Schweitzer Engineering Laboratories SEL-351-5, Instruction Manual

Page: 229 / 706

5.27
Date Code 20070117
Instruction Manual SEL-351-5, -6, -7 Relay
Trip and Target Logic
Directional Comparison Blocking (DCB) Logic
Z3XD—Zone (Level) 3 Reverse Dropout Extension
Current-reversal guard dropout timer—typically set at 5 cycles.
BTXD—Block Trip Receive Extension
Sets reset time of block trip received condition (BTX) after the reset of block
trip input BT.
67P2SD, 67N2SD, 67G2SD, 67Q2SD—Level 2 Short Delay
Carrier coordination delays for the output of Level 2 overreaching overcurrent
elements 67P2S, 67N2S, 67G2S, and 67Q2S, respectively—typically set at
1 cycle.
Logic Outputs
The following logic outputs can be tested by assigning them to output
contacts. See
Output Contacts on page 7.32 for more information on output
contacts.
DSTRT—Directional Carrier Start
Program an output contact for directional carrier start. For example, SEL
OGIC
control equation setting OUT105 is set:
OUT105 =
DSTRT
Output contact OUT105 drives a communications equipment transmitter input
in a two-terminal line application (see Figure 5.15 ).
In a three-terminal line scheme, output contact
OUT107
is set the same as
OUT105
(see Figure 5.16 ):
OUT107 =
DSTRT
DSTART includes current reversal guard logic.
NSTRT—Nondirectional Carrier Start
Program an output contact to include nondirectional carrier start, in addition
to directional start. For example, SEL
OGIC
control equation setting
OUT105
is
set:
OUT105 =
DSTRT + NSTRT
Output contact OUT105 drives a communications equipment transmitter input
in a two-terminal line application (see Figure 5.15 ).
In a three-terminal line scheme, output contact
OUT107
is set the same as
OUT105
(see Figure 5.16 ):
OUT107 =
DSTRT + NSTRT
STOP—Stop Carrier
Program to an output contact to stop carrier. For example, SEL
OGIC
control
equation setting OUT106 is set:
OUT106 = STOP
Output contact
OUT106
drives a communications equipment transmitter input
in a two-terminal line application (see Figure 5.15 ).