Siemens siprotec 7SA522 - Distance Protection with MHO Characteristic (Optional)

2 Functions
92
7SA522 Manual
C53000-G1176-C155-3
2.2.3 Distance protection with MHO characteristic (optional)
The 7SA522 may optionally be provided with polygonal tripping characteristic or with
a MHO circle characteristic, or with both depending on which version was ordered. If
both characteristics are available, they may be selected separately for phase-phase
loops and phase-earth loops. If only the polygonal tripping characteristic is used,
please read Section 2.2.2.
2.2.3.1 Functional Description
Basic Circle One MHO circle is defined for each distance zone, which represents the tripping char-
acteristic of the corresponding zone. In total there are five independent and one addi-
tional controlled zone for each fault impedance loop. The basic shape of a MHO circle
for one zone is shown in Figure 2-25 as an example.
The MHO circle is defined by the line of its diameter which intersects the origin of the
coordinate system and the magnitude of the diameter which corresponds to the im-
pedance Z
r
which determines the reach and its inclination angle set by parameter
1342 R(Z5) Ø-Ø 1A 0.050 .. 600.000 Ω 12.000 Ω R(Z5), Resistance for ph-
ph-faults
5A 0.010 .. 120.000 Ω 2.400 Ω
1343 X(Z5)+ 1A 0.050 .. 600.000 Ω 12.000 Ω X(Z5)+, Reactance for
Forward direction
5A 0.010 .. 120.000 Ω 2.400 Ω
1344 RE(Z5) Ø-E 1A 0.050 .. 600.000 Ω 12.000 Ω RE(Z5), Resistance for ph-e
faults
5A 0.010 .. 120.000 Ω 2.400 Ω
1345 T5 DELAY 0.00 .. 30.00 sec; ∞ 0.90 sec T5 delay
1346 X(Z5)- 1A 0.050 .. 600.000 Ω 4.000 Ω X(Z5)-, Reactance for
Reverse direction
5A 0.010 .. 120.000 Ω 0.800 Ω
1351 Op. mode Z1B Forward
Reverse
Non-Directional
Inactive
Forward Operating mode Z1B (over-
rreach zone)
1352 R(Z1B) Ø-Ø 1A 0.050 .. 600.000 Ω 1.500 Ω R(Z1B), Resistance for ph-
ph-faults
5A 0.010 .. 120.000 Ω 0.300 Ω
1353 X(Z1B) 1A 0.050 .. 600.000 Ω 3.000 Ω X(Z1B), Reactance
5A 0.010 .. 120.000 Ω 0.600 Ω
1354 RE(Z1B) Ø-E 1A 0.050 .. 600.000 Ω 3.000 Ω RE(Z1B), Resistance for
ph-e faults
5A 0.010 .. 120.000 Ω 0.600 Ω
1355 T1B-1phase 0.00 .. 30.00 sec; ∞ 0.00 sec T1B-1phase, delay for
single ph. faults
1356 T1B-multi-phase 0.00 .. 30.00 sec; ∞ 0.00 sec T1B-multi-ph, delay for
multi ph. faults
1357 1st AR -> Z1B NO
YES
YES Z1B enabled before 1st AR
(int. or ext.)
Addr. Parameter C Setting Options Default Setting Comments