Functions
2.2 Phase Comparison Protection and Ground Differential Protection
SIPROTEC, 7SD80, Manual
E50417-G1140-C474-A1, Release date 09.2011
54
Pickup Logic
The dynamic and the static element pick up independently of each other selectively for each phase.
To prevent tripping during an energization, a separate dynamic switch-on threshold 87L Idyn close> is
used.
The pickup is maintained over 2 measuring cycles. After the 2 measuring cycles have expired, the dynamic
sign comparison is blocked.
If the pickup is successful, an internal pickup signal is transmitted to the other device.
The element Idyn is blocked if the frequency deviates by more than 10 % from the rated frequency.
The function is blocked if the communication between the two devices at the ends of the protected object fails
for more than two measuring cycles.
This function can also be blocked via binary input „>87L block“.
The following figure shows the formation of the phase-specific pickup of the elements 87L Isteady> and 87L
Idyn>.
Figure 2-5 Logic diagram of the phase comparison protection, phase-selective generation of the Istat and Idyn signal
To Next Page
Loading...
Need help?
General
