Walsh Functions for Digital Impedance Relaying of Power Lines
by J. W. Horton
Impedance distance relaying for fault-protection of a plurality of high-voltage lines has not been accomplished with a minicomputer because of the burden of time placed upon these computers. A new method for computing impedance from data samples is proposed, which would employ only the computer operations of Add, Subtract, and Shift. This is valuable because these operations are one to two orders of magnitude faster on present day minicomputers than the operations of Multiply, Divide, Square, and Square Root. The new method is based upon the use of Walsh functions. When compared with the best competitive method, this new method shows superiority in speed and an accuracy that meets proposed objectives.