Differential Protection - ABB Relion 670 Series Product Manual

Generator protection REG670
Version 2.2
Table 8. Basic IED functions, continued
IEC 61850 or function Description
name
ALTMS Time master supervision
ALTIM Time management
CAMCONFIG Central account management configuration
CAMSTATUS Central account management status
TOOLINF Tools information
COMSTATUS Protocol diagnostic
Table 9. Local HMI functions
IEC 61850 or function ANSI
name
LHMICTRL
LANGUAGE
SCREEN
FNKEYTY1–FNKEYTY5
FNKEYMD1–FNKEYMD5
LEDGEN
OPENCLOSE_LED
GRP1_LED1–
GRP1_LED15
GRP2_LED1–
GRP2_LED15
GRP3_LED1–
GRP3_LED15

4. Differential protection

Generator differential protection GENPDIF
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
24
Description
Local HMI signals
Local human machine language
Local HMI Local human machine screen behavior
Parameter setting function for HMI in PCM600
General LED indication part for LHMI
LHMI LEDs for open and close keys
Basic part for CP HW LED indication module
SEMOD143239-4 v10
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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 is also well
suited for protection of shunt reactors or small busduct.
Transformer differential protection T2WPDIF/
T3WPDIF
The Transformer differential protection is provided with
internal CT ratio matching, vector group compensation
and settable zero sequence current elimination.
1MRK 502 074-BEN M
M16104-3 v19
Hitachi Power Grids