CPC H02H 11/00 (2013.01) [G01R 19/2513 (2013.01); H02H 3/027 (2013.01); H02H 3/16 (2013.01); H02H 3/26 (2013.01); H02J 3/001 (2020.01); H02J 13/00002 (2020.01)] | 20 Claims |
1. A method for engaging a trip signal at an interrupting device of a set of three phase electric distribution lines, the method comprising:
measuring, via one or more sensors, a potential from a three phase transformer at one end of the set of three phase distribution lines; detecting an abnormal condition with respect to the set of distribution lines based on the measured potential, wherein the abnormal condition is selected from the group consisting of: (a) a voltage unbalance; (b) a negative sequence voltage unbalance; or (c) both a voltage unbalance and a negative sequence unbalance; responsive to detecting an abnormal condition, transmitting the trip signal from another device to the interrupting device without use of a positive sequence power source, thereby blocking the interrupting device at least temporarily from closing;
wherein the detection is performed via a tripping apparatus that includes four conductors, three of the four conductors tapping the three phase transformer, and one of the four conductors being a ground or neutral.
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