MTB: Mask for Trip with Block input Deasserted
The relay closes the TRIP output when the Block Trip (BT) input is not asserted and elements
selected in this mask pick up. BT input assertion serves as an external qualifying condition.
As with the MTU logic mask, it is not advisable to mask nondirectional elements in the MTB
logic mask unless your application permits.
Mask for Trip Block (MTB)
Z1P Z1G Z2PT Z2GT Z3 Z3T 3P21 32Q
0
0
0
0
0
0
0
0
67N 51NP 51NT 50NG 50P 50H IN1
REJO
0
0
0
0
0
0
0
0
LOP 52BT 27S 27P 59S 59P SSC
VSC
0
0
0
0
0
0
0
0
Event Report
Hexadecimal Code
00
00
00
The example mask for block tripping contains all zeros because the relay is not being used in
a blocking scheme.
MTO: Mask for Trip with the 52BT Element Asserted
The relay closes the TRIP output when the 52BT bit is asserted and elements selected in this
mask pick up. The 52BT bit is a time delayed, inverted follower of the 52A input (see
switch-onto-fault logic explanation for a detailed timing explanation of the 52BT bit). This
tripping mask differs from the MTU, MPT, and MTB tripping masks because it is acceptable
to mask sensitive nondirectional elements into MTO in certain applications. Such masking is
advisable except in applications where the line breaker is closed into a line energized from the
remote terminal (i.e., synchronized closures).
Typical bits set in the MTO logic mask include Zone 1 instantaneous elements (Z1P, Z1G,
and 67N), the non-directional high-set overcurrent element (50H), and Zone 3 instantaneous
elements (Z3).
Note:
Never mask the 52BT bit into the MTO logic mask. This causes an undesirable
seal-in of TRIP output contacts when the 52BT bit is asserted.
Mask for Trip Breaker Open (MTO)
Z1P Z1G Z2PT Z2GT Z3 Z3T 3P21 32Q
1
1
1
1
1
1
0
0
67N 51NP 51NT 50NG 50P 50H IN1
REJO
1
0
1
0
0
1
0
0
LOP 52BT 27S 27P 59S 59P SSC
VSC
0
0
0
0
0
0
0
0
Event Report
Hexadecimal Code
FC
A4
00
Date Code 920508
Applications
SEL-221F, -1 Instruction Manual
5-33
Summary of Contents for SEL-221F
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Page 110: ...Example Event Report 2 4 12 Event Reporting SEL 221F 1 Instruction Manual Date Code 930830 ...
Page 158: ...SETTINGS SHEET FOR SEL 221F RELAY PAGE 2 OF 6 DATE Date Code 921110 ...
Page 160: ...SETTINGS SHEET PAGE 4 OF 6 FOR SEL 221F RELAY DATE Date Code 930601 ...
Page 161: ...SETTINGS SHEET PAGE 5 OF 6 FOR SEL 221F RELAY DATE Date Code 961208 ...
Page 229: ...SEL 200 Series Relay Main Board Troubleshooting Test Points and Jumper Locations ...