ABB Relion REG670 User manual

Relion

®

670 series

Generator protection REG670 ANSI

Customized

Product Guide

Contents

1. Application.........................................................................3

2. Available functions...........................................................10

3. Differential protection.......................................................17

4. Impedance protection......................................................20

5. Current protection............................................................20

6. Voltage protection............................................................23

7. Frequency protection.......................................................25

8. Multipurpose protection...................................................26

9. Secondary system supervision.........................................27

10. Control...........................................................................27

11. Logic..............................................................................29

12. Monitoring......................................................................30

13. Metering.........................................................................32

14. Basic IED functions.........................................................32

15. Human machine interface...............................................32

16. Station communication ..................................................33

17. Remote communication..................................................34

18. Hardware description......................................................34

19. Connection diagrams......................................................38

20. Technical data................................................................47

21. Ordering.........................................................................95

Disclaimer

Trademarks

ABB and Relion are registered trademarks of ABB Group. All other brand or product names mentioned in this document may be trademarks or registered trademarks of

their respective holders.

Generator protection REG670 ANSI 1MRK 502 031-BUS B

Customized

Product version: 1.2

2 ABB

1. Application

The REG670 is used for protection, control and

monitoring of generators and generator-transformer

blocks from relatively small units up to the largest

generating units. The IED has a comprehensive

function library, covering the requirements for most

generator applications. The large number of analog

inputs available enables, together with the large

functional library, integration of many functions in

one IED. In typical applications two units can

provide total functionality, also providing a high

degree of redundancy. REG670 can as well be used

for protection and control of shunt reactors.

Stator ground fault protection, both traditional 95%

as well as 100% injection and 3rd harmonic based

are included. When the injection based protection is

used, 100% of the machine stator winding,

including the star point, is protected under all

operating modes. The 3rd harmonic based 100%

stator earth fault protection uses 3rd harmonic

differential voltage principle. Injection based 100%

stator ground fault protection can operate even

when machine is at standstill. Well proven

algorithms for pole slip, underexcitation, rotor

ground fault, negative sequence current

protections, and so on, are included in the IED.

The generator differential protection in the REG670

adapted to operate correctly for generator

applications where factors as long DC time

constants and requirement on short trip time have

been considered.

As many of the protection functions can be used as

multiple instances there are possibilities to protect

more than one object in one IED. It is possible to

have protection for an auxiliary power transformer

integrated in the same IED having main protections

for the generator. The concept thus enables very

cost effective solutions.

The REG670 also enables valuable monitoring

possibilities as many of the process values can be

transferred to an operator HMI.

The wide application flexibility makes this product

an excellent choice for both new installations and

for refurbishment in existing power plants.

Serial data communication is via optical

connections to ensure immunity against

disturbances.

The wide application flexibility makes this product

an excellent choice for both new installations and

the refurbishment of existing installations.

By using patented algorithm REG670 (or any other

product from 670 series) can track the power

system frequency in quite wide range from 9Hz to

95Hz. In order to do that preferably the three-phase

voltage signal from the generator terminals shall be

connected to the IED. Then IED can adopt its

filtering algorithm in order to properly measure

phasors of all current and voltage signals connected

to the IED. This feature is essential for proper

operation of the protection during generator start-

up and shut-down procedure.

Generator protection REG670 ANSI 1MRK 502 031-BUS B

Customized

Product version: 1.2 Issued: May 2012

Revision: B

ABB 3

IEC11000201-1-en.vsd

G

U

STEF PHIZ

59THD U3d/N

GEN PDIF

87G 3Id/I

SA PTUF

81 f<

SA PTOF

81 f>

SDD RFUF

60FL

OEX PVPH

24 U/f>

UV2 PTUV

27 3U<

OV2 PTOV

59 3U>

REG 670*1.2

ZMH PDIS

21 Z<

LEX PDIS

40 <

GUP PDUP

37 P<

GOP PDOP

32 P

ROV2 PTOV

59N 3Uo>

OC4 PTOC

51/67 3I->

CC RBRF

50BF 3I> BF

NS2 PTOC

46 I2>

TR PTTR

49 Ith

PSP PPAM

78 Ucos

+ REX060, REX061

AEG GAPC

50AE U/I>

CV MMXU

Meter.

ROV2 PTOV

59N UN>

ROTI PHIZ

64R R

RE

<

STTI PHIZ

64S R

SE

<

+ REX060

ROV2 PTOV

59N 3Uo>

VT

Y

D

IEC11000201 V1 EN

Figure 1. Generator protection application with generator differential, 100% stator ground fault and back-up protection

Generator protection REG670 ANSI 1MRK 502 031-BUS B

Customized

Product version: 1.2

4 ABB

IEC11000204-1-en.vsd

G

U

GEN PDIF

87G 3Id/I

SA PTUF

81 f<

SA PTOF

81 f>

SDD RFUF

60FL

OEX PVPH

24 U/f>

UV2 PTUV

27 3U<

OV2 PTOV

59 3U>

REG 670*1.2

ZMH PDIS

21 Z<

LEX PDIS

40 <

GUP PDUP

37 P<

GOP PDOP

32 P

ROV2 PTOV

59N 3Uo>

OC4 PTOC

51/67 3I->

CC RBRF

50BF 3I> BF

NS2 PTOC

46 I2>

PSP PPAM

78 Ucos

+ REX060, REX061

AEG GAPC

50AE U/I>

CV MMXU

Meter.

ROTI PHIZ

64R R

RE

<

STTI PHIZ

64S R

SE

<

+ REX060

ROV2 PTOV

59N 3Uo>

VT

EF4 PTOC

64W IN>

Y

S

D

IEC11000204 V1 EN

Figure 2. Generator protection application for generator with split winding including generator phase differential,

100% stator ground fault and back-up protection

Generator protection REG670 ANSI 1MRK 502 031-BUS B

Customized

Product version: 1.2

ABB 5

IEC11000206-1-en.vsd

G

U

STEF PHIZ

59THD U3d/N

GEN PDIF

87G 3Id/I

SA PTUF

81 f<

SA PTOF

81 f>

SDD RFUF

60FL

OEX PVPH

24 U/f>

UV2 PTUV

27 3U<

OV2 PTOV

59 3U>

REG 670*1.2

ZMH PDIS

21 Z<

LEX PDIS

40 <

GUP PDUP

37 P<

GOP PDOP

32 P

ROV2 PTOV

59N 3Uo>

OC4 PTOC

51/67 3I->

CC RBRF

50BF 3I> BF

NS2 PTOC

46 I2>

PSP PPAM

78 Ucos

+ REX060, REX061

AEG GAPC

50AE U/I>

CV MMXU

Meter.

ROV2 PTOV

59N UN>

ROTI PHIZ

64R R

RE

<

VT

EF4 PTOC

64W IN>

Y

STTI PHIZ

64S R

SE

<

+ REX060

VT

GEN PDIF

87W 3Id/I

D

S

IEC11000206 V1 EN

Figure 3. Generator protection application for generator with split winding including generator phase differential,

generator split-phase differential, 100% stator ground fault and back-up protection

Generator protection REG670 ANSI 1MRK 502 031-BUS B

Customized

Product version: 1.2

6 ABB

IEC11000202-1-en.vsd

G

U

ROV2 PTOV

59N UN>

GEN PDIF

87G 3Id/I

SA PTUF

81 f<

SA PTOF

81 f>

SDD RFUF

60FL

REG 670*1.2

ZMH PDIS

21 Z<

LEX PDIS

40 <

GUP PDUP

37 P<

GOP PDOP

32 P

OC4 PTOC

51/67 3I->

CC RBRF

50BF 3I> BF

NS2 PTOC

46 I2>

TR PTTR

49 Ith

PSP PPAM

78 Ucos

AEG GAPC

50AE U/I>

STEF PHIZ

59THD U3d/N

Auxiliary Bus

OC4 PTOC

50/51 3I>

OC4 PTOC

50/51 3I>

CC RBRF

50BF 3I> BF

OC4 PTOC

50/51 3I>

ROV2 PTOV

59N 3Uo>

T3W PDIF

87T 3Id/I

CV MMXU

Meter.

OEX PVPH

24 U/f>

UV2 PTUV

27 3U<

OV2 PTOV

59 3U>

ROV2 PTOV

59N 3Uo>

+ REX060, REX061

STTI PHIZ

64S R

SE

<

ROTI PHIZ

64R R

RE

<

+ REX060, REX062

Y

Unit Trafo

A

u

x

i

l

i

a

r

y

T

r

a

f

o

E

x

c

i

t

a

t

i

o

n

T

r

a

f

o

Y

Grounding

Transformer

D

IEC11000202 V1 EN

Figure 4. Unit protection application with overall differential, generator differential, 100% stator ground fault and back-

up protection. Stator winding grounded via grounding transformer.

Generator protection REG670 ANSI 1MRK 502 031-BUS B

Customized

Product version: 1.2

ABB 7

IEC11000203-1-en.vsd

G

U

STEF PHIZ

59THD U3d/N

TR PTTR

49 Ith

SA PTUF

81 f<

EF4 PTOC

50N/51N

IN>

REF PDIF

87N IdN/I

T3W PDIF

87O 3Id/I

REG 670*1.2

T2W PDIF

87T 3Id/I

ROV2 PTOV

59N 3Uo>

NS2 PTOC

46 I2>

TR PTTR

49 Ith

SDD RFUF

60FL

ZMH PDIS

21 Z<

LEX PDIS

40 <

GUP PDUP

37 P<

GOP PDOP

32 P

PSP PPAM

78 Ucos

SA PTOF

81 f>

OEX PVPH

24 U/f>

UV2 PTUV

27 3U<

OV2 PTOV

59 3U>

OC4 PTOC

50/51 3I>

OC4 PTOC

50/51 3I>

CC RBRF

50BF 3I> BF

GEN PDIF

87G 3Id/I

ROV2 PTOV

59N UN>

CC RBRF

50BF 3I> BF

OC4 PTOC

51/67 3I->

AEG GAPC

50AE U/I>

CV MMXU

Meter.

+ REX060, REX061

STTI PHIZ

64S R

SE

<

ROTI PHIZ

64R R

RE

<

+ REX060

CV MMXU

Meter.

Y

U

n

i

t

T

r

a

f

o

VT

D

IEC11000203 V1 EN

Figure 5. Unit protection application with overall differential, unit transformer differential, generator differential, 100%

stator ground fault and back-up protection. Ungrounded stator winding.

Generator protection REG670 ANSI

1MRK 502 031-BUS B

Customized

Product version: 1.2

8 ABB

G

U

TR PTTR

49 Ith

SA PTUF

81 f<

EF4 PTOC

50N/51N

IN>

REF PDIF

87N IdN/I

T3W PDIF

87O 3Id/I

REG 670*1.2

T2W PDIF

87T 3Id/I

ROV2 PTOV

59N 3Uo>

NS2 PTOC

46 I2>

TR PTTR

49 Ith

SDD RFUF

60FL

ZMH PDIS

21 Z<

LEX PDIS

40 <

GUP PDUP

37 P<

GOP PDOP

32 P

PSP PPAM

78 Ucos

SA PTOF

81 f>

OEX PVPH

24 U/f>

UV2 PTUV

27 3U<

OV2 PTOV

59 3U>

OC4 PTOC

50/51 3I>

OC4 PTOC

50/51 3I>

CC RBRF

50BF 3I> BF

GEN PDIF

87G 3Id/I

CC RBRF

50BF 3I> BF

OC4 PTOC

51/67 3I->

AEG GAPC

50AE U/I>

CV MMXU

Meter.

+ REX060, REX061

STTI PHIZ

64S R

SE

<

ROTI PHIZ

64R R

RE

<

+ REX060

CV MMXU

Meter.

Y

U

n

i

t

T

r

a

f

o

ROV2 PTOV

59N 3Uo>

VT

IEC11000207-1-en.vsd

D

IEC11000207 V1 EN

Figure 6. Unit protection application with overall differential, unit transformer differential, generator differential, 100%

stator ground fault and back-up protection. Stator winding grounded via primary resistor.

Generator protection REG670 ANSI 1MRK 502 031-BUS B

Customized

Product version: 1.2

ABB 9

2. Available functions

Main protection functions

2 = number of basic instances

0-3 = option quantities

IEC 61850 ANSI Function description Generator

REG670

Differential protection

T2WPDIF 87T Transformer differential protection, two winding 0-2

T3WPDIF 87T Transformer differential protection, three winding 0-2

HZPDIF 87 1Ph high impedance differential protection 0-6

GENDIF 87G Generator differential protection 0-2

REFPDIF 87N Restricted earth fault protection, low impedance 0-3

Impedance protection

ZMHPDIS 21 Full-scheme distance protection, mho characteristic 0-4

ZDMRDIR 21D Directional impedance element for mho characteristic 0-2

PSPPPAM 78 Pole slip/out-of-step protection 0-1

LEXPDIS 40 Loss of excitation 0-2

Generator protection REG670 ANSI 1MRK 502 031-BUS B

Customized

Product version: 1.2

10 ABB

Back-up protection functions

IEC 61850 ANSI Function description Generator

REG670

Current protection

PHPIOC 50 Instantaneous phase overcurrent protection 0-4

OC4PTOC 51_67 Four step phase overcurrent protection 0-6

EFPIOC 50N Instantaneous residual overcurrent protection 0-2

EF4PTOC 51N_67

N

Four step residual overcurrent protection 0-6

NS4PTOC 46I2 Four step directional negative phase sequence overcurrent protection 0-2

SDEPSDE 67N Sensitive directional residual overcurrent and power protection 0-2

TRPTTR 49 Thermal overload protection, two time constant 0-3

CCRBRF 50BF Breaker failure protection 0-4

CCRPLD 52PD Pole discordance protection 0-4

GUPPDUP 37 Directional underpower protection 0-4

GOPPDOP 32 Directional overpower protection 0-4

NS2PTOC 46I2 Negative sequence time overcurrent protection for machines 0-2

AEGGAPC 50AE Accidental energizing protection for synchronous generator 0-2

Voltage protection

UV2PTUV 27 Two step undervoltage protection 0-2

OV2PTOV 59 Two step overvoltage protection 0-2

ROV2PTOV 59N Two step residual overvoltage protection 0-3

OEXPVPH 24 Overexcitation protection 0-2

VDCPTOV 60 Voltage differential protection 0-2

STEFPHIZ 59THD 100% stator earth fault protection, 3rd harmonic based 0-1

Frequency protection

SAPTUF 81 Underfrequency protection 0-6

SAPTOF 81 Overfrequency protection 0-6

SAPFRC 81 Rate-of-change frequency protection 0-3

Generator protection REG670 ANSI 1MRK 502 031-BUS B

Customized

Product version: 1.2

ABB 11

IEC 61850 ANSI Function description Generator

REG670

Multipurpose protection

CVGAPC General current and voltage protection 1-12

64R Rotor earth fault 1

Generator protection REG670 ANSI 1MRK 502 031-BUS B

Customized

Product version: 1.2

12 ABB

Control and monitoring functions

IEC 61850 ANSI Function description Generator

REG670

Control

SESRSYN 25 Synchrocheck, energizing check and synchronizing 0-2

APC30 3 Apparatus control for up to 6 bays, max 30 apparatuses (6CBs) incl.

interlocking

0-1

QCBAY Apparatus control 1

Local

Remote

Handling of LRswitch positions 1

LocRem

Control

LHMI control of PSTO 1

TCMYLTC 84 Tap changer control and supervision, 6 binary inputs 0-4

TCLYLTC 84 Tap changer control and supervision, 32 binary inputs 0-4

SLGGIO Logic rotating switch for function selection and LHMI presentation 15

VSGGIO Selector mini switch 20

DPGGIO IEC61850 generic communication I/O functions 16

SPC8GGIO Single pole generic control 8 signals 5

AutomationBits AutomationBits, command function for DNP3.0 3

Single command, 16 signals 4

Secondary system supervision

CCSRDIF 87 Current circuit supervision 0-5

SDDRFUF Fuse failure supervision 0-3

Logic

SMPPTRC 94 Tripping logic 1-6

TMAGGIO Trip matrix logic 12

Configuration logic blocks 40-280

Fixed signal function blocks 1

B16I Boolean 16 to Integer conversion 16

B16IFCVI Boolean 16 to Integer conversion with Logic Node representation 16

IB16 Integer to Boolean 16 conversion 16

IB16FVCB Integer to Boolean 16 conversion with Logic Node representation 16

Generator protection REG670 ANSI 1MRK 502 031-BUS B

Customized

Product version: 1.2

ABB 13

IEC 61850 ANSI Function description Generator

REG670

Monitoring

CVMMXN Measurements 6

CNTGGIO Event counter 5

Event Event function 20

DRPRDRE Disturbance report 1

SPGGIO IEC61850 generic communication I/O functions 64

SP16GGIO IEC61850 generic communication I/O functions 16 inputs 16

MVGGIO IEC61850 generic communication I/O functions 24

BSStart

Report

Logical signal status report 3

RANGE_XP Measured value expander block 66

Metering

PCGGIO Pulse-counter logic 16

ETPMMTR Function for energy calculation and demand handling 6

Generator protection REG670 ANSI 1MRK 502 031-BUS B

Customized

Product version: 1.2

14 ABB

Designed to communicate

IEC 61850 ANSI Function description Generator

REG670

Station communication

DNP3.0 for TCP/IP and EIA-485

communication protocol

1

DNP3.0 fault records for TCP/IP and

EIA-485 communication protocol

1

Parameter setting function for

IEC61850

1

IntlReceive Horizontal communication via

GOOSE for interlocking

59

Goose binary receive 10

Multiple command and transmit 60/10

Ethernet configuration of links 1

IEC 62439-3 Edition 1 parallel

redundancy protocol

0-1

IEC 62439-3 Edition 2 parallel

redundancy protocol

0-1

Generator protection REG670 ANSI 1MRK 502 031-BUS B

Customized

Product version: 1.2

ABB 15

Basic IED functions

IEC 61850 Function description

Basic functions included in all products

IntErrorSig Self supervision with internal event list 1

TIME Time and synchronization error 1

TimeSynch Time synchronization 1

ActiveGroup Parameter setting groups 1

Test Test mode functionality 1

ChangeLock Change lock function 1

TerminalID IED identifiers 1

Productinfo Product information 1

MiscBaseCommon Misc Base Common 1

IEDRuntimeComp IED Runtime Comp 1

RatedFreq Rated system frequency 1

SMBI Signal Matrix for binary inputs 40

SMBO Signal Matrix for binary outputs 40

SMMI Signal Matrix for mA inputs 4

SMAI Signal Matrix for analog inputs 36

Sum3Ph Summation block 3 phase 18

LocalHMI Parameter setting function for HMI in PCM600 1

LocalHMI Local HMI signals 1

AuthStatus Authority status 1

AuthorityCheck Authority check 1

AccessFTP FTP access with password 1

SPACommMap SPA communication mapping 1

DOSFRNT Denial of service, frame rate control for front port 1

DOSOEMAB Denial of service, frame rate control for OEM port AB 1

DOSOEMCD Denial of service, frame rate control for OEM port CD 1

Generator protection REG670 ANSI 1MRK 502 031-BUS B

Customized

Product version: 1.2

16 ABB

3. Differential protection

Generator differential protection GENPDIF (87G)

Short circuit between the phases of the stator

windings causes normally very large fault currents.

The short circuit gives risk of damages on

insulation, windings and stator iron core. The large

short circuit currents cause large forces, which can

cause damage even to other components in the

power plant, such as turbine and generator-turbine

shaft.

To limit the damage due to stator winding short

circuits, the fault clearance must be as fast as

possible (instantaneous). If the generator block is

connected to the power system close to other

generating blocks, the fast fault clearance is

essential to maintain the transient stability of the

non-faulted generators.

Normally, the short circuit fault current is very large,

that is, significantly larger than the generator rated

current. There is a risk that a short circuit can occur

between phases close to the neutral point of the

generator, thus causing a relatively small fault

current. The fault current can also be limited due to

low excitation of the generator. Therefore, it is

desired that the detection of generator phase-to-

phase short circuits shall be relatively sensitive,

detecting small fault currents.

It is also of great importance that the generator

differential protection does not trip for external

faults, with large fault currents flowing from the

generator.

To combine fast fault clearance, as well as

sensitivity and selectivity, the generator differential

protection is normally the best choice for phase-to-

phase generator short circuits.

Generator differential protection GENPDIF (87G) is

also well suited to generate fast, sensitive and

selective fault clearance, if used to protect shunt

reactors or small busduct.

Transformer differential protection T2WPDIF/

T3WPDIF (87T)

The Transformer differential protection, two-winding

(T2WPDIF, 87T) and Transformer differential

protection, three-winding (T3WPDIF, 87T) are

provided with internal CT ratio matching and phase

shift compensation and settable zero sequence

current elimination.

The function can be provided with up to three-

phase sets of current inputs. All current inputs are

provided with percentage bias restraint features,

making the IED suitable for two- or three-winding

transformer in multi-breaker station arrangements.

Generator protection REG670 ANSI 1MRK 502 031-BUS B

Customized

Product version: 1.2

ABB 17

Two-winding applications

xx05000048_ansi.vsd

152

352

ANSI05000048 V1 EN

two-winding power transformer

xx05000049_ansi.vsd

152

352

ANSI05000049 V1 EN

two-winding power transformer with

unconnected delta tertiary winding

xx05000050_ansi.vsd

352

252

152

ANSI05000050 V1 EN

two–winding power transformer with two circuit

breakers on one side

xx05000051_ansi.vsd

252

152

352

452

ANSI05000051 V1 EN

two–winding power transformer with two circuit

breakers and two CT-sets on both sides

Three-winding applications

xx05000052_ansi.vsd

352

152

452

ANSI05000052 V1 EN

three–winding power transformer with all three

windings connected

Generator protection REG670 ANSI 1MRK 502 031-BUS B

Customized

Product version: 1.2

18 ABB

xx05000053_ansi.vsd

352

452

252

152

ANSI05000053 V1 EN

three–winding power transformer with two circuit

breakers and two CT-sets on one side

xx05000057_ansi.vsd

552

152 252

352 452

ANSI05000057 V1 EN

Autotransformer with two circuit breakers and

two CT-sets on two out of three sides

Figure 7. CT group arrangement for

differential protection and other

protections

The setting facilities cover the applications of the

differential protection to all types of power

transformers and auto-transformers with or without

load tap changer as well as for shunt reactors or

and local feeders within the station. An adaptive

stabilizing feature is included for heavy through-

faults.By introducing the load tap changer position,

the differential protection pick-up can be set to

optimum sensitivity thus covering internal faults with

low fault level.

Harmonic restraint is included for inrush currents as

well as for overexcitation conditions. Adaptive

stabilization is also included for system recovery

inrush and CT saturation for external faults. A high

set unrestrained differential current protection is

included for a very high speed tripping at a high

internal fault currents.

An innovative sensitive differential protection

feature, based on the theory of symmetrical

components, offers the best possible coverage for

power transformer winding turn-to-turn faults.

1Ph High impedance differential protection HZPDIF

(87)

The 1Ph High impedance differential protection

(HZPDIF, 87) function can be used when the

involved CTs have the same turns ratio and similar

magnetizing characteristics. It utilizes an external

CT current summation by wiring, a series resistor,

and a voltage dependent resistor which are

mounted externally connected to the IED.

HZPDIF (87) can be used to protect generator

stator windings, tee-feeders or busbars. Six single

phase function blocks are available to allow

application for two three-phase zones busbar

protection.

Restricted earth fault protection, low impedance

REFPDIF (87N)

Restricted earth-fault protection, low-impedance

function (REFPDIF, 87N) can be used on all solidly

or low-impedance grounded windings. The

REFPDIF (87N) function provides high sensitivity

(down to 5%) and high speed tripping as it

measures each winding individually and thus does

not need inrush stabilization.

The low-impedance function is a percentage biased

function with an additional zero sequence current

directional comparison criterion. This gives excellent

sensitivity and stability during through faults. The

function allows the use of different CT ratios and

magnetizing characteristics on the phase and

neutral CT cores and mixing with other functions

and protection IEDs on the same cores.

Generator protection REG670 ANSI

1MRK 502 031-BUS B

Customized

Product version: 1.2

ABB 19

4. Impedance protection

Full-scheme distance measuring, Mho

characteristic ZMHPDIS (21)

The numerical mho line distance protection is a four

zone full scheme protection for back-up detection

of short circuit and ground faults. The four zones

have fully independent measuring and settings,

which gives high flexibility for all types of lines.

The function can be used as under impedance back-

up protection for transformers and generators.

Directional impedance element for Mho

characteristic ZDMRDIR

The phase-to-ground impedance elements can be

optionally supervised by a phase unselective

directional function (phase unselective, because it is

based on symmetrical components).

Pole slip protection PSPPPAM (78)

The situation with pole slip of a generator can be

caused by different reasons.

A short circuit may occur in the external power grid,

close to the generator. If the fault clearing time is

too long, the generator will accelerate so much, that

the synchronism cannot be maintained.

Un-damped oscillations occur in the power system,

where generator groups at different locations,

oscillate against each other. If the connection

between the generators is too weak the magnitude

of the oscillations will increase until the angular

stability is lost.

The operation of a generator having pole slip will

give risk of damages to the generator, shaft and

turbine.

• At each pole slip there will be significant torque

impact on the generator-turbine shaft.

• In asynchronous operation there will be

induction of currents in parts of the generator

normally not carrying current, thus resulting in

increased heating. The consequence can be

damages on insulation and stator/rotor iron.

The Pole slip protection (PSPPPAM ,78) function

shall detect pole slip conditions and trip the

generator as fast as possible if the locus of the

measured impedance is inside the generator-

transformer block. If the centre of pole slip is

outside in the power grid, the first action should be

to split the network into two parts, after line

protection action. If this fails there should be

operation of the generator PSPPPAM (78) in zone 2,

to prevent further damages to the generator, shaft

and turbine.

Loss of excitation LEXPDIS (40)

There are limits for the under-excited operation of a

synchronous machine. A reduction of the excitation

current weakens the coupling between the rotor

and the stator. The machine may lose the

synchronism and start to operate like an induction

machine. Then, the reactive power consumption will

increase. Even if the machine does not loose

synchronism it may not be acceptable to operate in

this state for a long time. Reduction of excitation

increases the generation of heat in the end region of

the synchronous machine. The local heating may

damage the insulation of the stator winding and the

iron core.

To prevent damages to the generator it should be

tripped when excitation is lost.

5. Current protection

Instantaneous phase overcurrent protection

PHPIOC (50)

The instantaneous three phase overcurrent function

has a low transient overreach and short tripping

time to allow use as a high set short-circuit

protection function.

Four step phase overcurrent protection OC4PTOC

(51/67)

The four step phase overcurrent protection function

OC4PTOC (51/67) has independent inverse time

delay settings for step 1 and 4. Step 2 and 3 are

always definite time delayed.

All IEC and ANSI inverse time characteristics are

available together with an optional user defined time

characteristic.

Generator protection REG670 ANSI

1MRK 502 031-BUS B

Customized

Product version: 1.2

20 ABB

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