LS Industrial Systems Metasol Series - Ground Fault

35
D
Digital Trip Relay
D
4. Relay Function
Ground Fault
Long-Time
Delay(L)
Short-Time
Delay(S)
Instantane
ous(I)
Ground
Fault
Maximum time delay(sec)
Accuracy:15% or below 100ms
Continuous Thermal Memory Time
Current Setting(A)
Accuracy:10% or below 50ms
Maximum time delay(s)
@ 10 Ir
Current Setting(A)
Tripping time
Current Setting(A)
Accuracy:10%(Ig0.4In)
20% (Ig0.4 In) or below 50ms
Maximum time delay(s)
@ 1 In
tr @ (1.5 Ir)
tr @ (6.0 Ir)
tr @ (7.2 Ir)
Isd= Ir ...
Tsd
Ii= In ...
Ig= In ...
tg
12.5
0.5
0.34
1.5
0.05
20
80
2
0.2
0.05
20
80
25
1
0.69
2
0.1
0.1
80
140
3
0.3
0.1
0.1
80
140
50
2
1.38
3
0.2
0.2
160
240
4
0.4
0.2
0.2
160
240
100
4
2.7
4
0.3
0.3
260
340
6
0.5
0.3
0.3
260
340
200
8
5.5
5
0.4
0.4
360
440
8
0.6
0.4
0.4
360
440
300
12
8.3
6
10
0.7
400
16
11
8
12
0.8
500
20
13.8
10
15
1.0
off
off
off
off
off
off
I2T off
I2T on
Min. Trip
Time(ms)
Max. Trip
Time(ms)
I2t off
I2t on
Min. Trip
Time(ms)
Max. Trip
Time(ms)
Current Setting(A) (1.15
××
Ir)
Ir = In
××
...
0.4
0.5 0.6 0.7
0.8
0.9 1.0
below 50ms
The function for breaking ground fault current above setting
value after time-delay to protect the circuit from ground fault.
1. Standard current setting Knob-Ig
�Setting range: 0.2/0.3/0.4/0.5/0.6/0.7/0.8//1.0/OFF In
2. Time delay setting Knob-Tg
�Inverse time (I2T On ) : 0.1/0.2/0.3/0.4 Sec
�Definite time (I2T Off) : 0.05/0.1/0.2/0.3/0.4 Sec
3. Ground Fault Operating Characteristic Formula �T = td / I
2
T= Operating time [ms] Td = 1000*Tsd
I = Overload rate (Ground fault current/Standard current)
4. Ground Fault Current = R + S + T + N (Vector Sum)
5. Relay operating current can be adjustable with detailed setting.
6. Relay can operate at instantaneous current through ZSI.
7. Categorize Internal CT Type (Standard Type)note1) and
External CT Type (Separate Order)note2)
Note1) Internal CT Type : Correct relay as the vector sum of
CT on internal R/S/T/N phase
Note2) External CT Type : Install an external CT to be suitable for the
value of ground fault current and then connect to inside of ACB.
In this case, arrange 5A for secondary rating output of CT and set 5A
for standard rating of relays.
1. Ground Fault