Schweitzer Engineering Laboratories SEL-421-4 - Table 5.52 Mho Phase-Distance Elements Relay Word Bits

5.81
Date Code 20171021 Instruction Manual SEL-421 Relay
Protection Functions
Mho Phase-Distance Elements
elements and are useful in applications with series compensation. For more infor-
mation on setting relays to protect series-compensated lines, see AG2000-11:
Applying the SEL-321 Relay on Series-Compensated Systems.
NOTE: If the relay is using a remote
data acquisition system, such as TiDL,
the operating times will be delayed by
1.5 ms. Use caution when setting the
relay coordination times to account
for this added delay.
The SEL-421-5 has three independent zones of high-speed mho phase-distance
protection. The high-speed mho phase-distance protection operates for phase-to-
phase, phase-to-phase-to-ground, and three-phase faults. The first three zones of
mho phase-distance protection (Zone 1, Zone 2, and Zone 3) are for high-speed
operation; typical detection time is less than one cycle.
Table 5.52 Mho Phase-Distance Elements Relay Word Bits
Relay Word Bit Description
MAB1 Zone 1 mho A-B phase element
MBC1 Zone 1 mho B-C phase element
MCA1 Zone 1 mho C-A phase element
Z1P Zone 1 phase-distance element
MAB2 Zone 2 mho A-B phase element
MBC2 Zone 2 mho B-C phase element
MCA2 Zone 2 mho C-A phase element
Z2P Zone 2 phase-distance element
MAB3 Zone 3 mho A-B phase element
MBC3 Zone 3 mho B-C phase element
MCA3 Zone 3 mho C-A phase element
Z3P Zone 3 phase-distance element
MAB4 Zone 4 mho A-B phase element
MBC4 Zone 4 mho B-C phase element
MCA4 Zone 4 mho C-A phase element
Z4P Zone 4 phase-distance element
MAB5 Zone 5 mho A-B phase element
MBC5 Zone 5 mho B-C phase element
MCA5 Zone 5 mho C-A phase element
Z5P Zone 5 phase-distance element