Cable Fault Locator
TDR-109 “SWIFT+” for Power Lines applications


TDR-109 is a high-precision 3-channel digital reflectometer designed to determine the distances to all types of faults in the power cable lines: open, short, sleeve, cable splice, parallel branches, wet cable, high-resistance faults, intermittent breakdown and etc.


TDR-109 provides the following measurement methods:

  • Time Domain Reflectometry (TDR);
  • Arc-Reflection Method(ARM);
  • Oscillatory Discharge Methods (ICM, Decay);

Sphere of application:

The implementation of additional high-voltage methods makes it possible to locate high-resistance faults on power cables.

Pulse TDR TDR-109 is used for control when installing or operating the following types of cable lines:

  • power cables;
  • aerial cable lines;
  • system cables communications;
  • signal and control cables;
  • computer networks;
  • television and radio cable lines;
  • to determine the length of the cable during its manufacture, storage and trade;
Implemented methods

Implemented measurement methods overview

TDR-109 implements the following measurement methods:

  • Time Domain Reflectometry (TDR)
  • Arc Reflection Method(ARM or SIM )*
  • Impulse Current Method (ICM)*
  • DECAY  travelling wave method*

* when used in complex with high-voltage pulse generators (HVPG), for example: ADG-200-2 “STINGRAY-M”

Time Domain Reflectometry (TDR)

the most accurate and safe mode – effective for diagnosing low-resistance faults (less than 1 kOhm) and short circuits, searching for cable line breaks, joints/splices, parallel branches, etc.

More about this method:

Time Domain Reflectometry (TDR). Theoretical basis.

Time Domain Reflectometry (TDR). Practical techniques.

The method allows you to perform the following works:
• cable length measurement;
• measurement of distances to impedance inhomogeneities or faults;
• measurement VoP (v/2) of the line at its known length;
• determination of the nature of cable fault.

The TDR method is based on the phenomenon of partial reflection of electromagnetic waves in places where the impedance of a line changes. When measuring by the TDR method, a short voltage probe pulse is sent to the line, which, partially reflected from the impedance inhomogeneities, returns back. The reflected pulses return to the TDR-device some time after the sending of the probe pulse. Knowing the signal velocity of propagation in the line and the delay time of the reflected signal, it is possible to calculate the distance to the impedance inhomogeneity (fault). Reflections from the probe pulse are observed on a range-scaled screen, and by their form can be determined the nature of inhomogeneity.
Inhomogeneities of the impedance are the result of a violation of the cable production technology, as well as a consequence of mechanical and electrical damage during the construction and operation of the cable. Inhomogeneity also occurs in the points where any devices are connected to the cable line (coupling, branch, cable splice/joint, Pupin coil, etc.), or in points of faults (open circuit, short circuit, wetting of the cable core, leakage to earth, leakage to an adjacent wire, broken pairs, etc.). The TDR method makes it possible to see multiple inhomogeneities, both discrete and distributed, depending on the ratio of their length and the minimum wavelength of the probe pulse spectrum.

TDR-109 reflectogram examples:

TDR-109 measurement example: direct connection to the cable, open far-end

Arc Reflection Method (ARM)

in combination with a High-Voltage Pulse Generator (HVPG), for example ADG-200-2 “STINGRAY-M”, allows to detect High-Resistance faults (> 1 kOhm) with the accuracy of the TDR method.

You can read more about this method at the link:

Arc Reflection Method (ARM) for high-resistance faults prelocation

Localization of high-resistance faults at the site of a defect is usually difficult when using a low-voltage pulse measurement method. One of the ways to localize such defects on power cables is the Arc Reflection Method (ARM).

The essence of the ARM method is that a short-term electric arc is created (with the help of High-Voltage Pulse Generator ) at the place of cable damage. A burning electric arc has a low resistance, so it is well detected by an TDR.

The method does not require preliminary burning of the insulation and is especially effective when working on cables with a polyethylene sheath.

An example of reflectogram of a cable line obtained by a ARM method:

Localization of high-resistance faults by the ARM method of the TDR-109. The reflectogram of the cable obtained by the TDR method is displayed in green color. We see the whole cable to the end, the high-resistance fault is not determined. The reflectogram recorded by the reflectometer during a short-term breakdown in the point of the fault is displayed in blue color. Signal is reflected with negative polarity from low arc-resistance.

Impulse Current Method (ICM), DECAY  travelling wave method

in combination with a High-Voltage Pulse Generator (HVPG), for example ADG-200-2 “STINGRAY-M”, it allows to determine the location of high-resistance defects in cases where the fault is distributed in nature and electrical breakdown occurs without ARC ignition (respectively, ARM is not applicable)

You can read more about this method at the link:

Impulse Current Method (ICM), DECAY  travelling wave method for determining high resistance faults

Locating faults caused by a floating breakdown of insulation is usually difficult when using a low-voltage TDR measurement method. One of the ways to localize such defects on power cables is the oscillatory discharge method (ICM / Decay).

The method of oscillatory discharge (wave) is based on measuring the duration of the period of the oscillatory process that occurs during the breakdown of a charged cable.

To create an oscillatory process in the cable, with the help of HVPG, the voltage in the cable is smoothly raised to breakdown, but not higher than the value determined by the norms of preventive tests, or with the help of HVPG, the built-in high-voltage capacitor is charged and then discharged into the cable.

The reflectometer in this case acts as an oscilloscope that records the oscillatory process in the cable (using a current sensor – ICM method or voltage sensor – Decay method).

An insulation defect causes a breakdown at the place of damage, a and an oscillatory discharge occurs in the cable. Knowing the speed of propagation of the electromagnetic wave along the line and the period of the oscillatory process, it is possible to calculate the distance to the breakdown:

X is the distance to the floating breakdown, m
v – velocity of electromagnetic wave propagation in the cable , m / µs
tpp – time of the period of the oscillatory process, µs
s – speed of light equal to 299.8 m / µs
KU – the value of the shortening factor
Localization of high-resistance faults by the TDR-109 by the Impulse Current Method (ICM). The distance to the high-resistance defect is defined as the period of the oscillatory process arising during the breakdown in the cable.


  • the possibility of applying the most modern methods of diagnosis and cable fault prelocation: TDR method, Arc-Reflection Method (ARM), the voltage wave(Decay), the method of the current wave(ICM);
  • 3 line inputs to connect to the three phase cables;
  • display waveforms on a color 5.7 ” TFT-LCD with a resolution of 640×480 pixels;
  • the ability to display all measurement channels in all combinations (6 waveforms);
  • non-volatile memory – at least 1000 waveforms, up to six of them for comparison;
  • subtraction mode to show only waveform differences;
  • maximum range – 128 km;
  • the possibility of sensing with an increased pulse amplitude (U2 = 86 V on open circuit ) to work on cables with high attenuation;
  • real time measuring;
  • two cursors measuring system;
  • possibility of a detailed review of any portion of the reflectogram – the function of multiple zoom;
  • asynchronous noise suppression;
  • intermittent fault mode detection  – the function “Capture”;
  • built-in velocity factor table up to 300 values;
  • External USB Flash drive to archive waveforms library and VOP library, as well as restore libraries to the device memory from USB flash;
  • splash proof and hermetically closing body with high mechanical strength (protection class IP67);


Measurement Modes
  • Time Domain Reflectometry (TDR);
  • Arc-Reflection Method (ARM) ;
  • Current method (ICM);
  • Decay;
DisplayColor TFT 5.7″ (640×480 pixels)
Range measuring distance (delay time)from 0 to 128000 m (0 to 1280 μs)
Sub-bands of distance (time delay)0 – 62.5 m (0 – 0,625 μs), 0 – 125 m (0 – 1.25 μs), 0 – 250 m (0 – 2.5 μs), 0 – 500 m (0 -5 μs); 0 – 1000 m (0 – 10 μs), 0 – 2000 m (0 – 20 μs), 0 – 4000 m (0 – 40 μs), 0 – 8000 m (0 – 80 μs) 0 – 16000 m (0 – 160 μs), 0 – 32000 m (0 – 320 μs) 0 – 64000 m (0 – 640 μs) 0 – 128,000 m (0 – 1280 μs)
Distance instrumental errorfrom 0.01% to 0.2% of subband (from 12.5 cm to 8 m at VOP = 60%)
The effective sampling rate800 MHz
Range concerted resistancefrom 20 Ω to 600 Ω
Probe pulse durationfrom 10 ns to 100 μs
The amplitude of the probe pulse (at open circuit)
  • U1 – not less than 18 V;
  • U2 – not less than 86 V;
The sensitivity of the receiving pathbetter than 1 mV
The dynamic rangenot less 80 dB
The setting range of the velocity factorfrom 1.000 to 3.000 (step 0.001)
Time delay adjustment range (Arc-Reflection method)from 0 to 50 ms (step 0.2 ms)
Synchronization (Arc-Reflection method)
  • measuring input
  • TRIG input
Amplitude synchronization (wave method)-60 to +60 V, step 2V
Continuous battery operating timeat least 6 hours
Time of continuous operating time through the chargerunlimited
Dimensions70x246x124 mm
Operating temperature rangefrom -20 °C to +40 °C
Weight with a batterynot more than 2.5 kg
Delivery Contents

Delivery Contents

Cable Fault Locator TDR-1091 item
AC Adapter 12 V1 item
Connecting cable 75 Ohm, BNC.M – «Alligator clip»1 item
Connecting cable 75 Ohm, 1 m, BNC.M-BNC.M 5 items
User Manual1 item
CD-ROM with software1 item
Accessories bag1 item

Additional equipment

Arc Discharge Generator ADG-200-2 (10 kV, 200 J, 17kg)
Voltage protection unit UP-1 for operation on cables under voltage up to 380 V;
Extension cable   5 m, 75 Ohm, BNC.M-BNC.F
Connecting cable 1.5 m, 75 Ohm, BNC.M-crocodiles 25.4   mm
Connecting cable     0.1 m, 75 Ohm, & nbsp; BNC.M-crocodiles
Adapter BNC.M – terminals
USB-Flash drive
Рефлектометр для силовых линий TDR-109


The device is certified by the State Standard of Russia and entered in the State Register under No. 49090-12. Certificate of type approval of measuring instruments RU.C.27.004.A No. 45536


We invite regional dealers to cooperate

Detailed information - by e-mail or by phone +7 (812) 334-37-36

Contacts and company details

Legal adress:

Russian Federation, 196244, St.Petersburg, Vitebsky pr. 23/1 

Postal address:

Russia, 196244, St.Petersburg, Post Box 28



+7 (812) 334-37-37,
+7 (812) 334-37-36,
+7 (812) 334-37-38
+7 (911) 729-81-06
Bank details:

Noth-West Bank PAO «Sberbank»
P/a 40702810455220115490
C/a 30101810500000000653
BIK 044030653
INN 7810609756
KPP 781001001
Code OKONH 95300
Code OKPO 23133821
OGRN 1027804871544
OKVED 33.20.6