Zero-Sequence Voltage Unit; Disturbance Recorder - ABB REJ 527 Product Manual

Directional or Non-Directional Earth-Fault
Relay
It is possible to block the start and the trip-
ping of an earth-fault stage by applying an
external binary input signal to the relay.
The low-set stage of the earth-fault unit can
be given either a definite-time or an inverse
IDMT characteristic. At IDMT characteristic,
six time/current curve groups are available, of
which four comply with the IEC 60255 stan-
dard: the normal inverse, very inverse,
extremely inverse and long time inverse. The
two additional IDMT curve groups, referred
to as RI and RD, are special curve groups
according to ABB praxis.
The inverse-time function of stage I
set to be inhibited when stage I
this case the operate time will be determined
by stage I >>.
0
The high-set stage can be set out of operation.
This state will be indicated by dashes on the
LCD and by "999" when the set start value is
read via serial communication.
The set start value of stage I
matically doubled in a start situation, e.g.
when the object to be protected is connected
to a distribution network. Thus a set start
value below the connection inrush current
level may be selected for stage I
situation is defined as a situation where the
earth-fault current rises from a value below
12% x I > to a value above 150% x I
0
than 60 ms. The start situation ends when the
current falls below 125% x I

Zero-sequence voltage unit

When the zero-sequence voltage exceeds the
set start value of low-set stage U
age unit will start to deliver a start signal after
a ~70 ms' start time. When the set operate
time at definite-time characteristic elapses,
the voltage unit will deliver a trip signal.
The two current stages, I > and I
0
replaced by two additional voltage stages,
low-set stage U > and high-set stage U
0
create a three-stage zero-sequence voltage
module. All three voltage stages measure the
same voltage but can have separate settings
both regarding sensitivity and operate time.
The signalling and trip relays can also be
selected separately for all three stages.
When the zero-sequence voltage exceeds the
set start value of low-set stage U
age unit will start to deliver a start signal after
a ~70 ms' start time. When the set operate
time at definite-time characteristic elapses,
the voltage unit will deliver a trip signal.
When the zero-sequence voltage exceeds the
set start value of high-set stage U
voltage unit will start to deliver a start signal
after a ~60 ms' start time. When the set oper-
ate time elapses, the voltage unit will deliver
a trip signal.
It is possible to block the start and the trip-
ping of a voltage stage by applying an exter-
nal binary input signal to the relay.
> can be High-set stage U
0
>> starts. In tion. This state will be indicated by dashes on
0
the LCD and by "999"when the set start value
is read via serial communication.
Circuit breaker failure
protection (CBFP) unit
The CBFP unit will generate a trip signal via
power output 2 (PO2) if the fault has not been
cleared on expiration of the set operate time
>> can be auto-
0
0.10 s...1.00 s.
Normally, the CBFP unit controls the up-
stream circuit breaker. It can also be used for
tripping via redundant trip circuits of the
>>. A start
0
same circuit breaker. The CBFP unit is acti-
vated with a software switch.
> in less
0

Disturbance recorder

>.
T
he REJ 527 includes an internal disturbance
0
recorder which records the momentary mea-
sured values, or the RMS curves of the mea-
sured signals, and seven digital signals: the
external binary input signal and the states of
>, the volt-
0b
the internal protection stages. The distur-
bance recorder can be set to be triggered by a
start or a trip signal from any protection stage
and/or by an external binary input signal, and
either on the falling or rising triggering edge.
The ratio of the pre- and post-triggering of
>>, can be
0
the recording can be set.
>>, to
0
The recording length varies according to the
selected sampling frequency. The RMS curve
is recorded by selecting the sampling fre-
quency to be the same as the nominal fre-
quency of the relay. See the table below for
details:
Nominal
>, the volt-
frequency Hz
0
1MRS751132-MBG
>> can be set out of opera-
0
Sampling Recording
frequency Hz length s
50 800
50 400
50 50
REJ 527
>>, the
0
1.20
2.40
19.20
5