GE D90 Plus Instruction Manual page 205

Line distance protection system

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CHAPTER 7: PROTECTION

LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL

The use of dynamic reach control by selection of a non-zero value for the

setting will disable the subcycle operating time for that particular zone.

Range: 0.000 to 65.535 seconds in steps of 0.001

Default: 0.000 seconds

This setting allows the user to delay operation of the distance elements and implement

stepped distance protection. The distance element timers for zones 2 through 5 apply a

short dropout delay to cope with faults located close to the zone boundary when small

oscillations in the voltages or currents could inadvertently reset the timer. Zone 1 does

not need any drop out delay since it is sealed-in by the presence of current.

Range: any FlexLogic™ operand

Default: OFF

This setting enables the user to select a FlexLogic™ operand to block a given distance

element. VT fuse fail detection is one of the applications for this setting.

Range: Enabled, Disabled

Default: Enabled

This setting enables and disables the logging of phase distance events in the sequence

of events recorder.

The phase distance operation scheme logic for zone 1 is shown below.

Figure 171: Phase distance zone 1 operation scheme logic

The phase distance operation scheme logic for zone 2 is shown below. The logic is

analogous for zones 3 through 5.

GROUPED PROTECTION ELEMENTS

Voltage Level