GE D90 Plus Instruction Manual page 209

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 disables 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 can 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 following figure shows phase distance operation scheme logic for zone 1.

Figure 175: Phase distance zone 1 operation logic

The following figure shows the phase distance operation scheme logic for zone 2. The logic

is analogous for zones 3 through 5.

GROUPED PROTECTION ELEMENTS

Voltage Level