Sel 411L - Communications-Assisted Tripping Logic; Figure 3.147 Required Zone Directional Settings; Table 3.116 ECOMM Setting

P.3.220
SEL-411L Relay Protection Manual Date Code 20151029
Protection Functions
Communications-Assisted Tripping Logic
Communications-Assisted Tripping Logic
Communications-assisted tripping schemes provide unit protection for
transmission lines without any need for external coordination devices. The
relay includes the following five schemes.
➤ POTT—Permissive-overreaching transfer trip
➤ POTT2—Two-channel permissive overreaching transfer trip
➤ POTT3—Phase-segregated permissive overreaching
transfer trip
➤ DCUB—Directional comparison unblocking
➤ DCB—Directional comparison blocking
All of these schemes work in both two-terminal and three-terminal line
applications. For the DCUB scheme, you have separate settings choices for
these applications (ECOMM equals DCUB1 or DCUB2) because of unique
DCUB logic considerations.
You must set Zone 3 reverse-looking (DIR3 equals R) for all three schemes.
Figure 3.147 Required Zone Directional Settings
Table 3.116 ECOMM Setting
Setting Description Range
Default
(5 A)
ECOMM Communications-assisted tripping N, DCB, POTT,
POTT2, POTT3,
DCUB1, DCUB2
N
Relay
BK1
Transmission Line
Bus S
BK2
Relay
Comm.
Equip
Comm.
Equip
TX
RX
TX
RX
Bus R
Zone 3 (R)
Zone 1 (R)
Zone 2 (R)
Zone 3 (S)
Zone 1 (S)
Zone 2 (S)