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L60 LINE PHASE COMPARISON SYSTEM – INSTRUCTION MANUAL
OVERVIEW
CHAPTER 9: THEORY OF OPERATION
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detectors are provided. They initiate phase comparison only when a fault occurs on, or in the general vicinity of, the
protected line. A simplified sketch of the logic of a phase comparison blocking scheme including fault detectors is
illustrated in the Single-Phase Comparison Blocking Scheme Principle figure that follows. This is a somewhat more fully
developed version of 2D, and the same logic is present at both ends of a two-terminal line.
Figure 9-4: Three-terminal line phase comparison