Table 128. Rotor earth-fault protection, injection method (MREFPTOC)
Characteristic
Value
Operation accuracy
Depending on the frequency of the current measured: f
n
±2 Hz
±1.5% of the set value or ±0.002 × I
n
Start time
1)2)
Minimum
Typical
Maximum
I
Fault
= 1.2 × set
Start value
30 ms
34 ms
38 ms
Reset time
<50 ms
Reset ratio
Typically 0.96
Retardation time
<50 ms
Operate time accuracy
±1.0% of the set value of ±20 ms
Suppression of harmonics
-50 dB at f = n × f
n
, where n = 2, 3, 4, 5,…
1)
Current before fault = 0.0 × I
n
, f
n
= 50 Hz, earth-fault current with nominal frequency injected from random phase angle, results based on statistical distribution of 1000 measurements
2)
Includes the delay of the signal output contact
Table 129. Rotor earth-fault protection, injection method (MREFPTOC) main settings
Parameter
Function
Value (Range)
Step
Operate start value
MREFPTOC
0.010...2.000 × I
n
0.001
Alarm start value
MREFPTOC
0.010...2.000 × I
n
0.001
Operate delay time
MREFPTOC
40...20000 ms
1
Alarm delay time
MREFPTOC
40...200000 ms
1
Table 130. High-impedance or flux-balance based differential protection (MHZPDIF)
Characteristic
Value
Operation accuracy
Depending on the frequency of the measured current: f
n
±2 Hz
±1.5% of the set value or 0.002 × I
n
Start time
1)2)
Minimum
Typical
Maximum
I
Fault
= 2.0 × set
Start Value (one
phase fault)
13 ms
17 ms
21 ms
I
Fault
= 2.0 × set
Start Value (three
phases fault)
11 ms
14 ms
17 ms
Reset time
<40 ms
Reset ratio
Typically 0.96
Retardation time
<35 ms
Operate time accuracy in definite time mode
±1.0% of the set value of ±20 ms
1)
Measurement mode = “Peak-to-Peak”, current before fault = 0.0 × I
n
, f
n
= 50 Hz, fault current with nominal frequency injected from random phase angle, results based on statistical
distribution of 1000 measurements
2)
Includes the delay of the signal output contact
Table 131. High-impedance or flux-balance based differential protection (MHZPDIF) main settings
Parameter
Function
Value (Range)
Step
Operate value
MHZPDIF
0.5...50.0 %I
n
0.1
Minimum operate time
MHZPDIF
20...300000 ms
10
1MRS759144 A
REX640
Product version: 1
70
ABB
Summary of Contents for RELION REX640
Page 1: ...RELION PROTECTION AND CONTROL REX640 Product Guide...
Page 128: ...128...
Page 129: ......
Page 130: ......
Page 131: ......
