Generator Protection Class presentation

7/28/2019 Generator Protection Class presentation

1/123

Completed by :Mohammad Ibnul Hossain

Executive Engineer (Operation)Tongi 80(105) MW GT Power Station

Bangladesh Power Development BoardE-mail : [email protected]

GENERATOR PROTECTION


2/123


3/123


4/123

Possible Faults


5/123

Abnormal operating condition

overcurrent / overload unbalanced load

over temperature over- and undervoltage over- and underexcitation

over- and underfrequency

over-fluxing

asynchronous running

out of step

generator motoring failures in the machine control system (i.e. AVR orgovernor failure)

failures in the machine cooling system


6/123

In abnormal condition ,

those dont need immediate trip the unit generator

Or transformer but cant continue , at some stage

we must trip-out the system.


7/123

Different Power Plant Electrical Layout


8/123

Damage to the stator core in case of earth-fault

The stator cant withstand with a small amount of ground current evenWith short period of time.

Arrangement must be taken to limit the ground fault current not more

than 10 amp.


9/123

How it is done ?

it is achieved by grounding

Here we see different types of alternatives.

Solidly grounded through a resistor typically in Europe

Grounding transformer , typically for U.S

Stator winding Earthing Practice :


10/123

87 Differential59 over -voltages

24V/HZ over fluxing

49S stator Over load

51 over -current

64s Ground Fault stator

Inter-turn

64R Ground fault Rotor

71 pole slipping

40 Loss of excitation

32 Reverse Power81 O/U Frequency

Turbine

Rotor Stator

Allocation of Protection Function

46 Negative Phase Sequence


11/123

No.DESCRIPTION

2Time-delay relay

21

Distance relay24

Over excitation / Volts per Hertz

25 Synchronism-check relay

27 Under voltage relay

27TN Third-Harmonic Under voltage relay

30 Annunciator device

32 Reverse power relay

37 Undercurrent or underpower relay

40 Field excitation relay

46 Negative sequence overcurrent relay


12/123

47 Negative sequence overvoltage relay

49 Thermal relay

50 instantaneous AC overcurrent relay

50DT Split Phase Differential

50/27 inadvertent Energizing

50BF Breaker Failure

51 AC Inverse Time Overcurrent relay

52 Circuit breaker


13/123

59Overvoltage relay

59DThird-Harmonic Voltage Differential Ratio

60 Voltage balance or loss of potential relay

63 Pressure device

64F Field Ground relay

64B Brush Lift-Off Detection

64S100% Stator Ground Protection by LowFrequency Injection

67 AC directional overcurrent relay

68 Power Swing Blocking

69Permissive relay

59N Single Phase Overvoltage Relay


14/123

74 Alarm relay

76 DC overcurrent relay

78 Out-of-step relay

79 AC reclosing relay

81 Frequency relay

81R Rate of Change Frequency relay

83 Transfer device

85 Carrier or pilot-wire relay

86 Lock out relay

87 Differential relay

94 Auxiliary tripping relay


15/123

Consequence of stator short circuit

Insulation. windings and stator core can be

damaged

Large forces, caused by large fault currents. can

give damage to other components in the plant

Risk of explosion and fire

Mechanical stress on generator- and turbine

shafts

Stator Short Circuit


16/123

Detection of stator short circuits

Protection functions Generator differential protection

Unit differential protection Directional negative sequence overcurrent

protection

Under impedance protection

Phase overcurrent protection Voltage dependent phase overcurrent protection Under voltage protection

Phase overcurrent protection of the unit

transformer


17/123

Phase to phase fault in the stator winding

Endangering condition

Overcurrent Protected object

Stator winding

Consequences Heating Forces

Smelted stator core


18/123

Y

G

87 N

Diff.rel.50BFBrk.flr.

50/51

OC49

Therm.

87Oo/a Diff

51

OC

50/51

OC

YY

YY

51OC

60

FL81

Freq.rel.

50

Ac.Eneg

GENERATOR AND UNIT TRANS FORMER UNIT SCHEME

51/67

OC(Idm/dir.)

50

Neg.Pha.

87G

Gen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S

100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37

Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.

64S

100%GFP+ REX0061

UnitX

for.

46

Neg.Pha.


19/123

Y

G

87 N


50/51

OC49

Therm.

87ODiff(x-f)

51

OC

50/51

OC

YY

YY

51OC

60

FL81

Freq.rel.

50

Ac.Eneg


51/67

OC(Idm/dir.)

50

Neg.Pha.

87G

Gen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S

100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Distance

32

Rev. Pow.

37

Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.

64S

100%GFP+ REX0061

UnitX

for.

87Oo/a Diff

Udr.Imp.pro.

46

Neg.Pha.


20/123

Y

G

87 N


50/51

OC49

Therm.

87ODiff(x-f)

51

OC

50/51

OC

YY

YY

51OC

60

FL81

Freq.rel.

50

Ac.Eneg


51/67

OC(Idm/dir.)

50

Neg.Pha.

87GGen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S

100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Distance

32

Rev. Pow.

37

Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.

64S

100%GFP+ REX0061

UnitX

for.

87Oo/a Diff

Udr.Imp.pro.

46

Neg.Pha.


21/123

Y

G

87 N


50/51

OC49

Therm.

87ODiff(x-f)

51

OC

50/51

OC

YY

YY

51OC

60

FL81

Freq.rel.

50

Ac.Eneg


51/67

OC(Idm/dir.)

50

Neg.Pha.

87GGen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S

100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Distance

32

Rev. Pow.

37

Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.

64S

100%GFP+ REX0061

UnitX

for.

87Oo/a Diff

Udr.Imp.pro.

46

Neg.Pha.


22/123

Y

G

87 N


50/51

OC49

Therm.

87ODiff(x-f)

51

OC

50/51

OC

YY

YY

51OC

60

FL81

Freq.rel.

50

Ac.Eneg


51/67

OC(Idm/dir.)

50

Neg.Pha.

87GGen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S

100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Distance

32

Rev. Pow.

37

Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.

64S

100%GFP+ REX0061

UnitX

for.

87Oo/a Diff

Udr.Imp.pro.

46

Neg.Pha.

Diff ti l P t ti


23/123

Let us , Consider , X protected EquipmentCT1 and CT2 same transformation ratioThe current flow in the primary and secondary sides of power

transformer are identical, assuming ideal transformer.The secondary current i1 and i2 are equal in magnitude and oppositein direction.So, the net current in the differential coil is zero at load condition

(without fault), and the relay will not operate .

Differential Protection

XI1 I2

i1i2

TC

i1

i2

i1 i2

Diff. Relay

CT1 CT2


24/123


XI1 I2

i1

i2

TC

i1

i2

i1 i2

Diff. Relay

CT1 CT2

External Fault happens ,

Then , I1 and I2 increases as well as i1 and i2 increasesBut the phase angle of i1 and i2 will be the same ,

So , the net current in the TC or Operating Coil = 0

So, the relay will not operate


25/123

XI1 I2

i1

i2

TC

i1

i2

i1 i2

Diff. Relay

CT1 CT2


is another source to feed the fault ,

So I2 0 ,

I diff = i1 + i2 which is very highAnd trips the Differential Relay


26/123

Biased differential relay

XI1 I2

i1

i2

Op

i1

i2

i1 i2

Biased Diff. Relay

CT1 CT2

Res. Res.

Large external fault cause false operation

To make more stable Two Restraining ( Biasing ) coilAndOne Operating coil is introduced .What is the function of two Restraining ( Biasing ) Coils ?Restraining coils will oppose the operation of operating coil.

The relay will operate only when the operating force > the restraining force


27/123

Tripping Characteristics of Simple Differential Relay


28/123

Tripping Characteristics of Biased Differential Relay with TwoStages (Two Slops )


29/123

Connections of CTs for differential protection of generator.

Percentage differential relaying of a star connected generator , for phase-phase faults.


30/123

Percentage differential relay of a delta connected generator ,forphase-phase fault.

G diff i l i O h h


31/123

Generator differential protection Operates then what

happens ?

Shall trip the followings :

Turbine: close down active power

Generator breaker: if available

Field breaker

Unit breaker: If no generator breaker Fire protection

Differential Protection can be used :


32/123

Differential Protection can be used :

The layout of what we are talking about 87G the differentialprotection of gen87T- the differential protection of step-uptransformer870- both the generator and the step-up transformer.


33/123


34/123

Endangering condition Overcurrent

Protected object

Transformer windings

Consequences

Heating

Forces

Smelted transformer core

Phase to phase fault in the transformer winding

h h f l h f d


35/123

Y

G

87 N


50/51

OC49

Therm.

87Oo/a Diff

51OC

50/51

OC

YY

YY

51OC

60

FL81

Freq.rel.

50

Ac.Eneg


51/67

OC(Idm/dir.)

50

Neg.Pha.

87GGen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37

Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP

+ REX0061

UnitX

for.

46

Neg.Pha.

Ph h f l i h f i di


36/123

Y

G

87 N


50/51

OC49

Therm.

87Oo/a Diff

51OC

50/51

OC

YY

YY

51OC

60

FL81

Freq.rel.

50

Ac.Eneg


51/67

OC(Idm/dir.)

50

Neg.Pha.

87GGen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37

Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP

+ REX0061

UnitX

for.

46

Neg.Pha.

Ph h f l i h f i di


37/123

Y

G

87 N


50/51

OC49

Therm.

87Oo/a Diff

51OC

50/51

OC

YY

YY

51OC

60

FL81

Freq.rel.

50

Ac.Eneg


51/67

OC(Idm/dir.)

50

Neg.Pha.

87GGen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP

+ REX0061

UnitX

for.

46

Neg.Pha.

Ph t h f lt i th t f i di


38/123

Y

G

87 N


50/51

OC49

Therm.

87Oo/a Diff

51OC

50/51

OC

YY

YY

51OC

60

FL81

Freq.rel.

50

Ac.Eneg


51/67

OC(Idm/dir.)

50

Neg.Pha.

87GGen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP

+ REX0061

UnitX

for.

46

Neg.Pha.

fault impedance < load impedance


39/123

fault impedance < load impedanceSo , the fault current > load current.If a short circuit occursthe circuit impedancetherefore a fault is accompanied by large current

Overcurrent relays sense fault currents and also over-loadcurrents.Overcurrent protection is that protection in which the relay picksup when the magnitude of current exceeds the pickup level.The basic element in overcurrent protection is an overcurrent relay.

The overcurrent relays are connected to the system, normally bymeans of CTs. Overcurrent

relaying has following types :- High speed overcurrent protection.- Definite time overcurrent protection.- Inverse minimum time overcurrent protection.

- Directional overcurrent protection (or above any type)

Over-current protection includes the protection from


40/123

Over current protection includes the protection from

overloads .

Overloading of a machine or equipment means the machineis taking Current > rated current .

Hence with overloading , there is an associated temperature

rise .

Overcurrent protection of overloads is generally provided by

thermal relay.

The permissible rise has limit based on insulation class and

material problems.

Over-current protection includes short-circuit protection


41/123

Over current protection includes short circuit protection.

Short circuits can bephase faults

earth faultswinding faults.

Short-circuit currents are generally several times (5 to 20) full

load current.

Fast fault clearance is always desirable on short-circuits

When a machine is protected by differential protection, theover-current is provided in addition as a back-up and in somecases to protect the machine from sustained through fault.

Several protective devices are used for over-current


42/123

Several protective devices are used for over current

protection .

These includes

-Fuses

-Miniature circuit-breakers, molded-case circuit-breakers.

-Circuit-breakers fitted with overloaded coils or tripped byover-current relays.

-Series connected trip coils operating switching devices.

- Over-current relays in conjunction with current

transformers.

Th i i t f t t ti


43/123

The primary requirements of over-current protection are :

The protection should not operate starting currents

permissible overcurrentCurrent surges.

To achieve this

The time delay is provided (in case of inverse relays)If time delay cannot be permitted

high-set instantaneous relaying is used.

- The protection should be co-ordinated with neighbouringover-current protections

CHARACTERISTICS OF RELAY UNITS FOR OVER-CURRENT


44/123

PROTECTION

There is a wide variety of relay-units. These are classified

according to their type and characteristics.

The major characteristic include :

- Definite characteristic

- Extremely Inverse

-Inverse- Inverse characteristic

- Very Inverse

Inverse characteristic


45/123

Inverse characteristic

t 1 / Iwhere I= Current in relay coil

t = Relay limeK = Constant

Very Inverse characteristic

t 1 / Inwhere n = 2 to 8 , according to the requirements.

Connection Scheme withThree Over current Relays


46/123

. Connection Scheme withThree Over-currentRelays

Relay Coil

OvercurrentRelayCB

R Y B

IR IY IB +

AUXILLARYSWITCH

TripCoil

RelayContact

Connection Scheme withThree Over-currentRelays


47/123

Relay Coil

OvercurrentRelay

CB

R YB

IR IY IB

+

AUXILLARYSWITCH

TripCoil

RelayContact

+ DEFINITETIMERELAY

AUXILLARYRELAY

ywith addition of a common time-delay relayand an auxiliary relay

Stator earth fault


48/123

Stator earth fault

Damages on the stator iron

Increased voltage on healthy phases

Small fault currents

Sensitivity requirements on fault clearance

The fault resistance is normally low atstator earth fault

RESTRICTED EARTH-FAULT PROTECTION BY DIFFERENTIAL SYSTEM


49/123

RESTRICTED EARTH FAULT PROTECTION BY DIFFERENTIAL SYSTEM

, Neutral is earthed through resistance to limit earth-fault currents.

With resistance earthing, it is not possible to protect complete winding from earth-fault andthe % of winding protected depends on the value of neutral earthing resistor and the relaysettingSetting Criteria :

The current rating of resistor, resistance value, relay setting, etc. should be selectedcarefully.Setting should be such that the protection does not operate for earth-faults on EHV

side

RESTRICTED EARTH-FAULT PROTECTION BY DIFFERENTIAL SYSTEM (Cont.) a


50/123

RESTRICTED EARTH FAULT PROTECTION BY DIFFERENTIAL SYSTEM (Cont.) a

Setting Criteria (Cont.) :

Earth faults are not likely to occur near the neutral point due to less voltage w.r.t. earth.It is a usual practice to protect about 80 to 85% of generator winding against earth-faults.

It is a usual practice to protect about 80 to 85% of generator winding against earth-faults.

The remaining 20 to 5% winding from neutral side left unprotected by the differentialprotection.

In additional to differential protection, a separate earth-fault protection is provided to take

care of the complete winding against earth faults.

RESTRICTED EARTH-FAULT PROTECTION BY DIFFERENTIAL SYSTEM (Cont.) a


51/123

( )

During earth-fault the current, Ifflows through a part of the generator winding and

neutral to ground circuit.

The corresponding secondary current Is flows through the operating coil andrestricted earth-fault coil of the differential protection.

The setting of the restricted earth fault relay can be selected independent of the

setting of the overcurrent relay.

RESTRICTED EARTH-FAULT PROTECTION BY DIFFERENTIAL SYSTEM (Cont.)


52/123

( )

Here, fault at pointf , Iffault current , VafVoltage

If fault is nearer to neutral point Vafis relatively less .Hence , If is reduced .Not practicable for too sensitive setting , because it will operate in through fault of smallMagnitude for inaccurate CT and saturation of CT.

Practice to provide 85% protection , the rest 15% is protected by another scheme.

Discuss Next.

100% STATOR EARTH-FAULT PROTECTION


53/123

100% STATOR EARTH FAULT PROTECTION

Coupling TransformerGround Circuit

Signal (12.5Hz) continuously injected Stator winding

No Fault Signal feed into stray capacitance .

IN FaultCapacitance is by-passed and monitoring

Current (of 12.5 Hz) is sensed by the measuring system.

Earth Fault in Stator Winding


54/123


Overvoltage in two healthy phases Voltage in the star point Relatively small earth fault current

Protected object Stator winding

Consequences Damage to the stator core Risk of second earth fault

Earth Fault in Stator Winding

Stator Earth Fault Protection


55/123

Y

G

87 N


50/51

OC49

Therm.

87Oo/a Diff51OC

50/51

OC

Y

Y

YY

51

OC

60

FL81

Freq.rel.

50

Ac.Eneg


51/67

OC(Idm/dir.)

50

Neg.Pha.

87GGen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP + REX0061

UnitX

for.

46

Neg.Pha.



56/123

Y

G

87 N


50/51

OC49

Therm.

87Oo/a Diff51OC

50/51

OC

Y

Y

YY

51

OC

60

FL81

Freq.rel.

50

Ac.Eneg


51/67

OC(Idm/dir.)

50

Neg.Pha.

87GGen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP + REX0061

UnitX

for.



57/123

Y

G

87 N


50/51

OC49

Therm.

87Oo/a Diff51OC

50/51

OC

Y

Y

YY

51

OC

60

FL81

Freq.rel.

50

Ac.Eneg


51/67

OC(Idm/dir.)

50

Neg.Pha.

87GGen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP + REX0061

UnitX

for.

46

Neg.Pha.

Stator Earth Fault Close to star point


58/123

Y

G

87 N


50/51

OC49

Therm.

87Oo/a Diff51OC

50/51

OC

Y

Y

YY

51

OC

60

FL81

Freq.rel.

50

Ac.Eneg

Stator Earth Fault Close to star point

51/67

OC(Idm/dir.)

50

Neg.Pha.

87GGen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP + REX0061

UnitX

for.

46

Neg.Pha.

StatorEarth Fault Close to star point


59/123

Y

G

87 N


50/51

OC49

Therm.

87Oo/a Diff51OC

50/51

OC

Y

Y

YY

51

OC

60

FL81

Freq.rel.

50

Ac.Eneg

Stato a t ault Close to sta po t

51/67

OC(Idm/dir.)

50

Neg.Pha.

87GGen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP + REX0061

UnitX

for.

46

Neg.Pha.

Earth fault in transformer HV winding


60/123

f f g


Overcurrent

Protected object

Transformer windings

Consequences Heating

Forces

Smelted transformer core



61/123

Y

G

87 N


50/51

OC49

Therm.

87Oo/a Diff51OC

50/51

OC

Y

Y

YY

51

OC

60

FL81

Freq.rel.

50

Ac.Eneg

f f g

51/67

OC(Idm/dir.)

50

Neg.Pha.

87GGen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP + REX0061

UnitX

for.

46

Neg.Pha.



62/123

Y

G

87 N


50/51

OC49

Therm.

87Oo/a Diff51OC

50/51

OC

Y

Y

YY

51

OC

60

FL81

Freq.rel.

50

Ac.Eneg

f f g

51/67

OC(Idm/dir.)

50

Neg.Pha.

87GGen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP + REX0061

UnitX

for.

46

Neg.Pha.



63/123

Y

G

87 N


50/51

OC49

Therm.

87Oo/a Diff51OC

50/51

OC

Y

Y

YY

51

OC

60

FL81

Freq.rel.

50

Ac.Eneg

f f g

51/67

OC(Idm/dir.)

50

Neg.Pha.

87GGen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP + REX0061

UnitX

for.

StatorEarth Fault Protection


64/123

Y

G

87 N


50/51

OC49

Therm.

87Oo/a Diff51OC

50/51

OC

Y

Y

YY

51

OC

60

FL81

Freq.rel.

50

Ac.Eneg51/67

OC(Idm/dir.)

50

Neg.Pha.

87GGen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP + REX0061

UnitX

for.

46

Neg.Pha.

Stator Earth fault in transformer HV winding


65/123

Y

G

87 N


50/51

OC49

Therm.

87Oo/a Diff51OC

50/51

OC

Y

Y

YY

51

OC

60

FL81

Freq.rel.

50

Ac.Eneg

f f g

51/67

OC(Idm/dir.)

50

Neg.Pha.

87GGen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP + REX0061

UnitX

for.

46

Neg.Pha.



66/123

Y

G

87 N


50/51

OC49

Therm.

87Oo/a Diff51OC

50/51

OC

Y

Y

YY

51

OC

60

FL81

Freq.rel.

50

Ac.Eneg

f f g

51/67

OC(Idm/dir.)

50

Neg.Pha.

87GGen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP + REX0061

UnitX

for.

46

Neg.Pha.

Earth fault in transformer LV winding


67/123

Endangering condition Overvoltage in two healthy phases

Voltage in the star point Relatively small earth fault current

Protected object

Transformer winding

Consequences

Small possibility to damage transformer

core Risk of second earth fault

Earth-Fault in the LV Winding


68/123

Y

G

87 N


50/51

OC49

Therm.

87Oo/a Diff51OC

50/51

OC

Y

Y

YY

51

OC

60

FL81

Freq.rel.

50

Ac.Eneg51/67

OC(Idm/dir.)

50

Neg.Pha.

87GGen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP + REX0061

UnitX

for.



69/123

Y

G

87 N


50/51

OC49

Therm.

87Oo/a Diff51OC

50/51

OC

Y

Y

YY

51

OC

60

FL81

Freq.rel.

50

Ac.Eneg51/67

OC(Idm/dir.)

50

Neg.Pha.

87GGen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP + REX0061

UnitX

for.



70/123

Y

G

87 N


50/51

OC49

Therm.

87Oo/a Diff51OC

50/51

OC

Y

Y

YY

51

OC

60

FL81

Freq.rel.

50

Ac.Eneg51/67

OC(Idm/dir.)

50

Neg.Pha.

87GGen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP + REX0061

UnitX

for.

Turn to turn turn fault in the stator winding :


71/123



72/123

Y

G

87 N


50/51

OC49

Therm.

87Oo/a Diff51OC

50/51

OC

Y

Y

YY

59N

OV

60

FL81

Freq.rel.

50

Ac.Eneg51/67

OC(Idm/dir.)

50

Neg.Pha.

87GGen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP + REX0061

UnitX

for.



73/123

Y

G

87 N


50/51

OC49

Therm.

87Oo/a Diff51OC

50/51

OC

Y

Y

YY

59N

OV

60

FL81

Freq.rel.

50

Ac.Eneg51/67

OC(Idm/dir.)

50

Neg.Pha.

87GGen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP + REX0061

UnitX

for.

51N detected the fault whenIt developes



74/123

Y

G

87 N


50/51

OC49

Therm.

87Oo/a Diff51OC

50/51

OC

Y

Y

YY

59N

OV

60

FL81

Freq.rel.

50

Ac.Eneg51/67

OC(Idm/dir.)

50

Neg.Pha.

87GGen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP + REX0061

UnitX

for.

51N detected the fault whenIt developes

Rotor Earth Fault :


75/123

The field circuit of the generator is normally isolated

from earth

With a single earth fault in the rotor circuit it is possible

to have continuous operation without generator

damages

There is however a risk of a second rotor earth fault. In

such a case there will be large current and risk of severedamages.

The requirement of fast fault clearance is moderate


76/123

Earth-Fault in Rotor Winding :


77/123


None

Protected object

Rotor windingConsequences

Risk of evolving into double earth fault

g

Earth-Fault in the Rotor


78/123

Y

G

87 N


50/51

OC49

Therm.

87Oo/a Diff51OC

50/51

OC

Y

Y

YY

59N

OV

60

FL81

Freq.rel.

50

Ac.Eneg51/67

OC(Idm/dir.)

50

Neg.Pha.

87GGen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP + REX0061

UnitX

for.



79/123

Y

G

87 N


50/51

OC49

Therm.

87Oo/a Diff51OC

50/51

OC

Y

Y

YY

59N

OV

60

FL81

Freq.rel.

50

Ac.Eneg51/67

OC(Idm/dir.)

50

Neg.Pha.

87GGen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP + REX0061

UnitX

for.


80/123

Loss of/Under excitation


81/123


Stator reactive current component

Protected object Rotor and stator winding

Consequences

Thermal damage of rotor and statorend regions

Asynchronous machine operation

Voltage and current variations



82/123

Y

G

87 N


50/51

OC49

Therm.

87Oo/a Diff51OC

50/51

OC

Y

Y

YY

59N

OV

60

FL81

Freq.rel.

50

Ac.Eneg51/67

OC(Idm/dir.)

50

Neg.Pha.

87GGen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP + REX0061

UnitX

for.



83/123

Y

G

87 N


50/51

OC49

Therm.

87Oo/a Diff51OC

50/51

OC

YY

YY

59N

OV

60

FL81

Freq.rel.

50

Ac.Eneg51/67

OC(Idm/dir.)

50

Neg.Pha.

87GGen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP + REX0061

UnitX

for.

Generator motoring protection


84/123

Generator shall produce active power (i.e. P>0)

When it starts to receive the active power it acts as a

motor (i.e. P


85/123

loss of prime-mover

low water flow (hydro) load variations I problems

Effects

steam units overheating of turbine and turbine blade

hydro units cavitations of the blades

Reverse Power Protection


86/123


Motor operation

Protected object

Turbine

Consequences Excessive heating of turbine blades (steam units)

Mechanical damages to thrust bearing (Francisturbines) Explosion risk for diesel units



87/123

Y

G

87 N


50/51

OC49

Therm.

87Oo/a Diff51OC

50/51

OC

YY

YY

59N

OV

60

FL81

Freq.rel.

50

Ac.Eneg51/67

OC(Idm/dir.)

50

Neg.Pha.

87G

Gen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP + REX0061

UnitX

for.



88/123

Y

G

87 N


50/51

OC49

Therm.

87Oo/a Diff51OC

50/51

OC

YY

YY

59N

OV

60

FL81

Freq.rel.

50

Ac.Eneg51/67

OC(Idm/dir.)

50

Neg.Pha.

87G

Gen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37

Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP + REX0061

UnitX

for.

Negative sequence overcurrent


89/123

From asymmetric currents, a negative sequence current

component12, is filtered out.

Negative sequence stator currents rotate in a oppositedirection from the rotor and consequently induce a

100Hz current component into the rotor.

As a consequence rotor ends can over-heat.

k is the indicator of how long (Sec.) a

generator can withstand one/unit Neg.seq.Cur.

Negative phase sequence (46)


90/123

Causes

unbalanced loads untransposed transmission circuits

unbalanced system faults

series faults

CB pole discrepancy open circuits

Features

Characteristic adjustable to I22t = KK determines the right tripping time , which is

provided by the manufacturer (one/unit Neg.seq.Cur)



91/123

Y

G

87 N


50/51

OC49

Therm.

87Oo/a Diff51OC

50/51

OC

YY

YY

51

OC

60

FL81

Freq.rel.

50

Ac.Eneg51/67

OC(Idm/dir.)

50

Neg.Pha.

87G

Gen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37

Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP + REX0061

UnitX

for.

46

Neg.Pha.



92/123

Y

G

87 N


50/51

OC49

Therm.

87Oo/a Diff51OC

50/51

OC

YY

YY

51

OC

60

FL81

Freq.rel.

50

Ac.Eneg51/67

OC(Idm/dir.)

50

Neg.Pha.

87G

Gen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37

Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP + REX0061

UnitX

for.

46

Neg.Pha.

Broken stator winding


93/123


Unsymmetrical currents

Protected object

Stator windings

Rotor

Consequences

Rotor overheating

Vibrations

Broken transformer winding


94/123

Endangering condition Unsymmetrical currents

Protected object Stator windings

Rotor

Consequences

Rotor overheating Vibrations

Diff l k fl



95/123

Y

G

87 N


50/51

OC49

Therm.

87Oo/a Diff51OC

50/51

OC

YY

YY

51

OC

60

FL81

Freq.rel.

50

Ac.Eneg51/67

OC(Idm/dir.)

50

Neg.Pha.

87G

Gen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37

Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP + REX0061

UnitX

for.

46

Neg.Pha.

Pole slip / out of step protection


96/123

Asynchronous running of a synchronous machine with the rest ofthe system but with excitation intact

Big mechanical impact on turbine and shaft

Pole Slip typically caused by: Long fault clearance time (especially close by 3Ph faults arecritical) Inadvertent tripping of a transmission line (increase oftransmission impedance between generator and load) Loss of large generator unit


E d i diti


97/123

Endangering condition High stator current

Possible system blackout

Protected object

Rotor shaft and stator winding

Consequences

Mechanical damages to shaft Asynchronous machine operation (withfield intact) Voltage and current variations

Diff l B k fl



98/123

Y

G

87 N


50/51

OC49

Therm.

87Oo/a Diff51OC

50/51

OC

YY

YY

51

OC

60

FL81

Freq.rel.

50

Ac.Eneg51/67

OC(Idm/dir.)

50

O.C

87G

Gen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37

Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP + REX0061

UnitX

for.

46

Neg.Pha.

Diff l B k fl OC



99/123

Y

G

87 N


50/51

OC49

Therm.

87Oo/a Diff51OC

50/51

OC

YY

YY

51

OC

60

FL81

Freq.rel.

50

Ac.Eneg51/67

OC(Idm/dir.)

50

Neg.Pha.

87G

Gen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37

Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP + REX0061

UnitX

for.

46

Neg.Pha.

Low frequency


100/123


Under-frequency

Protected object

Transformer

Steam turbine

Consequences

Over-excitation

Steam turbine vibrations

Diff rel Brk flr OC Th

Low frequency


101/123

Y

G

87 N


50/51

OC49

Therm.

87Oo/a Diff51OC

50/51

OC

YY

YY

51

OC

60

FL81

Freq.rel.

50

Ac.Eneg51/67

OC(Idm/dir.)

50

O.C

87G

Gen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S

100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37

Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP + REX0061

UnitX

for.

46

Neg.Pha.


Low frequency


102/123

Y

G

87 N


50/51

OC49

Therm.

87Oo/a Diff51OC

50/51

OC

YY

YY

51

OC

60

FL81

Freq.rel.

50

Ac.Eneg51/67

OC(Idm/dir.)

50

O.C

87G

Gen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S

100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37

Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP + REX0061

UnitX

for.

46

Neg.Pha.

High Frequency


103/123


Over-frequency

Protected object Turbine

Rotor

Consequences

Mechanical stresses

Turbine vibrations


Low frequency


104/123

Y

G

87 N


50/51

OC49

Therm.

87O

o/a Diff51OC

50/51

OC

YY

YY

51

OC

60

FL81

Freq.rel.

50

Ac.Eneg51/67

OC(Idm/dir.)

50

O.C

87G

Gen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S

100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37

Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP + REX0061

UnitX

for.

46

Neg.Pha.


Low frequency


105/123

Y

G

87 N


50/51

OC49

Therm.

87O

o/a Diff51OC

50/51

OC

YY

YY

51

OC

60

FL81

Freq.rel.

50

Ac.Eneg51/67

OC(Idm/dir.)

50

O.C

87G

Gen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S

100%GFP

50THD

100%GFP

+ REX0060

78

Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37

Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.64S

100%GFP + REX0061

UnitX

for.

46

Neg.Pha.


106/123

Over Voltage Protection:


107/123


Over-voltage Improper voltage regulation

Protected object

Electrical circuits

Consequences

Increased risk for earth-faults

Over-excitation

g

Diff rel Brk flr OC Therm



108/123

Y

G

87 N


50/51

OC49

Therm.

87O

o/a Diff51OC

50/51

OC

YY

YY

51

OC

60

FL81

Freq.rel.

50

Ac.Eneg51/67

OC(Idm/dir.)

50

O.C

87G

Gen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S

100%GFP

50THD

100%GFP

+ REX0060

78Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37

Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.

64S

100%GFP + REX0061

UnitX

for.

46

Neg.Pha.

Diff rel Brk flr OC Therm



109/123

Y

G

87 N


50/51

OC49

Therm.

87O

o/a Diff51OC

50/51

OC

YY

YY

51

OC

60

FL81

Freq.rel.

50

Ac.Eneg51/67

OC(Idm/dir.)

50

O.C

87G

Gen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S

100%GFP

50THD

100%GFP

+ REX0060

78Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37

Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.

64S

100%GFP + REX0061

UnitX

for.

46

Neg.Pha.

Over-fluxing


110/123

Over fluxing protection protects generator and

transformer magnetic core against overheating

Specially critical during start-up and shut-down

Wide frequency operation of the relay important forgenerator

protection


111/123

Diff.rel. Brk.flr. OC Therm



112/123

Y

G

87 N

e50BFBrk.flr.

50/51

OC49

Therm.

87O

o/a Diff51OC

50/51

OC

YY

YY

51

OC

60

FL81

Freq.rel.

50

Ac.Eneg51/67

OC(Idm/dir.)

50

O.C

87G

Gen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S

100%GFP

50THD

100%GFP

+ REX0060

78Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37

Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.

64S

100%GFP + REX0061

UnitX

for.

46

Neg.Pha.


113/123


Stator Thermal Overload


114/123

Y

G

87 N 50BF 50/51OC

49

Therm.

87O

o/a Diff51OC

50/51

OC

YY

YY

51

OC

60

FL81

Freq.rel.

50

Ac.Eneg51/67

OC(Idm/dir.)

50

O.C

87G

Gen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S

100%GFP

50THD

100%GFP

+ REX0060

78Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37

Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.

64S

100%GFP + REX0061

UnitX

for.

46

Neg.Pha.




115/123

Y

G

87 N 50BF 50/51OC

49

Therm.

87O

o/a Diff51OC

50/51

OC

YY

YY

51

OC

60

FL81

Freq.rel.

50

Ac.Eneg51/67

OC(Idm/dir.)

50

O.C

87G

Gen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S

100%GFP

50THD

100%GFP

+ REX0060

78Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37

Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.

64S

100%GFP + REX0061

UnitXfor.

46

Neg.Pha.


116/123


117/123

Diff.rel. Brk.flr. OC Therm.



118/123

Y

G

87 N 50BF 50/51 49Therm.

87O

o/a Diff51OC

50/51

OC

YY

YY

51

OC

60

FL81

Freq.rel.

50

Ac.Eneg51/67

OC(Idm/dir.)

50

O.C

87G

Gen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S

100%GFP

50THD

100%GFP

+ REX0060

78Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37

Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.

64S

100%GFP + REX0061

UnitXfor.

46

Neg.Pha.

Diff.rel. Brk.flr. OC Therm.



119/123

Y

G

87 N 50BF 50/51 49

87O

o/a Diff51OC

50/51

OC

YY

YY

51

OC

60

FL81

Freq.rel.

50

Ac.Eneg51/67

OC(Idm/dir.)

50

O.C

87G

Gen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S

100%GFP

50THD

100%GFP

+ REX0060

78Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37

Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.

64S

100%GFP + REX0061

UnitXfor.

46

Neg.Pha.

Breaker Failure (50BF)


120/123

87 N

Diff.rel.50BFBrk.flr. OC Therm.



121/123

Y

G

87 N 50BF 50/51 49

87O

o/a Diff51OC

50/51

OC

YY

YY

51

OC

60

FL81

Freq.rel.

50

Ac.Eneg51/67

OC(Idm/dir.)

50

BF

87G

Gen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S

100%GFP

50THD

100%GFP

+ REX0060

78Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37

Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.

64S

100%GFP + REX0061

UnitXfor.

46

Neg.Pha.

87 N

Diff.rel.50BFBrk.flr. OC Therm.



122/123

Y

G

87 N 50BF 50/51 49

87O

o/a Diff51

OC

50/51

OC

YY

YY

51

OC

60

FL81

Freq.rel.

50

Ac.Eneg51/67

OC(Idm/dir.)

50

BF

87G

Gen.st.dif

50

Neg.Pha.

49

Therm.

59N

O.V

64S

100%GFP

50THD

100%GFP

+ REX0060

78Out of step

21

Udr.Imp.pro.

32

Rev. Pow.

37

Under curr.

40

FIELD.EXCIT

24

OVER EXCIT

27

UND.VOL.

59

OVER.VOL.

81

FREQ.

64S

100%GFP + REX0061

UnitXfor.

46

Neg.Pha.


123/123

THANK YOU

Date post:	03-Apr-2018
Category:	Documents
Upload:	mohammad-ibnul-hossain
View:	240 times
Download:	14 times

Generator Protection Class presentation

Documents