GE L90 Instruction Manual page 482

GROUPED ELEMENTS
DD CONTROL LOGIC
single breaker pole being open that leads to unbalanced load current in single-pole tripping schemes. Breaker auxiliary
contact can be used for such a scheme.
— Used to maintain disturbance detector output,
DD LOGIC SEAL-IN
fault and low level time overcurrent fault, whenever the disturbance detector might reset.
chosen FlexLogic operand resets.
DD SEAL-IN BY 87LG
whenever the
50DD SV
operand resets.
— Used to enable the voltage-based disturbance detector for such applications as the weak condition
DD VOLTAGE SUPV
exists at one terminal, where the weak-infeed current is not able to trigger the current-based disturbance detector. The
voltage signals used for this detector are taken from the source assigned with the
— This setting can be disabled when the disturbance detector element responds to any current disturbance on
DD EVENTS
the system that results in filling the events buffer and possible loss of valuable data.
5
5-296
— Used to prevent operation of I_0 and I_2 logic of disturbance detector during conditions such as
— Used to seal-in the disturbance detector output,
might reset before 87LG time delay elapses.
SV, for such conditions as balanced three-phase
50DD
50DD SV
87LG, especially for the 87LG element
50DD SV
is maintained until the
50DD SV 87LG
CURRENT DIFF SIGNAL SOURCE 1
L90 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL
CHAPTER 5: SETTINGS
is maintained until the
87L DIFF PKP G
setting.