Fault Locator; Description - GE L30 Instruction Manual

FAULT LOCATOR

CHAPTER 10: THEORY OF OPERATION
Figure 10-8: Settings impact on restraint characteristic
10.3 Fault locator

10.3.1 Description

Fault type determination is required for calculation of fault location. The algorithm uses the angle between the negative
and positive sequence components of the relay currents. To improve accuracy and speed of operation, the fault
components of the currents are used; that is, the pre-fault phasors are subtracted from the measured current phasors. In
addition to the angle relationships, certain extra checks are performed on magnitudes of the negative and zero-sequence
currents.
The single-ended fault location method assumes that the fault components of the currents supplied from the local (A) and
remote (B) systems are in phase. The figure shows an equivalent system for fault location.
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10-20 L30 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL