S3 Logic Inputs; Overview - GE 750 Instruction Manual

S3 Logic Inputs

Table 5–1: FlexCurve™ Trip Times
Pickup Trip Time
(I/I ) (ms)
pu
1.03
1.05
1.10
1.20
1.30
1.40
1.50
1.60
1.70
1.80
1.90
2.00
2.10
2.20
2.30
2.40
2.50
2.60
2.70
2.80

Overview

GE Multilin
Two programmable FlexCurves™ can be stored in the relay. These can be used for
time overcurrent protection in the same way as ANSI, IAC, and IEC curves. The
FlexCurve™ has setpoints for entering trip times at the following current levels:
1.03, 1.05, 1.1 to 6.0 in steps of 0.1, and 6.5 to 20.0 in steps of 0.5. The relay
converts these points to a continuous curve by linear interpolation.
The following table shows all the pickup levels for which a trip time must be entered.
Pickup Trip Time
(I/I ) (ms)
pu
2.90
3.00
3.10
3.20
3.30
3.40
3.50
3.60
3.70
3.80
3.90
4.00
4.10
4.20
4.30
4.40
4.50
4.60
4.70
4.80
S3 Logic Inputs
The 750/760 relay has twenty (20) logic inputs which can be used to operate a
variety of logic functions for circuit breaker control, external trips, blocking of
protection elements, etc. The relay has 'contact inputs' and 'virtual inputs' that are
combined in a form of programmable logic to facilitate the implementation of
various schemes.
The relay has 14 rear terminal contact inputs. These contacts can be either wet or
dry (see Logic Inputs on page 3–13 for typical wiring of the logic input contacts).
External contacts are either open or closed and are de-bounced for one power
frequency cycle to prevent false operation from induced voltage. Because of
debouncing, momentary contacts must have a minimum dwell time greater than
one power frequency cycle.
The relay also has twenty (20) virtual inputs which are analogous to software
switches. They allow all the functionality of logic inputs to be invoked via serial
communications or from the front panel. This has the following advantages over
contact inputs only:
• The number of logic inputs can be increased without introducing additional
hardware.
• Logic functions can be invoked from a remote location over a single RS485
communications channel.
http://www.GEmultilin.com
Feeder Management Relay
Pickup Trip Time
(I/I ) (ms)
pu
4.90
5.00
5.10
5.20
5.30
5.40
5.50
5.60
5.70
5.80
5.90
6.00
6.50
7.00
7.50
8.00
8.50
9.00
9.50
10.0
750/760
Pickup Trip Time
(I/I ) (ms)
pu
10.5
11.0
11.5
12.0
12.5
13.0
13.5
14.0
14.5
15.0
15.5
16.0
16.5
17.0
17.5
18.0
18.5
19.0
19.5
20.0
5–19