GE G30 Instruction Manual page 520

INPUTS/OUTPUTS
A contact inputs and outputs are digital signals associated with connections to hard-wired contacts. Wet and dry contacts
are supported.
Upon startup of the relay, the main processor determines from an assessment of the modules installed in the chassis
which contact outputs are available and then presents the settings for only these outputs. Where the contact input is non-
latching, the settings are as shown.
An ID can be assigned to each contact output. The signal that can OPERATE a contact output can be any FlexLogic
operand (virtual output, element state, contact input, or virtual input). An additional FlexLogic operand can be used to
SEAL-IN the relay. Any change of state of a contact output can be logged as an Event if programmed to do so.
For example, the trip circuit current is monitored by providing a current threshold detector in series with some Form-A
contacts (see the trip circuit example in the Digital Elements section). The monitor sets a flag (see the specifications for
Form-A). The name of the FlexLogic operand set by the monitor, consists of the output relay designation, followed by the
name of the flag; for example,
In most breaker control circuits, the trip coil is connected in series with a breaker auxiliary contact used to interrupt current
flow after the breaker has tripped, to prevent damage to the less robust initiating contact. This can be done by monitoring
an auxiliary contact on the breaker which opens when the breaker has tripped, but this scheme is subject to incorrect
operation caused by differences in timing between breaker auxiliary contact change-of-state and interruption of current in
the trip circuit. The most dependable protection of the initiating contact is provided by directly measuring current in the
tripping circuit, and using this parameter to control resetting of the initiating relay. This scheme is often called trip seal-in.
This can be realized using the
CONTACT OUTPUT H1 ID
OUTPUT H1 OPERATE
OUTPUT H1 SEAL-IN
CONTACT OUTPUT H1 EVENTS
5
5.9.3.2 Latching outputs
SETTINGS  INPUTS/OUTPUTS  CONTACT OUTPUTS  CONTACT OUTPUT H1a
 CONTACT OUTPUT H1a

5-306
Cont OP 1 IOn.
FlexLogic operand to seal-in the contact output as follows:
Cont OP 1 IOn
: "Cont Op
1"
: any suitable FlexLogic operand
: "Cont Op 1
IOn"
: "Enabled"
Figure 5-172: Contact input/output module type 6A contact 1 logic
OUTPUT H1a ID

L-Cont Op 1
OUTPUT H1a OPERATE:

Off
OUTPUT H1a RESET:

Off
OUTPUT H1a TYPE:

Operate-dominant
OUTPUT H1a EVENTS:

Disabled
Range: up to 20 alphanumeric characters
Range: FlexLogic operand
Range: FlexLogic operand
Range: Operate-dominant, Reset-dominant
Range: Disabled, Enabled
G30 GENERATOR PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 5: SETTINGS