Functions
6-617SA522 Manual
C53000-G1176-C119-2
The zones and phases of such a valid fault detection are alarmed, e.g. Dis. Z1 L1E for
zone Z1 and phase L1. The zone logic (refer to Sub-section 6.2.5) and supplementary
functions (e.g. teleprotection logic, Sub-section 6.4.1) process these signals further.
In total, the following zones are available:
Independent zones:
• 1st Zone (fast tripping zone) Z1 with =5=; may be delayed by 7SKDVH and
7PXOWLSKDVH
• 2nd Zone (back-up zone) Z2 with =5=; may be delayed by 7SKDVH and
7PXOWLSKDVH
• 3rd Zone (back-up zone) Z3 with =5=; may be delayed by 7'(/$<
• 4th Zone (back-up zone) Z4 with =5=; may be delayed by 7'(/$<
• 5th Zone (back-up zone) Z5 with =5=; may be delayed by 7'(/$<
Dependant (controlled) Zone:
• Overreaching zone Z1B with =5=%; may be delayed by 7%SKDVH and / or
7%PXOWLSKDVH.
6.2.4.2 Applying the Function Parameter Settings
The function parameters for the MHO circle characteristic only apply if during the con-
figuration of the scope of functions (Section 5.1) the 0+2 circle was selected for
phase–phase measurement (address ) and/or phase–earth measurement (ad-
dress ).
Grading coordina-
tion chart
It is recommended to initially create a grading coordination chart for the entire galvan-
ically interconnected system. This diagram should reflect the line lengths with their pri-
mary impedance Z in Ω/phase. For the reach of the distance zones, the impedances
Z are the deciding quantities.
The first zone Z1 is usually set to cover 85 % of the protected line without any trip time
delay (i.e. T1 = 0.00 s). The protection clears faults in this range without additional
time delay, i.e. the tripping time is the relay basic operating time.
The tripping time of the higher zones is sequentially increased by one time grading
margin. The grading margin must take into account the circuit breaker operating time
including the spread of this time, the resetting time of the protection equipment as well
as the spread of the protection delay timers. Typical values are 0.2 s to 0.4 s. The
reach is selected to cover up to approximately 80 % of the zone with the same set time
delay on the shortest neighbouring feeder.
When entering the relay parameters with a personal computer and DIGSI
®
4 it can be
selected whether the settings are entered as primary or secondary values.
In the case of parameterization with secondary quantities, the values derived from the
grading coordination chart must be converted to the secondary side of the current and
voltage transformers. In general the following applies:
Z
secondary
Current transformer ratio
Voltage transformer ratio
-----------------------------------------------------------------------
Z
primary
⋅=
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