Which one is the Proper Fault Location Method ? Typical Cable Faults Insulation Faults Partly flooded cable Totally flooded C b ≠ C a R b ≠ R a Recommended Fault Location Method Disturbing Voltage ▼ Murray Küpfmüller 3-Point (a-b) 3-Point Graaf C unbalance R difference Low level Medium level DC Medium level AC High level AC Intermittent Active Sensitive Active Sensitive Active Sensitive Active Sensitive Active Sensitive Active Sensitive Active Protected Active Protected Active Protected Active Protected Active Protected Active Protected Active Protected Active Protected Active Protected Active Protected Active Protected Active Protected Passive Passive Passive Passive Passive Passive Repeated Küpfmüller Graaf Passive Passive To learn more click on the selected method! ELEKTR NIKA

Disturbers ELEKTR NIKA The expected disturbing voltage depends on: A.) The function of neighboring pairs in the cable  Intermittent disturbing voltages are expected if the neighboring pairs are used for POTS  DC disturbing voltage is expected if the neighboring pairs are used only for ISDN    No disturbing voltage is expected if the neighboring pairs are used only for data transfer B.) The distance to electrical railway    High disturbing AC voltage is expected if the  cable is very close to the track  Low disturbing AC voltage is expected if the  cable is fare enough from the track ELEKTR NIKA

Active Bridge Murray Method in Sensitive mode Recommended when: ■ only one wire of a pair is faulty ■ the level of disturbing voltages are low The Murray method consists of 2 measurements:   ■ Measurement of disturbing voltages   ■ Bridge measurement with strap on the far end  ECFL 30 automatically performs the 2 measurements with the help of the remote controlled switch ELC 30 The result of Murray measurement is: Lx/L In addition ECFL 30 provides:   ■ RL loop resistance   ■ FaE insulation resistance   ■ Rx resistance to fault ■ Lx distance to fault The conditions of accurate results:  ■ Ia and Ib < 450 uA  ■ Ф wire a=Ф wire b  ■ FbE>1000 x FaE  ■ FbE>10 MOhm If the disturbing voltages overload the input repeat the measurement in Protected mode ELEKTR NIKA

Active Bridge Murray Method in Protected mode Recommended when: ■ only one wire of a pair is faulty ■ the level of disturbing voltages are medium The Murray method consists of 2 measurements:   ■ Measurement of disturbing voltages   ■ Bridge measurement with strap on the far end  ECFL 30 automatically performs the 2 measurements with the help of the remote controlled switch ELC 30 The result of Murray measurement is: Lx/L In addition ECFL 30 provides:   ■ RL loop resistance   ■ FaE insulation resistance   ■ Rx resistance to fault ■ Lx distance to fault The conditions of accurate results:  ■ Ia and Ib < 7 mA  ■ Ф wire a=Ф wire b  ■ FbE>1000 x FaE  ■ FbE>10 MOhm If the disturbing voltages overload the input repeat the measurement with the passive bridge of ECFL 30 ELEKTR NIKA

Passive Bridge Murray Method Recommended when: ■ only one wire of a pair is faulty ■ the level of disturbing voltages are high The Murray method requires manual bridge balancing with helipot M.    ■ the measuring voltage is connected to the ground ■ wire a and wire b should be interconnected at the far end The far end can be automatically closed/open with the help of the remote controlled switch ELC 30 The result of Murray measurement is: Lx/L In addition ECFL 30 provides:   ■ RL loop resistance   ■ FaE insulation resistance   ■ Rx resistance to fault ■ Lx distance to fault The conditions of accurate results:  ■ Ф wire a=Ф wire b  ■ FbE>1000 x FaE  ■ FbE>10 MOhm If the disturbing voltages overload the input repeat the measurement with the passive bridge of ECFL 30 ELEKTR NIKA

Active Bridge Küpfmüller Method in Sensitive mode Recommended when: ■ booth wires of a pair are faulty ■ the level of disturbing voltages are low The Küpfmüller method consists of 2 measurements:   ■ First measurement with open far end   ■ Second measurement with strap on the far end  ECFL 30 automatically performs the 2 measurements with the help of the remote controlled switch ELC 30 The result of Küpfmüller measurement is: Lx/L In addition ECFL 30 provides:   ■ RL loop resistance   ■ FaE and FbE insulation resistances   ■ Rx resistance to fault ■ Lx distance to fault The conditions of accurate results:  ■ Ia and Ib < 450 uA  ■ Ф wire a=Ф wire b  ■ 0,5>FaE / FbE>2  ■ FaE + FbE>100 x R loop If the disturbing voltages overload the input repeat the measurement in Protected mode ELEKTR NIKA

Active Bridge Küpfmüller Method in Protected mode Recommended when: ■ booth wires of a pair are faulty ■ the level of disturbing voltages are medium The Küpfmüller method consists of 2 measurements:   ■ First measurement with open far end   ■ Second measurement with strap on the far end  ECFL 30 automatically performs the 2 measurements with the help of the remote controlled switch ELC 30 The result of Küpfmüller measurement is: Lx/L In addition ECFL 30 provides:   ■ RL loop resistance   ■ FaE and FbE insulation resistances   ■ Rx resistance to fault ■ Lx distance to fault The conditions of accurate results:  ■ Ia and Ib < 7 mA  ■ Ф wire a=Ф wire b  ■ 0,5>FaE / FbE>2  ■ FaE + FbE>100 x R loop If the disturbing voltages overload the input repeat the measurement with the passive bridge of ECFL 30 ELEKTR NIKA

Passive Bridge Küpfmüller Method Recommended when: ■ booth wires of a pair are faulty ■ the level of disturbing voltages are high The Küpfmüller method requires 2 manual bridge balancings with helipot M.    ■ First balancing with open far end   ■ Second balancing with strap on the far end  The far end can be automatically closed/open with the help of the remote controlled switch ELC 30 The result of Küpfmüller measurement is: Lx/L In addition ECFL 30 provides:   ■ RL loop resistance   ■ FaE and FbE insulation resistances   ■ Rx resistance to fault ■ Lx distance to fault The conditions of accurate results:  ■ Ф wire a=Ф wire b  ■ 0,5>FaE / FbE>2  ■ FaE + FbE>100 x R loop In case of strongly intermittent disturbing voltages repeat the measurement with the Graaf method ELEKTR NIKA

Active Bridge Repeated Küpfmüller Method Recommended when: ■ booth wires of a pair are faulty ■ the level of disturbing voltages are intermittent That method is a sequence of repeated Küpfmüller measurements consisting of 15 part measurements alternating : ■ 8 measurements with open loop (L) ■ 7 measurements with closed loop (K) The far end is automatically closed/open with the help of the remote controlled switch ELC 30 The Lx/L results are displayed in two columns and a histogram When the sequence is completed ECFL 30 selects the acceptable Lx/L results and calculates the average of the accepted results. The unacceptable results are omitted and marked with asterisks. ELEKTR NIKA

Active Bridge 3-Point (a-b) Method in Sensitive mode Recommended when: ■ the insulation between wires and ground is good ■ the insulation resistance between wires a and b is low ■ some healthy pairs are available ■ the level of disturbing voltages are low Faulty pair FaE Healthy auxiliary wires The 3-Point method consists of 3 measurements:   ■ First measurement when the measuring voltage is connected to wire a   ■ Second measurement when the measuring voltage is connected to the ground   ■ Third measurement when the measuring voltage is connected to wire c ECFL 30 automatically performs the 3 measurements with the help of the remote controlled switch ELC 30 The result of 3 Point measurement is: Lx/L In addition ECFL 30 provides:   ■ RL loop resistance   ■ FaE insulation resistance   ■ Rx resistance to fault ■ Lx distance to fault The conditions of accurate results:  ■ Ia and Ib < 450 uA ■ The insulation resistance of auxiliary wires must be thousand time as high than that of the faulty one.   If the disturbing voltages overload the input repeat the measurement in Protected mode ELEKTR NIKA

Active Bridge 3-Point (a-b) Method in Protected mode Recommended when: ■ the insulation between wires and ground is good ■ the insulation resistance between wires a and b is low ■ some healthy pairs are available ■ the level of disturbing voltages are medium Faulty pair FaE Healthy auxiliary wires The 3-Point method consists of 3 measurements:   ■ First measurement when the measuring voltage is connected to wire a   ■ Second measurement when the measuring voltage is connected to the ground   ■ Third measurement when the measuring voltage is connected to wire c ECFL 30 automatically performs the 3 measurements with the help of the remote controlled switch ELC 30 The result of 3 Point measurement is: Lx/L In addition ECFL 30 provides:   ■ RL loop resistance   ■ FaE insulation resistance   ■ Rx resistance to fault ■ Lx distance to fault The conditions of accurate results:  ■ Ia and Ib < 7mA ■ The insulation resistance of auxiliary wires must be thousand time as high than that of the faulty one.   If the disturbing voltage overload the input repeat the measurement with the passive bridge of ECFL 30 ELEKTR NIKA

Passive Bridge 3-Point (a-b) Method Recommended when: ■ the insulation between wires and ground is good ■ the insulation resistance between wires a and b is low ■ some healthy pairs are available ■ the level of disturbing voltages are high Faulty pair FaE Healthy auxiliary wires The 3-Point method requires 3 manual bridge balancing with helipot M.   ■ First balancing when the measuring voltage is connected to wire a   ■ Second balancing when the measuring voltage is connected to the ground   ■ Third balancing when the measuring voltage is connected to wire c The far end can be automatically closed with the help of the remote controlled switch ELC 30 The result of 3 Point measurement is: Lx/L In addition ECFL 30 provides:   ■ RL loop resistance   ■ FaE insulation resistance   ■ Rx resistance to fault ■ Lx distance to fault The condition of accurate results:  ■ The insulation resistance of auxiliary wires must be thousand time as high than that of the faulty one.   In case of strongly intermittent disturbing voltages repeat the measurement with the Graaf method ELEKTR NIKA

Active Bridge 3-Point Method in Sensitive mode Recommended when: ■ the gauge of wires in a pair are different ■ some healthy pairs are available ■ the level of disturbing voltages are low The 3-Point method consists of 3 measurements:   ■ First measurement when the measuring voltage is connected to wire a   ■ Second measurement when the measuring voltage is connected to the ground   ■ Third measurement when the measuring voltage is connected to wire c ECFL 30 automatically performs the 3 measurements with the help of the remote controlled switch ELC 30 The result of 3 Point measurement is: Lx/L In addition ECFL 30 provides:   ■ RL loop resistance   ■ FaE insulation resistance   ■ Rx resistance to fault ■ Lx distance to fault The conditions of accurate results:  ■ Ia and Ib < 450 uA ■ The insulation resistance of auxiliary wires must be thousand time as high than that of the faulty one.   If the disturbing voltages overload the input repeat the measurement in Protected mode ELEKTR NIKA

Active Bridge 3-Point Method in Protected mode Recommended when: ■ the gauge of wires in a pair are different ■ some healthy pairs are available ■ the level of disturbing voltages are medium The 3-Point method consists of 3 measurements:   ■ First measurement when the measuring voltage is connected to wire a   ■ Second measurement when the measuring voltage is connected to the ground   ■ Third measurement when the measuring voltage is connected to wire c ECFL 30 automatically performs the 3 measurements with the help of the remote controlled switch ELC 30 The result of 3 Point measurement is: Lx/L In addition ECFL 30 provides:   ■ RL loop resistance   ■ FaE insulation resistance   ■ Rx resistance to fault ■ Lx distance to fault The conditions of accurate results:  ■ Ia and Ib < 7mA ■ The insulation resistance of auxiliary wires must be thousand time as high than that of the faulty one.   If the disturbing voltage overload the input repeat the measurement with the passive bridge of ECFL 30 ELEKTR NIKA

Passive Bridge 3-Point Method Recommended when: ■ the gauge of wires in a pair are different ■ some healthy pairs are available ■ the level of disturbing voltages are high The 3-Point method requires 3 manual bridge balancings with helipot M.   ■ First balancing when the measuring voltage is connected to wire a   ■ Second balancing when the measuring voltage is connected to the ground   ■ Third balancing when the measuring voltage is connected to wire c The far end can be automatically closed with the help of the remote controlled switch ELC 30 The result of 3 Point measurement is: Lx/L In addition ECFL 30 provides:   ■ RL loop resistance   ■ FaE insulation resistance   ■ Rx resistance to fault ■ Lx distance to fault The condition of accurate results:  ■ The insulation resistance of auxiliary wires must be thousand time as high than that of the faulty one.   In case of strongly intermittent disturbing voltages repeat the measurement with the Graaf method ELEKTR NIKA

Synchronous Graaf Method Recommended: for Fault Location of Totally Flooded Cables Graaf method can be used when no other method is applicable due to disturbing DC currents. That method is based on disturbing DC current measurement at the ends of the tested pair. The location of fault is calculated from the rate of the measured DC currents (I1 / I2 ) The level of disturbing DC currents is usually intermittent. For the sake of proper test result the master and slave instruments perform synchronous current measurements at the cable ends. In this case the current rate ( I1 / I2 ) does not depend on the actual value of disturbing currents. Notice: The current measuring method was invented by Dr Robert Van de Graaf in 1931 ELEKTR NIKA

The Original Graaf Method and its Problems The Theory was perfect: The result doesn't depend on the actual value of currents But in the practice it was not satisfactory due to the following problems: 1.) The sensitivity and accuracy of available current meters were not enough at that time 2.) The reading of meters was strongly subjective in case of intermitting currents ECFL 30 eliminates all the problems of the original Graaf method: 1.) The features of current meters are much better (Sensitivity:3 uA, Ri:1 Ohm, Accuracy: 0,3%) 2.) The master and slave instruments perform synchronous current measurements at the cable ends. ELEKTR NIKA

Resistance Difference Measurement The active bridge of ECFL 30 is accurate and comfortable The passive bridge of ECFL 30 is disturbing voltage tolerant ECFL 30 provides the following results: Ra, Rb, Rloop, Δ R, % ELEKTR NIKA

Capacitance Unbalance Measurement The active bridge of ECFL 30 is accurate and comfortable The passive bridge of ECFL 30 is disturbing voltage tolerant ELEKTR NIKA

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