5-314
L90 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL
GROUPED ELEMENTS
CHAPTER 5: SETTINGS
5
The following settings are available.
COMPENSATED OV Zc MAG
— This setting specifies the magnitude of the impedance Z
C
in secondary ohms. Set it to half the
positive-sequence series impedance of the line. Alternately, if the positive-sequence charging currents and local and
remote voltages are known, then this value can be calculated from equation above.
COMPENSATED OV Zc ANG
— This setting specifies the angle of the impedance Z
C
in degrees.
COMPENSATED OV I_1max
— This setting specifies the maximum expected positive-sequence line current for which a
remote overvoltage is anticipated.
COMPENSATED OV STG1 PKP
,
COMPENSATED OV STG2 PKP
,
COMPENSATED OV STG3 PKP
— These settings specify the pickup level
for each of the three stages. If any stage is set with no intentional time delay, then set the pickup setting 15% above the
anticipated steady state overvoltage to prevent an operation during line energization. A stage that is not used can be set
to its maximum setting value (3.000 pu) to effectively disable it.
COMPENSATED OV STG1 DELAY
,
COMPENSATED OV STG2 DELAY
,
COMPENSATED OV STG3 DELAY
— These settings specify the time
delay for each of the three stages in seconds.
Figure 5-179: Compensated overvoltage logic
5.7.15 Supervising elements
5.7.15.1 Menu
SETTINGS
GROUPED ELEMENTS
SETTING GROUP 1(6)
SUPERVISING ELEMENTS
SUPERVISING
ELEMENTS
DISTURBANCE
DETECTOR
See below
87L TRIP