Negative Sequence Current - GE Multilin G650 Manual

5.4 PROTECTION ELEMENTS
The Negative sequence menu incorporates the following elements:
• Negative sequence time overcurrent (51-2)
• Negative sequence instantaneous overcurrent (50-2)
• Generator unbalance (46)
5.4.8.1 NEGATIVE SEQUENCE OVERCURRENT ELEMENT (51-2)
Negative Sequence TOC is an overcurrent protection element that uses the fundamental phasor of the negative sequence
current as input magnitude, calculated from the phase currents. This element can be used for detecting load unbalance in
the system, and for open phase conditions (fallen or broken conductor). The trip can be time delayed by a curve selectable
by setting. The reset can be instantaneous or linear.
Table 5–61: NEGATIVE SEQUENCE TOC ELEMENT SETTINGS
SETPOINT > PROTECTION ELEMENTS > NEGATIVE SEQUENCE CURRENT > NEGATIVE SEQUENCE TOC >
NEGATIVE SEQUENCE TOC 1> NEGATIVE SEQUENCE TOC 2 > NEGATIVE SEQUENCE TOC 3
SETTING DESCRIPTION
Function permission
Pickup level
Curve shape
Time Dial
Reset type
5
Snapshot Event generation
The snapshot event setting enables or disables the snapshot event generation for this element.
5.4.8.2 NEGATIVE SEQUENCE INSTANTANEOUS OVERCURRENT ELEMENT (50-2)
Negative Sequence IOC is an overcurrent protection element that uses the fundamental phasor of the negative sequence
current as input magnitude, calculated from the phase currents. This element can be used for detecting load unbalance in
the system, and for open phase conditions (fallen or broken conductor). The trip time can be selected as instantaneous
timed, with the timer selectable between 0.00 and 900 seconds. The element incorporates a reset time selectable between
0 and 900 seconds.
Table 5–62: NEGATIVE SEQUENCE IOC ELEMENT SETTINGS
SETPOINT > PROTECTION ELEMENTS > NEGATIVE SEQUENCE CURRENT > NEGATIVE SEQUENCE IOC >
NEGATIVE SEQUENCE IOC 1> NEGATIVE SEQUENCE IOC 2 > NEGATIVE SEQUENCE IOC 3
SETTING DESCRIPTION
Function permission
Pickup level
Trip time
Reset time
Snapshot Event generation
The snapshot event setting enables or disables the snapshot event generation for this element.
5-60
NAME DEFAULT VALUE
Function DISABLED
Pickup Level 1.00
Curve IEEE Ext Inv
TD Multiplier 1.00
Reset INSTANTANEOUS
Snapshot Events ENABLED
NAME DEFAULT VALUE
Function DISABLED
Pickup Level 30.00
Trip delay 0.00 s
Reset delay 0.00 s
Snapshot Events ENABLED
G650 Generator Protection & Control System

5.4.8 NEGATIVE SEQUENCE CURRENT

STEP RANGE
N/A [DISABLED – ENABLED]
0.01 A [0.05 : 160.00]
N/A [See list of curves]
0.01 s [0.00 : 900.00]
N/A [INSTANTANEOUS – LINEAR]
N/A [DISABLED – ENABLED]
STEP RANGE
N/A [DISABLED – ENABLED]
0.01 A [0.05 : 160.00]
0.01 s [0.00 : 900.00]
0.01 s [0.00 : 900.00]
N/A [DISABLED – ENABLED]
5 SETTINGS
or
GEK-113285A