1. Set OperMode to 1231c
When a cross-country fault has been detected the trip is made according to a chosen
priority: OperMode.
This setting shall be identical for all distance protections in the system. In this case
a cyclic order is used: A– B– C– A.
Setting OperMode: 1231c
2. Set PU27PN to 70 %
The setting PU27PN is used to identify faulted phases. The setting shall be less than
the lowest possible voltage at normal operation. The default value 70 % of VBase is
recommended.
Setting PU27PN to 70 %
3. Set PU27PP to 40 %
The setting PU27PP is used in the logic to evaluate if a fault exists in two or more
phases. The setting must be chosen so that pick-up at phase-to-phase fault in another
fault loop is avoided. The default value 40 % of VBase is recommended.
Setting PU27PP to 40 %
4. Set 3V0PU to 20 %
The setting 3V0PU is used in the logic to evaluate if a phase-to-ground fault exists.
The setting must be chosen so that pick-up at unfaulted conditions is avoided. The
default value 20 % of VBase is recommended.
5. Set Pickup_N to 7 % (70 A)
The setting Pickup_N is used in the logic to evaluate if a cross-country fault exists.
The setting must be chosen larger than the maximum residual current out on the line
at single phase-to-ground fault. In case of a single phase-to-ground fault out on the
protected line the fault current will be according to the figure
34: 3I
0line
≥ 25 + j50.
The setting ≥ 56 · 1.25 = 70 A is proposed.
Section 3 1MRK 506 334-UUS A
REL650 setting examples
84
Application manual
To Next Page
Loading...
