Appeal No. 2002-0496 Page 3
Application No. 09/182,542
FDI provide a direction and a distance thereto. A repair crew uses these data to
determine where to dig to find the faulty portion of the failed cable section.
The appellants invention comprises two embodiments. (Wharton Decl. at 4.)
The first embodiment of the FDI includes a microprocessor, a delay element, a digital
memory, and a phase monitor. When a section of cable breaks down, the
microprocessor detects radio frequency ("RF") signals generated by resultant electrical
arcing. Upon breakdown, the data stored in the delay element represent the RF signals
on the cable immediately before, during, and immediately after the occurrence of fault.
The microprocessor loads these data into the digital memory. The microprocessor or
an external fault analyzer then generates a function that approximates the response of
the cable to a short circuit. The function is defined by an equation having parameters
that may be adjusted to simulate the position of the fault on the cable system. The
parameters are adjusted until the values produced by the equation most closely match
the stored values. The parameters of the equation are then used to specify the
distance from the FDI to the fault. (Id.)
The phase monitor monitors the instantaneous phase of the alternating current
("AC") power signal in the loop. The phase of the AC power signal and the relative
polarization of the particular sequence of pulses resulting from the fault determine the
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