Sequence current variable quantity differential protection method and system for multi-terminal line

• Main Authors: YAN ZHIHUA, LI XINYAN, YANG FAN, XIE YASONG, HUANG JIWEI, NIE JUANHONG, WU YEKAI, BI JINYANG, XIE JIE, ZHAO ZHIHONG, XU GANG, TIAN ZHENHUA, ZHANG YUEPIN
• Format: Patent
• Language: Chinese; English
• Published: 16.07.2024
• Subjects: CONVERSION OR DISTRIBUTION OF ELECTRIC POWER; ELECTRICITY; EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS; GENERATION

The invention discloses a sequence current variable quantity differential protection method and system for a multi-terminal line, and the method comprises the steps: respectively forming the differential protection discrimination logic of each sequence current variable quantity through the positive sequence, negative sequence and zero sequence current variable quantity of each terminal, and if the differential current of each sequence current variable quantity is greater than a corresponding motion threshold, determining that the sequence current variable quantity differential current is greater than a corresponding motion threshold; meanwhile, the braking current is larger than the braking coefficient and multiplied by the corresponding sequence current variable quantity, action is conducted after time delay confirmation, and tripping is conducted according to the reclosing condition and the phase selection logic of the phase differential current. According to the invention, an auxiliary discrimination mode