Instruction manual

KRB-5377
70
Table 34 Setting 2 subscreens
No. Subscreen item *1 Setting range/Remarks *2 *3
○
1
(Monitor screen) See 5-3-2-3.
○
2
Ground fault trip mode TRIP/AL/OFF
○
3
Ground fault trip pickup current
[ICT] × (0.1-0.2-0.3-0.4-0.6-0.8-1.0-NON) (A)
○
4
Ground fault trip pickup time 0.1-0.2-0.3-0.5-1-2 (sec)
○
5
Ground fault trip I
2
t protection type OFF/ON
○
6
Line side ground fault protection mode TRIP/AL/OFF
○
7
Line side ground fault protection trip pickup
current
[ICT] × (0.1-0.2-0.3-0.4-0.6-0.8-1.0-NON) (A)
○
8
Line side ground fault protection bias current
[ICT] × (0.1-0.3-0.5-0.7-0.9-1.1-1.3-1.5) (A) *4
○
9
Line side ground fault protection bias limit 100% (fixed) *4
○
10
undervoltage alarm mode AL/OFF
○
11
Undervoltage alarm recovery voltage
[Vn] × (0.8-0.85-0.9-0.95) (V)
○
12
Undervoltage alarm pickup voltage
[Vn] × (0.4-0.6-0.8) (V)
○
13
Undervoltage alarm pickup time 0.1-0.5-1-2-5-10-15-20-30-36 (sec)
○
14
Reverse power trip mode TRIP/AL/OFF
○
15
Reverse power trip pickup power
[Pn] × (0.04-0.05-0.06-0.07-0.08-0.09-0.1-NON) (kW)
○
16
Reverse power trip pickup time 2.5-5-7.5-10-12.5-15-17.5-20 (sec)
○
17
Negative-phase sequence protection mode TRIP/AL/OFF
○
18
Negative-phase sequence protection trip
pickup current
[In] × (0.2-0.3-0.4-0.5-0.6-0.7-0.8-0.9-1.0) (A)
○
19
Negative-phase sequence protection trip
pickup time
0.4-0.8-1.2-1.6-2-2.4-2.8-3.2-3.6-4 (sec)
○
20
Pretrip alarm mode AL/OFF
◯
21
Pretrip alarm pickup current
L/R characteristic: [I
n] × (0.75-0.8-0.85-0.9-0.95-1.0) (A)
S characteristic: [In] × (0.75-0.8-0.85-0.9-0.95-1.0-1.05) (A)
◯
22
Pretrip alarm pickup time
L/R characteristic: 5-10-15-20-40-60-80-120-160-200) (sec)
S characteristic: 10-15-20-25-30 (sec)
◯
23
Pretrip alarm 2 mode AL/OFF
◯
24
Pretrip alarm 2 pickup current
[In] × (0.75-0.8-0.85-0.9-0.95-1.0-1.05) (A)
◯
25
Pretrip alarm 2 pickup time
1.5× tP1 (sec) (determined by auto calculation)
◯
26
Contact overheat monitor mode TRIP/AL/OFF
◯
27
Contact overheat alarm pickup temperature
155°C (fixed)
◯
28
Setting change mode "Start"
Press ENTER to enter this subscreen from a setting 2 subscreen. The value that can be changed will flash. To exit this
subscreen, press the right or left key of the cross button.
◯
29
Setting change mode "Setting change"
Press the up or down key of the cross button to change the setting. To exit this subscreen with no change in setting, press
the right or left key of the cross button.
◯
30
Setting change mode "Save change"
Press ENTER to enter this subscreen from subscreen ◯
29
. "SURE" will flash. To save the change, press SET. The
subscreen will exit to the Setting 2 screen. To exit this subscreen while no change is saved, press the right or left key of the
cross button.
◯
31
(Maintenance screen) See 5-3-2-8 and 5-4.
*1 If no value is found for an item, the corresponding subscreen is skipped.
*2 Underlined values are default settings.
*3 This table shows percent representations of settings. For AV representations (see 5-3-2-4), current values are indicated in A (Amperage), V (voltage),or kW (kilowatt).
*4 The line side ground fault protection bias current and bias limit are coefficients for strain. Because the line side ground fault protection function performs an arithmetic
operation using the difference between CTs with different characteristics, errors in measured line side ground fault current become significant when a large current flows
through the ACB. "Strain" is to increase the line side ground fault trip pickup current with increasing current flowing through the ACB, thus preventing malfunctions caused by
such an error. The following shows the relationship between the current flowing through the ACB and the line side ground fault protection trip pickup current under "strained"
conditions:
When ( i + iREFCT ) / 2 ≤ IREF2;
IREFNOW = IREF
When ( i + iREFCT ) / 2 > IREF2;
IREFNOW = IREF [ 1 + a { ( i + i REFCT ) / 2 IREF2 - 1 } ]
(IREF: Line side ground fault protection trip pickup current, IREF2: Line side ground fault protection bias current, a: Line side ground fault
protection bias limit, i: Max. phase current (present value), iREFCT: Line side ground fault current, IREFNOW: Line side ground fault
protection pickup current calculated using strain coefficients)
Ex.: When ( i + i
REF ) / 2 = 5 × IREF2 and other settings remain default;
I
REFNOW = IREF [ 1 + 1 × { 5 × IREF2 / IREF2 - 1 } ] = IREF [ 1 + 1× { 5 - 1 } ] = 5 × IREF
Fig. 65 Relationship between the current flowing through the ACB and the line side
ground fault protection trip pickup current under "strained" conditions
I
REF2
(
◯
8
)
I
REF
(
◯
7
)
I
REFNO
(I+I
REFCT
)/2
α × I
REF
/I
REF2
(=
◯
9
×
◯
7
/
◯
8
)