GE 869 Instruction Manual page 372

PROTECTION
4–240
SIGNAL INPUT
Range: Positive Impedance 1, Positive Impedance 2
Default: Positive Impedance 1
This setting provides the selection for the positive sequence impedance which is
calculated by terminal side or neutral side CT. Positive sequence impedance 1 is
calculated using 3-phase J1 currents and 3-phase J2 voltages. Positive sequence
impedance 2 is calculated using 3-phase K1 currents and 3-phase J2 voltages.
MHO FORWARD REACH
Range: 0.10 to 500.00 ohms in steps of 0.01 ohms
Default: 2.00 ohms
This setting specifies the forward reach of the mho characteristic. The reach impedance
is entered in secondary ohms. The reach impedance angle is fixed to 90 degrees.
MHO REVERSE REACH
Range: 0.10 to 500.00 ohms in steps of 0.01 ohms
Default: 2.00 ohms
This setting specifies the reverse reach of the mho characteristic. The reach impedance
is entered in secondary ohms. The reach impedance angle is fixed to -90 degrees.
RIGHT BLINDER
Range: 0.10 to 500.00 ohms in steps of 0.01 ohms
Default: 2.00 ohms
This setting defines the right blinder position of the blinder characteristic along with the
resistive axis of the impedance plane, expressed ins secondary ohms. The angular
position of the blinder is adjustable with the use of the BLINDERS RCA setting.
LEFT BLINDER
Range: 0.10 to 500.00 ohms in steps of 0.01 ohms
Default: 2.00 ohms
This setting defines the left blinder position of the blinder characteristic along with the
resistive axis of the impedance plane, expressed ins secondary ohms. The angular
position of the blinder is adjustable with the use of the BLINDERS RCA setting.
BLINDER RCA
Range: 40 to 90° in steps of 1°
Default: 90°
This setting defines the angular position of the left and right blinders.
PICKUP DELAY
Range: 0.000 to 1.000 s in steps of 0.001 s
Default: 0.100 s
This setting should be set to detect the fastest expected unstable power swing and
produce out-of-step tripping in a secure manner. This timer defines the interval that the
impedance locus must spend between the left and right blinders to establish the out-of-
step tripping signal. This time delay must be set shorter than the time required for the
impedance locus to travel between the left and right blinders during the fastest
expected out-of-step. Setting the delay too long can reduce dependability.
869 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 4: SETPOINTS