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Functions
2.5 Distance Protection
Figure 2-62
Recommended setting for 1607 Zone Reduction (this graphic applies for overhead lines with a line angle
of more than 60°. A smaller setting may be chosen for cables or protected objects with a smaller angle)
The first step to determine the setting for 1607 Zone Reduction is to determine the maximum load angle for
normal operation (by computer simulation). If this information is not available, a value of about 20° can be
assumed for Western Europe. For other regions with less closely meshed systems, larger angles may have to
be chosen. The next step is to select from Figure 2-62 the curve that matches the load angle. With the set ratio
R1/X1 (zone Z1 polygon) the appropriate setting for 1607 Zone Reduction is then determined.
Example:
With a load angle of 20° and a setting R/X = 2.5 (R1 = 25 Ω, X1 = 10 Ω), a setting of 10° is adequate for 1607
Zone Reduction.
Different delay times can be set for single- and multiple-phase faults in the first zone: T1-1phase (Address
1605) and T1-multi-phase (address 1606). The first zone is normally set to operate without additional time
delay.
For the remaining zones the following correspondingly applies:
X(Z2) (address 1613), R(Z2) Ø-Ø (address 1612), RE(Z2) Ø-E (address 1614);
X(Z3) (address 1623), R(Z3) Ø-Ø (address 1622), RE(Z3) Ø-E (address 1624);
X(Z4) (address 1633), R(Z4) Ø-Ø (address 1632), RE(Z4) Ø-E (address 1634);
X(Z5)+ (address 1643) for forward direction, X(Z5)- (address 1646) for reverse direction, R(Z5) Ø-Ø
(address 1642), RE(Z5) Ø-E (address 1644);
X(Z6)+ (address 1663) for forward direction, X(Z6)- (address 1666) for reverse direction, R(Z6) Ø-Ø
(address 1662), RE(Z6) Ø-E (address 1664).
For the second zone, it is also possible to set separate delay times for single-phase and multi-phase faults. In
general, the delay times are set the same. If stability problems are expected during multi-phase faults, a shorter
delay time could be considered for T2-multi-phase (address 1616) while tolerating a longer delay time for
single-phase faults with T2-1phase (address 1615).
The zone timers for the remaining zones are set with the parameters T3 DELAY (address 1625), T4 DELAY
(address 1635), T5 DELAY (address 1645), and T6 DELAY (address 1665).
158
SIPROTEC, 7SD5, Manual
C53000-G1176-C169-5, Release date 02.2011
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