Resistive fault sectionalization

A method for testing a cable pair (TIP,RING) to locate a shunt resistance fault (R.sub.F) between first (A) and second (B) test positions by determining the conductor (TIP or RING) resistance (R.sub.X) between said fault and said second test position, said method

• CHARACTERIZED BY THE STEPS OF
• measuring the DC resistance (A.sub.1) of said pair at said first test position with said pair open-circuited at said second test position,
• adding a preselected resistance (.+-.R) in series with one conductor (TIP or RING) of said pair to form a series combination,
• measuring the DC resistance (A.sub.2) of said series combination at said second test position with said pair open-circuited at said first test position,
• measuring the DC resistance (A.sub.3) of said series combination at said second test position with said pair short-circuited at said first test position, and
• determining the value of said resistance (R.sub.X) from the expression
• (R.sub.X .+-.R).sup.2 -A.sub.2 (R.sub.X .+-.R)+(A.sub.1 /4) (A.sub.3 -A.sub.2)+(A.sub.2 /2).sup.2 =0.

Testing apparatus for locating a pair fault (R.sub.F) between first (A) and second (B) test positions by determining the conductor (TIP or RING) resistance (R.sub.X) between said fault and said second test location, said apparatus

• CHARACTERIZED BY
• first means at said first location to sequentially configure said pair (i) for measuring the DC resistance (A.sub.1), (ii) by open-circuiting and (iii) by short-circuiting said pair, respectively, and
• second means at said second location, operating simultaneously with said first means, to configure said pair (i) by open-circuiting said pair, (ii) for measuring the DC resistance (A.sub.2), and (iii) for measuring the DC resistance (A.sub.3), respectively, of said pair,
• wherein said resistance (R.sub.X) is a solution to the quadratic expression
• R.sub.X.sup.2 -A.sub.2 R.sub.X +(A.sub.1 /4) (A.sub.3 -A.sub.2)+(A.sub.2 /2).sup.2 =0.

Testing apparatus for locating a pair fault (R.sub.F) between first (A) and second (B) test locations by determining the conductor (TIP or RING) resistance (R.sub.X) between said fault and said second test location, said apparatus

• CHARACTERIZED BY
• first means at said first location to sequentially configure said pair (i) for measuring the DC resistance (A.sub.1), by (ii) open-circuiting and (iii) by short-circuiting said pair, respectively, and
• second means at said second location, operating simultaneously with said first means, to configure said pair (i) by open-circuiting said pair, (ii) by adding a preselected resistor (.+-.R) in series with one conductor of said pair and measuring the DC resistance (A.sub.2) of the series combination, and (iii) by measuring the DC resistance (A.sub.3) of said combination,
• wherein said resistance (R.sub.X) is a solution to the quadratic expression
• (R.sub.X .+-.R).sup.2 -A.sub.2 (R.sub.X .+-.R)+(A.sub.1 /4) (A.sub.3 -A.sub.2)+(A.sub.2 /2).sup.2 -0.

Wire-pair apparatus for testing a resistive fault (R.sub.F) located between first (A) and second (B) test locations and for determining the resistance (R.sub.X) of one wire (TIP or RING) between said fault and said second test location, said apparatus

• CHARACTERIZED BY
• first means at said first location having three sequential modes of operation including:
• a first mode for measuring the DC resistance (A.sub.1) of said pair;
• a second mode for disconnecting said first means from said pair;
• and a third mode for shorting said pair, and
• second means at said second location operating in one-to-one correspondence to said modes for:
• disconnecting said second means from said pair during said first mode;
• measuring the DC resistance (A.sub.2) of said pair during said second mode;
• and measuring the DC resistance (A.sub.3) of said pair during said third mode,
• wherein said resistance (R.sub.X) is a solution to the quadratic expression
• R.sub.X.sup.2 -A.sub.2 R.sub.X +(A.sub.1 /4) (A.sub.3 -A.sub.2)+(A.sub.2 /2).sup.2 =0.