GE L60 Instruction Manual page 342

GROUPED ELEMENTS CHAPTER 5: SETTINGS
— This setting specifies the more stringent stability angle allowing the scheme to trip safely on
87PC ENHANCED STAB ANGLE
the first coincidence. This setting applies only if the mode is set to "Enhanced." This setting is typically
87PC TRIP SECURITY
30° to 40° higher than the regular stability angle specified by the setting.
87PC STABILITY ANGLE
The figure illustrates enhanced trip security. In part a) of the figure, tripping occurs at the first coincidence if the integrator
exceeds the enhanced stability angle setting. In part b), tripping occurs at the second coincidence if at the first coincidence
integrator exceeded the stability angle setting but did not reach the enhanced stability angle setting.
Figure 5-85: Enhanced trip security
5
— This setting specifies a pickup delay for the phase comparison element. This delays the start of the
87PC PICKUP DELAY
coincidence detection by specified time. It does not affect start of the signal transmittal to the remote terminal.
— This setting selects a FlexLogic operand that is used to stop signal transmittal to the remote terminal. This
87PC STOP TX
can be used in blocking schemes to accelerate tripping at the remote end and in tripping schemes to prevent tripping at
the remote end, if desirable.
— This setting specifies a time delay to prolong signal transmission to the remote end after FDL drops
87PC TX RESET DELAY
off and is recommended for blocking schemes only. If mixed current is greater than 0.02 pu, then square pulses are
transmitted. If mixed current is less than 0.02 pu, then continuous blocking signal are transmitted for blocking schemes.
— This setting is used to seal-in the output phase comparison element after operating by the time
87PC RESET DELAY
defined by this setting. A value of 30 ms or higher is recommended. A value of 0 ms operates the element during integrated
coincidence only, meaning that the 87PC OP output operand is set and reset on every cycle.
— This setting increases sensitivity during and after the clearing of an external fault and prevents
87PC TRANS BLOCK PICKUP
false tripping during transient current intervals. If a pickup delay is used, the this setting must be increased by the time
specified in the setting.
87PC PICKUP DELAY
— Resets transient blocking and allows tripping.
87PC TRANS BLOCK RESET
— This setting is applicable to the 2TL-UB-DPC-2FC scheme only. If a loss of carrier is
87PC CHNL LOSS TRIP WINDOW
detected in the course of the fault, a trip is allowed for the time defined by this setting (default value is 0). The trip is blocked
after the expiration of this time window.
and — These settings allow decreasing of the tripping time by up
87PC HIGH-SPEED CONTACT 1 87PC HIGH-SPEED CONTACT 2
to one-quarter of the power cycle by bypassing FlexLogic execution and sending trip command directly from the 87PC
function to the contact output. These setting are used for breaker 1 and 2 (if used) trip coil connections.
5-174 L60 LINE PHASE COMPARISON SYSTEM – INSTRUCTION MANUAL