Effectiveness of Distribution Protection
Each time a distribution substation is momentarily de-energized and re-energized, inrush current in the transformer neutral can cause the station backup ground relay to trip unexpectedly. It's difficult to understand these transients, and what action to take. To analyze the interaction between line disturbances and substation protective devices, the author (John Boyle) used digital recorders to simultaneously collect data at critical field locations.
Effectiveness of Distribution Protection explains the actual oscillographic data, but you can also analyze it yourself. You'll see how current and voltage surges in subtransmission phase lines affect neutrals. And you'll learn the solutions: install low-loss transformers, reduce the R+jX compensation, and choose relays that aren't sensitive to third-order harmonics.
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