Patent ID: 11942776
Assignee: VIKING PROTECTION SYSTEMS LLC
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A system for preventing ground fault or other short circuit in a three-phase electric transmission line system having at least three lines, caused by a break in a line, which utilizes at least dual high sensitivity monitoring, which comprises:
A. a three-phase electric transmission system having at least three lines and a plurality of circuit breakers;
B. a plurality of first relay devices connected to said transmission system, said plurality of first relay devices having a best sensitivity for measuring line differential overcurrent of above 0.1 amps, and thereby being low sensitivity relay devices;
C. a plurality of second relay devices connected to said transmission system, said plurality of second relay devices having a best sensitivity for measuring line differential overcurrent of at least 0.01 amps or lower amps, and thereby being high sensitivity relay devices, wherein said plurality of second relay devices are positioned in parallel to said first set of rely devices on said transmission system;
D. a programmable relay protection system functionally connected to said three-phase electric transmission system, including functionally connected to said plurality of second relay devices on each line of said electric transmission line system, said relay protection system being programmed to include:
a) preset parameter ranges of at least two high sensitivity electric operating conditions, said preset ranges being acceptable operating parameter ranges, one of said operating conditions being instantaneous undercurrent, and one other of said operating conditions being selected from the group consisting of a) line differential overcurrent; b) negative sequence overcurrent and c) combinations thereof, wherein said plurality of second relay devices are programmed to be highly sensitive so as to monitor and measure instantaneous undercurrent in the range of 0.01 to 1 amps, and wherein said plurality of second relay devices are programmed to be highly sensitive so as to monitor and measure one other of said operating conditions selected from the group consisting of a) line differential overcurrent; b) negative sequence overcurrent and c) combinations thereof, in the range of 0.01 to 0.1 amps, and;
b) monitoring means to monitor each line at each of said plurality of second relay devices for said at least two operating conditions;
c) permitting closed circuit operation when all of said lines show said at least two operating conditions are within said preset acceptable operating parameter ranges;
d) sensing open conductor broken line changes and tripping a circuit breaker on a broken line when that line shows said at least two operating conditions are outside said preset parameter ranges;
e) and completing the sensing and tripping within 1.0 second;

E. a communications system for communications between said second relay devices and said circuit breakers such that when said relay protection system senses an open conductor broken line when said at least two operating conditions fall outside of said preset parameter ranges, communicating to open the circuit breaker on said broken line, thereby shutting down power to said broken line before it otherwise causes a ground fault or other short circuit, within 1.0 second of sensing said open conductor broken line.