METHOD FOR SELECTIVE ZERO-SEQUENCE CURRENT PROTECTION

摘要

FIELD: power engineering; relay protective gear for substations. SUBSTANCE: method involves comparison of absolute values of currents through connections and their comparison with total currents through connections by their conversion into voltage and rectification, detection of open circuit in connection carrying highest current, turning-on of protective gear in faulty connection, and interlocking of protective gear in good connection or interlocking of protective gears of connections in case of external fault by means of selective element. EFFECT: provision for dispensing with potential transformers, their secondary circuits, and voltage windings.