Schweitzer Engineering Laboratories SEL-311C - Additional Distance Element Supervision; Figure 3.15 Zone 1 Extension Logic; Table 3.4 Zone 1 Settings; Zone 1 Extension

3.19
Date Code 20060320 Instruction Manual SEL-311C Relay
Distance, Out-of-Step, Overcurrent, Voltage, Synchronism Check, and Frequency Elements
Distance Element Operating Time Curves at Nominal Frequency
Additional Distance
Element Supervision
The SEL-311C uses Relay Word bit VPOLV for positive-sequence memory
supervision of mho and quadrilateral characteristics. VPOLV asserts when the
memorized positive-sequence polarizing voltage is greater than 1 Volt.
Phase and ground distance elements are supervised with Fault Identification
Selection (FIDS) logic. This logic identifies the faulted phase(s) for all faults
involving ground by comparing the angle between I0 and I2. For example,
when FIDS selects A-phase, FSA asserts and enables A phase ground distance
elements and CB-phase distance elements. Distance elements BG, CG, AB,
and CA are blocked.
Zone 1 Extension
See Figure 3.15. When enabled, this logic modifies the reach of all Zone 1
distance elements by multiplier setting Z1EXTM once all three poles are
closed for Z1EXTD time. All Zone 1 reaches retreat to their set reach when
3PO asserts.
The Zone 1 reaches cannot be extended if any of the following elements are
asserted: M1P–M2P, Z1G–Z2G, 51G, or 51Q.
q From Figure 3.26; w from Figure 3.25; e from Figure 3.4; r from Figure 3.7;
t from Figure 3.5; y from Figure 3.8; u from Figure 5.3; i from Figure 3.10.
Figure 3.15 Zone 1 Extension Logic
Table 3.4 Zone 1 Settings
Description Setting Setting Recommendation
Enable Zone 1 Extension EZ1EXT
Zone 1 Extension Delay Z1EXTD Sets the minimum time the breaker must be
closed before extending the Zone 1 reach.
Zone 1 Extension Multiplier Z1EXTM Sets the scalar by which all Zone 1
reaches are multiplied. Z1EXTM times
the Zone 1 distance setting is never set
less than the Zone 1 distance setting or greater
than 90 percent of Zone 2 reach.
Z1P < (Z1EXTM • Z1P) < (0.9 • Z2P) and
Z1MG < (Z1EXTM • ZMG) < (0.9 • Z2MG)
and X1G < (Z1EXTM • X1G) < (0.9 • X2G)
must all be true or the SEL-311C will
not allow the Z1EXTM setting.
EZ1EXT = N
(Setting)
q 51Q
0
Z1EXTD
S
R
Q Z1X
w 51G
e M1P
r Z1G
t M2P
y Z2G
u 3PO
Z1X
0
1
X1
(See e, r, and i)
1.0
Z1EXTM