GE D90 Plus Instruction Manual page 393

Line distance protection system

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Table of Contents

CHAPTER 7: PROTECTION

Composite recloser curve example

LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL

Figure 321: Recloser curve initialization

The multiplier and adder settings affect the curve portion of the characteristic and not the

MRT and HCT settings. The HCT settings override the MRT settings for multiples of pickup

greater than the HCT ratio.

A composite curve can be created from the GE_111 standard with MRT = 200 ms and HCT

initially disabled and then enabled at eight times pickup with an operating time of 30 ms.

At approximately four times pickup, the curve operating time is equal to the MRT and from

then onwards the operating time remains at 200 ms (see figure).

Figure 322: Composite recloser curve with HCT disabled

With the HCT feature enabled, the operating time reduces to 30 ms for pickup multiples

exceeding eight times pickup.

CONTROL ELEMENTS