINCIPLE

OF

DISTANCE

UNIT

OPERATION

The

distance

unit

is

an

inducation

cylinder

unit

having

directional

characteristics

.

Operation

depends

on

the

phase

relationship

between

magnetic

fluxes

in

the

poles

of

the

electromagnet

.

Referring

to

Fig

.

4

note

that

Rg

and

Cg

cause

the

polarizing

voltage

to

be

shifted

90

°

in

the

lead

-

ing

direction

.

Thus

,

when

the

current

is

zero

,

polar

-

ing

voltage

VpQL

leads

the

operating

voltage

VQP

by

90

°

,

as

shown

in

Fig

.

6

(

a

)

.

This

relation

produces

restraining

torque

.

To

illustrate

how

Z

\

fixesd

the

long

reach

,

assume

a

relay

current

which

leads

VJN

by

90

°

and

of

sufficient

magnitude

to

operate

the

relay

.

This

means

the

apparent

im

-

pedance

is

along

the

—

X

axis

.

Note

in

Fig

.

6

(

b

)

that

the

Z

/

±

compensation

reverses

the

operating

voltage

phase

position

.

The

relay

balances

when

this

voltage

is

zero

.

Note

that

this

balance

is

un

-

affected

by

the

ZQ

compensation

,

since

this

com

-

pensation

merely

increases

the

size

of

VpQL

-

One

set

of

opposite

poles

,

designated

as

the

operating

poles

are

energized

by

voltage

Vjy

modi

-

fied

by

a

voltage

derived

from

the

long

reach

com

-

pensator

T

^

.

The

other

set

of

poles

(

polarizing

)

are

energized

by

the

same

voltage

Vj

-

p

except

modified

by

a

voltage

derived

from

the

short

reach

compensator

TQ

The

flux

in

the

polarizing

pole

is

so

adjusted

that

the

unit

closes

its

contacts

when

-

ever

flux

in

the

operating

set

of

poles

leads

the

flux

in

the

polarizing

set

.

For

lagging

current

conditions

note

in

Fig

.

6

(

c

)

how

VpQL

is

reversed

by

the

ZQ

compensa

-

tion

.

In

this

case

the

Z

\

compensation

has

no

effect

on

the

balance

point

.

This

explains

why

the

reach

point

is

fixed

independently

by

ZQ

.

The

voltage

Vjy

is

equal

to

V

IT

=

V

12

+

0.5

V

23

=

1.5

V

1

N

(

1

)

As

shown

in

Fig

.

4

,

one

-

half

of

V

23

,

voltage

is

physically

derived

in

the

relay

at

midtap

of

a

re

-

actor

connected

across

voltage

V

23

.

Reach

of

the

distance

unit

is

determined

by

compensators

T

^

and

T

^

as

modified

by

auto

-

transformer

settings

.

Compensators

T

^

and

T

^

are

designed

so

that

its

mutual

impedance

Z

\

or

ZQ

has

under

CHARACTERISTICS

and

SET

-

TINGS

.

The

mutual

impedance

of

a

compensator

is

defined

here

as

the

ratio

of

secondary

induced

voltage

to

primary

current

and

is

equal

to

T

.

Each

secondary

compensator

voltage

is

in

series

with

the

voltage

Vjy

.

Compensator

voltages

is

in

series

with

the

voltage

V

jp

.

Compensator

voltages

are

equal

to

1.5

Ij

Z

\

for

long

reach

compensator

and

1.5

11

ZQ

for

short

reach

compensator

,

where

I

,

is

the

relay

current

.

Fig

.

5

shows

how

the

compensation

voltages

1.5

11

Z

\

and

1.5

I

j

ZQ

influence

the

R

-

X

circle

.

Note

that

Z

\

independently

determines

the

“

long

reach

”

,

while

ZQ

independently

fixes

the

“

short

reach

”

.

With

the

reversing

links

in

the

normal

Fig

.

6

assumes

that

ZQ

is

positive

(

circle

in

-

cludes

origin

)

.

If

the

current

coil

link

is

reversed

,

the

compensation

becomes

+

1.51

,

ZQ

.

In

Fig

.

6

(

b

)

this

change

would

result

in

,

VpQL

being

reduced

rather

increased

by

the

compensation

.

As

the

current

increases

VpQL

will

finally

be

reversed

,

reestablishing

restraining

torque

.

Thus

,

the

current

need

not

reverse

in

order

to

obtain

a

“

short

reach

”

balance

point

.

Instead

the

apparent

impedance

need

only

move

towards

the

origin

in

the

-

X

region

to

find

the

balance

point

.

Therefore

,

the

circle

does

not

include

the

origin

with

a

reversed

link

position

.

CHARACTERISTICS

The

type

KLF

relay

is

available

in

one

range

.

DISTANCE

UNIT

The

distance

unit

can

be

set

to

have

characteristic

circles

that

pass

through

origin

,

in

-

clude

it

,

or

exclude

it

,

as

shown

in

Fig

.

5

.

7

Courtesy of NationalSwitchgear.com

I

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L

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748

N

To

change

taps

requires

connecting

the

lead

located

in

front

of

the

tap

block

to

the

desired

set

-

ting

by

means

of

a

screw

connection

.

TRIP

CIRCUIT

CONSTANT

Indicating

Contactor

Switch

(

ICS

)

0.2

ampere

tap

-

6.5

ohm

dc

resistance

2.0

ampere

tap

-

0.15

ohm

dc

resistance

The

ZA

and

ZQ

values

are

deternrned

by

com

-

pensator

settings

and

modified

by

autotransformer

settings

S

,

L

,

and

R

.

The

impedance

settings

in

ohms

reach

can

be

made

for

any

value

from

2.08

to

56

ohms

for

ZA

,

and

from

0.79

ohm

to

18

ohms

for

ZQ

in

steps

of

3

percent

.

The

taps

are

marked

as

follows

:

BURDEN

TA

Current

at

5

Amps

2.4

,

3.16

,

4.35

,

5.93

,

8.3

,

11.5

,

15.8

TA

&

TC

Settings

VA

Angle

of

Lag

60

Hz

50

Hz

60

Hz

50

Hz

TC

0.0

,

0.91

,

1.27

,

1.82

,

2.55

,

3.64

,

5.1

77

°

74

°

18.6

Max

.

Min

.

15.7

51

°

46

°

3.4

3.8

(

SA

.

sC

)

Potential

at

120

Volts

Phase

AB

1

,

2

,

3

,

(

MA

,

MC

)

VA

Angle

of

Lag

60

Hz

50

Hz

+

values

between

taps

.

03

,

.

06

,

.

06

SA

=

sc

60

Hz

50

Hz

2

°

2

°

1

18.0

18.0

DIRECTIONAL

UNIT

The

KLF

relay

is

designed

for

potential

polarization

with

an

internal

phase

shifter

,

so

that

maximum

torque

occurs

when

the

operating

current

leads

the

polarizing

voltage

by

ap

-

proximately

13

degrees

.

The

minimum

pickup

has

been

set

by

the

spring

tension

to

be

approximately

1

volt

and

5

amperes

at

maximum

torque

angle

.

31

°

26

°

2

14.4

13.8

39

°

34

°

3

13.9

13.0

Phase

BC

VA

Angle

of

Lag

60

Hz

50

Hz

SA

=

SC

60

Hz

50

Hz

12

°

10

°

1

2.6

2.6

38

°

33

°

2

5.9

5.5

42

°

37

°

3

6.6

6.1

UNDERVOLTAGE

UNIT

The

undervoltage

unit

is

designed

to

close

its

contacts

when

the

voltage

is

lower

than

the

set

value

.

The

undervoltage

unit

is

energized

with

Vjj

-

voltage

.

This

voltage

is

equal

to

1.5

V

^

q

voltage

.

The

contacts

can

be

adjusted

to

close

over

the

range

of

65

to

85

percent

of

normal

system

voltage

.

The

dropout

ratio

of

the

unit

is

98

percent

or

higher

.

D

-

C

Circuit

Watts

+

Rated

Rating

125

3.9

250

7.8

THERMAL

RATINGS

Potential

:

132

volts

(

L

-

L

)

continuous

Current

:

8

amperes

continuous

200

amperes

for

1

second

TRIP

CIRCUIT

The

main

contacts

will

safely

close

30

amperes

at

250

volts

dc

and

the

seal

-

in

contacts

of

the

in

-

dicating

contactor

switch

will

safely

carry

this

current

long

enough

to

trip

a

circuit

breaker

.

SETTING

CALCULATIONS

GENERAL

SETTING

RECOMMENDATIONS

The

KLF

relay

may

be

applied

as

a

single

-

zone

device

,

or

two

relays

may

be

used

to

provide

two

-

zone

protection

.

The

single

-

zone

setting

may

be

fully

offset

(

Zone

-

1

)

or

may

include

the

origin

The

indicating

contactor

switch

has

two

taps

that

provide

a

pick

-

up

setting

of

0.2

or

2

amperes

.

8

Courtesy of NationalSwitchgear.com

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L

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N

TABLEI

RECOMMENDED

SETTINGS

FOR

KLF

RELAY

ZONE

1

(

ALONE

)

ZONE

2

(

ALONE

)

BOTH

ZONE

1

&

ZONE

2

See

Fig

.

10

IMPEDANCE

SETTING

See

Fig

.

11

See

Figs

.

10

&

11

VOLTAGE

SETTING

(

a

)

Contact

shorted

or

(

b

)

Set

at

80

%

for

security

80

%

Zone

1

voltage

contact

shorted

with

Zone

2

set

at

80

%

TD

-

1

Zone

1

timer

=

VA

sec

Zone

2

timer

=

1

sec

VA

to

1

sec

(

1

sec

preferred

)

VA

to

1

sec

(

1

sec

preferred

)

Not

required

for

(

a

)

above

.

For

(

b

)

above

use

1

min

.

TD

-

2

1

min

.

1

min

.

Less

sensitive

to

stable

system

swings

ADVANTAGES

1

)

More

sensitive

to

LOF

condition

2

)

Can

operate

on

partial

LOF

3

)

Provide

alarm

features

for

manual

operation

(

1

)

Same

as

(

1

)

,

(

2

)

and

(

3

)

at

left

.

(

2

)

Provides

back

-

up

protection

TABLE

II

SPECIAL

SETTINGS

FOR

MULTI

MACHINES

BUSSED

AT

MACHINE

TERMINALS

ZONE

1

(

ALONE

)

ZONE

2

(

ALONE

)

BOTH

ZONE

1

&

ZONE

2

See

Fig

.

10

IMPEDANCE

SETTING

See

Fig

.

11

See

Figs

.

10

&

11

VOLTAGE

SETTING

(

a

)

Contact

shorted

or

(

b

)

set

at

87

%

for

security

87

%

Zone

l

voltage

contact

shorted

with

Zone

2

set

at

87

%

TD

-

l

Zone

l

timer

=

VA

sec

Zone

2

timer

=

l

sec

VA

to

1

sec

(

1

sec

preferred

)

VA

to

1

sec

(

1

sec

preferred

)

TD

-

2

Not

required

for

(

a

)

above

(

a

)

above

.

For

(

b

)

above

use

10

sec

for

cond

.

cooled

,

25

sec

for

conv

.

cooled

10

sec

for

cond

.

cooled

.

25

sec

for

conv

.

cooled

.

10

sec

for

cond

.

cooled

25

sec

for

conv

.

cooled

9

Courtesy of NationalSwitchgear.com

I

.

L

.

41

-

748

N

Converting

to

the

impedance

curve

:

lvt

2

|

=

102

(

KVA

)

c

0.715

=

1.4

per

unit

(

Zone

-

2

)

.

The

two

-

zone

application

would

require

a

zone

-

1

KLF

and

a

zone

-

2

KLF

,

approximately

equivalent

to

two

-

zone

step

-

distance

line

protec

-

tion

.

A

generalized

external

schematic

,

which

is

applicable

to

either

Zone

-

1

or

Zone

-

2

relays

is

shown

in

Fig

.

9

.

The

recommended

settings

and

relative

advantages

of

these

various

con

-

figurations

are

summarized

in

Table

I

.

!

z

|

=

Since

the

angle

remains

the

same

,

the

im

-

pedance

plot

conversion

is

:

Z

=

1.4

/

—

33.6

°

,

as

shown

in

Fig

.

8

.

The

single

-

zone

and

two

-

zone

setting

recommendations

are

modified

when

two

or

more

machines

are

bussed

at

the

machine

terminals

.

The

voltage

and

time

delay

considerations

are

treated

in

detail

in

other

sections

of

this

leaflet

.

The

recommended

settings

are

outlined

in

Table

After

plotting

the

steady

-

state

stability

limit

and

the

machine

capability

curves

on

the

R

-

X

dia

-

gram

,

plot

the

relay

circle

between

the

stability

limit

and

the

capability

curve

.

(

Note

in

Fig

.

8

that

the

relay

circle

cannot

be

plotted

within

the

60

#

—

Vj

=

0.95

curve

,

since

the

machine

is

beyond

the

steady

-

state

stability

limit

for

these

conditions

.

)

This

plot

defines

the

desired

reach

Z

\

and

radius

R

of

the

relay

circle

.

Then

use

the

following

pro

-

cedure

to

select

tap

settings

.

1000

(

kv

)

2

Rc

II

.

ZONE

-

2

SETTING

CALCULATIONS

(

DISTANCE

UNIT

)

Set

the

distance

unit

to

operate

before

the

steady

-

state

stability

limit

is

exceeded

.

Also

,

to

allow

maximum

output

without

an

alarm

,

set

the

distance

unit

to

allow

the

machine

to

operate

at

maximum

hydrogen

pressure

and

0.95

per

unit

voltage

(

lowest

voltage

for

which

the

capability

curve

machine

cannot

be

realized

without

ex

-

ceeding

the

steady

-

state

stability

limit

,

set

the

dis

-

tance

unit

to

operate

before

the

steady

-

state

limit

is

exceeded

.

Capability

curves

similar

to

Fig

.

7

are

obtained

from

the

generator

manufacturer

.

(

2

)

ohms

zbase

-

(

kva

)

Ry

where

Zbase

=

one

Per

un

^

primary

ohms

/

as

seen

from

the

relay

kv

=

rated

phase

-

to

-

phase

voltage

of

the

machine

.

kva

=

rated

kva

of

the

machine

Rc

=

the

current

transformer

ratio

.

Rv

=

the

potential

transformer

ratio

.

To

determine

the

desired

setting

convert

the

capability

curve

of

Fig

.

7

of

the

impedance

curve

VT

2

|

(

KVA

)

C

per

wire

terminal

voltage

and

(

KVA

)

c

is

the

per

unit

output

.

The

angle

of

each

point

on

the

im

-

pedance

curve

is

the

same

angle

as

the

corres

-

ponding

point

on

the

capability

curve

.

of

Fig

.

8

by

calculating

-

,

where

Vj

is

the

The

actual

settings

,

and

ZQ

,

are

:

ZA

=

(

ZA

Per

unit

)

x

(

zbase

)

(

3

)

ZC

=

(

zc

Per

unit

)

x

(

zbase

)

=

(

4

)

(

2

R

—

Z

^

)

x

(

Zbase

)

For

example

,

from

Fig

.

7

,

an

output

of

0.6

per

unit

KW

on

30

#

hydrogen

pressure

curve

is

—

0.4

per

unit

reactive

KVA

.

Therefore

,

Where

R

=

radius

of

circle

in

per

unit

.

The

tap

-

plate

settings

are

made

accord

-

ing

to

equations

:

(

KVA

)

c

=

V

(

0

-

6

)

2

+

(

_

o

.

4

)

2

=

0.715

per

unit

and

,

9

=

Tan

—

1

(

TS

(

5

)

-

0.4

ZA

(

°

r

ZC

)

=

)

=

-

33.6

°

1

+

M

0.6

10

Courtesy of NationalSwitchgear.com