Supervising Elements - GE L30 Instruction Manual

5 SETTINGS
a) MAIN MENU

PATH: SETTINGS GROUPED ELEMENTS
 SUPERVISING
 ELEMENTS
b) DISTURBANCE DETECTOR

PATH: SETTINGS GROUPED ELEMENTS
 DISTURBANCE
 DETECTOR
MESSAGE
MESSAGE
MESSAGE
MESSAGE
The disturbance detector (50DD) element is an 87L-dedicated sensitive current disturbance detector that is used to detect
any disturbance on the protected system. This detector is intended for such functions as trip output supervision and starting
oscillography The disturbance detector also signals the 87L function that a disturbance (possible fault) occurred and to
resize the operating window to remove the pre-fault current. It is essential to have the disturbance detector enabled for
applications where the 87L operating time is critical.
If the disturbance detector is used to supervise the operation of the 87L function, it is recommended that the 87L trip ele-
ment be used. The disturbance detector FlexLogic operand must then be assigned to an
50DD SV
The disturbance detector function measures the magnitude of the negative-sequence current (I_2), the magnitude of the
zero-sequence current (I_0), the change in negative-sequence current (ΔI_2), the change in zero-sequence current (ΔI_0),
and the change in positive-sequence current (ΔI_1). The disturbance detector element uses net local current, computed as
a sum of all sources configured in the current differential element, to detect system disturbances.
The adaptive level detector operates as follows:
• When the absolute level increases above 0.12 pu for I_0 or I_2, the adaptive level detector output is active and the
next highest threshold level is increased 8 cycles later from 0.12 to 0.24 pu in steps of 0.02 pu. If the level exceeds
0.24 pu, the current adaptive level detector setting remains at 0.24 pu and the output remains active (as well as the
disturbance detector output) when the measured value remains above the current setting.
GE Multilin
Figure 5–87: AUXILIARY OVERVOLTAGE SCHEME LOGIC

SETTING GROUP 1(6)
 DISTURBANCE
 DETECTOR

SETTING GROUP 1(6)
DD
FUNCTION: Disabled
DD NON-CURRENT SUPV:
Off
DD CONTROL LOGIC:
Off
DD LOGIC SEAL-IN:
Off
DD
EVENTS: Disabled
L30 Line Current Differential System
5.6 GROUPED ELEMENTS

5.6.10 SUPERVISING ELEMENTS


SUPERVISING ELEMENTS
See page 5-195.

SUPERVISING ELEMENTS
Range: Disabled, Enabled
Range: FlexLogic operand
Range: FlexLogic operand
Range: FlexLogic operand
Range: Disabled, Enabled

DISTURBANCE DETECTOR
setting.
87L TRIP SUPV
5-195
5