KRB-5404
51
5-2-3. S characteristic for generator protection
Characteristic settings and characteristic curves of the type AGR-21BS/22BS/31BS OCR (with S characteristic) are shown in Table
25 and Figs. 48 and 49 respectively.
Table. 25 Characteristic settings of type AGR-21BS,22BS,31BS OCR (with S characteristic)
Setting item
Symbol
Setting range
○
1
Rated current
○
2
I
n
CT rated primary current [
I
CT
] × (0.5 to 1.0) (A): Fixed to a single point
Long time delay trip
(LT)
○
3
Current setting
(continuous energization)
I
R
[
I
n
] × (0.8-1.0-1.05-1.1-1.15-NON) (A), Tolerance:
5%
○
4
Time setting
t
R
(15-20-25-30-40-50-60) (sec) at 120% of [
I
R
], Tolerance:
15%, +0.15 s
–0 s
Short time delay trip
(ST)
○
5
Current setting
I
sd
[
I
n
] x (2-2.5-2.7-3-3.5-4-4.5-5-NON) (A), Tolerance:
10%
○
4
Time setting
○
6
t
sd
Relaying time (ms.)
100
200
300
400
600
800
–
Resettable time (ms.)
75
175
275
375
575
775
Max. total clearing time (ms.)
170
270
370
470
670
870
I
2
t protection type
I
2
t
t
sd
OFF/ON
○
7
Instantaneous trip
(INST/MCR)
Current setting
I
i
[
I
n
] × (2-4-6-8-10-12-14-16-NON) (A), Tolerance:
20%
○
4
INST/MCR
INST/MCR
Reverse power trip
(RPT)
○
8
Power setting
P
R
[
P
n
] × (0.04-0.05-0.06-0.07-0.08-0.09-0.1-NON) (kW), Tolerance: +0% -20%
○
4
Time setting
–
(2.5-5-7.5-10-12.5-15-17.5-20) (sec) at 100% of [
P
R
], Tolerance:
20% +0.15s
–0 s
Polarity
–
NOR/REV
○
9
Mode
–
TRIP/AL/OFF
○
10
Contact overheat
monitoring
(OH)
Temperature setting
–
155
C
Time setting
–
Instantaneous
Mode
–
TRIP/AL/OFF
○
10
Zone interlock (Z)
○
11
Current setting
–
Short time delay trip and/or ground fault trip pickup current
Time setting
–
50 ms. or less
Pretrip alarm (PTA)
Current setting
I
P1
[
I
n
] × (0.75-0.8-0.85-0.9-0.95-1.0-1.05) (A) , Tolerance:
5%
Time setting
t
P1
(10-15-20-25-30) (sec) at 120% of [
I
P1
], Tolerance:
15%, +0.1s
–0 s
Mode
–
AL/OFF
○
12
Pretrip alarm
(PTA2)
Current setting
I
P2
[
I
n
] × (0.75-0.8-0.85-0.9-0.95-1.0-1.05) (A), Tolerance:
5%
Time setting
t
P2
(1.5 x
t
P1
) (sec) at 120% of [
I
P2
], Tolerance:
15%, +0.1s
–0 s
Mode
–
AL/OFF
○
12
Undervoltage alarm
○
13
○
14
Voltage setting
–
[
V
n
] × (0.4-0.6-0.8) (V), Tolerance:
5%
Time setting
–
(0.1-0.5-1-2-5-10-15-20-30-36) (sec) at voltage setting or less, Tolerance:
±
15%, +0.1s
–0s
Recovery voltage setting
○
15
–
[
V
n
] x (0.8-0.85-0.9-0.95) (V), Tolerance:
5%
Mode
–
AL/OFF
○
12
○
1
Underlined values are default settings.
○
2
Cannot be changed by the user.
○
3
The operating time (
t
) at a long time delay trip (or pretrip alarm) pickup current setting
is given by
t
= 1.44 ×
t
R
× (
I
R
/
i
)
2
±15% +0.15
–0 [sec]
(
I
R
: Long time delay trip or pretrip alarm pickup current setting,
i
: Overcurrent value,
t
R
: Time setting)
○
4
NON setting disables protective functions. If the short time delay trip function and the
instantaneous trip (or MCR) function are both attempted to be set to NON, however,
the fail-safe operates so that:
• When the short time delay trip function has been set to NON, the instantaneous trip
function cannot be set to NON or MCR.
• When the instantaneous trip function has been set to NON or MCR, the short time
delay trip function cannot be set to NON.
○
5
The short time delay trip function has precedence over the long time delay trip
function. The OCR operates at the short time delay trip timing even in those current
ranges in which the long time delay trip time setting is shorter than the short time
delay time setting.
○
6
If DC24V zone interlock power is not provided between
□
33
and
□
34
, the zone interlock
is inoperative and the short time delay trip function works with a total clearing time of
50 ms or less when a fault current is detected.
○
7
Fig. 48 shows the operating characteristic at I
2
t ON and I
2
t
OFF. When I
2
t is ON, the
OCR operates at fixed trip pickup current of 500% of [
I
n
].
○
8
The operating time (
t
) at a reverse power trip pickup current setting is given by
t
= 0.429 ×
t
RP
/ { (
P
/0.7
P
R
) -1 }
20% [sec]
(
P
R
: Reverse power trip pickup current setting,
P
: Reverse power value,
t
RP
: Time setting)
○
9
Select NOR when the power supply of the load is upstream of the breaker and REV when it is downstream of the breaker. (See 5-3-2-4).
○
10
"TRIP" means the breaker is tripped open and operation indication is provided, "AL" means the breaker is not tripped and only operation indication is provided, and "OFF"
means the breaker is not tripped open and no operation indication is provided.
○
11
Activated only when the fault point is within the zone covered by the breaker.
○
12
"AL" means operation indication is provided and "OFF" means no operation indication is provided.
○
13
Provides an alarm and delivers contact output when the voltage of the main circuit decreases to the voltage setting or lower for longer than the time setting. The alarm ceases
when the main circuit voltage returns to the recovery voltage or higher.
○
14
When this capability is used in conjunction with the undervoltage trip device (UVT), an alarm may be provided after tripping operation of the breaker depending on the voltage
setting.
○
15
The undervoltage alarm capability does not work if the main circuit voltage is originally under the recovery voltage.
Fig. 48 I
2
t characteristic
