Table of Contents
Advertisement
1MRK 502 071-UUS A
Generator protection REG670 2.2 ANSI and Injection equipment REX060, REX061, REX062
Application manual
10
tfunc1
n
tfunc2 n
0.01
10
IEC05000204 V2 EN-US
Figure 175:
Fault time with maintained selectivity
The operation time can be set individually for each overcurrent protection.
To assure selectivity between different protection functions in the radial network, there
has to be a minimum time difference Dt between the time delays of two protections. To
determine the shortest possible time difference, the operation time of the protection, the
breaker opening time and the protection resetting time must be known. These time
delays can vary significantly between different protective equipment. The following
time delays can be estimated:
Protection operation
15-60 ms
time:
Protection resetting time:
15-60 ms
Breaker opening time:
20-120 ms
Time-current curves
Str
n
Fault Current
Section 9
Current protection
10000
en05000204.ai
357
Advertisement
Table of Contents
