Supervising Elements - GE L30 Instruction Manual

GROUPED ELEMENTS

5.7.10 Supervising elements

5.7.10.1 Menu
SETTINGS  GROUPED ELEMENTS  SETTING GROUP 1(6)  SUPERVISING ELEMENTS
 SUPERVISING
 ELEMENTS
5
5.7.10.2 Disturbance detector
SETTINGS  GROUPED ELEMENTS  SETTING GROUP 1(6)  SUPERVISING ELEMENTS  DISTURBANCE
DETECTOR
 DISTURBANCE
 DETECTOR
The disturbance detector (50DD) element is an 87L-dedicated sensitive current disturbance detector that is used to detect
any disturbance on the protected system. It 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.
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 (DI_2), the change in zero-sequence current (DI_0),
and the change in positive-sequence current (DI_1). The disturbance detector element uses net local current, computed as
5-256
Figure 5-134: Auxiliary overvoltage logic
 DISTURBANCE

 DETECTOR
DD

FUNCTION: Disabled
DD NON-CURRENT SUPV:

Off
DD CONTROL LOGIC:

Off
DD LOGIC SEAL-IN:

Off
DD SEAL-IN BY 87LG:

Disabled
DD VOLTAGE SUPV:

Disabled
DD

EVENTS: Disabled
See below
Range: Disabled, Enabled
Range: FlexLogic operand
Range: FlexLogic operand
Range: FlexLogic operand
Range: Disabled, Enabled
Range: Disabled, Enabled
Range: Disabled, Enabled
L30 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL
CHAPTER 5: SETTINGS